Patent Publication Number: US-6993710-B1

Title: Method and system for displaying changes of source code

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The following identified U.S. patent applications are relied upon and are incorporated by reference in this application:
         U.S. Provisional Application No. 60/157,826, entitled “Visual Unified Modeling Language Development Tool,” filed on Oct. 5, 1999;   U.S. Provisional Application No. 60/199,046, entitled “Software Development Tool,” filed on Apr. 21, 2000;   U.S. patent application Ser. No. 09/680,063 entitled “Method And System For Developing Software,” and filed on the same date herewith;   U.S. patent application Ser. No. 09/680,030 entitled “Method And System For Generating, Applying, And Defining A Pattern,” and filed on the same date herewith; and   U.S. patent application Ser. No. 09/680,064 entitled “Method And System For Collapsing A Graphical Representation Of Related Elements,” and filed on the same date herewith.       

   FIELD OF THE INVENTION 
   The present invention relates to a method and system for developing software. More particularly, the invention relates to a method and system for tracking changes made to source code, and displaying the source code with these changes. 
   BACKGROUND OF THE INVENTION 
   Computer instructions are written in source code. Although a skilled programmer can understand source code to determine what the code is designed to accomplish, with highly complex software systems, a graphical representation or model of the source code is helpful to organize and visualize the structure and components of the system. Using models, the complex systems are easily identified, and the structural and behavioral patterns can be visualized and documented. 
   The well-known Unified Modeling Language (UML) is a general-purpose notational language for visualizing, specifying, constructing, and documenting complex software systems. UML is used to model systems ranging from business information systems to Web-based distributed systems, to real-time embedded systems. UML formalizes the notion that real-world objects are best modeled as self-contained entities that contain both data and functionality. UML is more clearly described in the following references, which are incorporated herein by reference: (1) Martin Fowler,  UML Distilled Second Edition: Applying the Standard Object Modeling Language , Addison-Wesley (1999); (2) Booch, Rumbaugh, and Jacobson,  The Unified Modeling Language User Guide , Addison-Wesley (1998); (3) Peter Coad, Jeff DeLuca, and Eric Lefebvre,  Java Modeling in Color with UML: Enterprise Components and Process , Prentice Hall (1999); and (4) Peter Coad, Mark Mayfield, and Jonathan Kern,  Java Design: Building Better Apps  &amp;  Applets  (2nd Ed.), Prentice Hall (1998). 
   As shown in  FIG. 1 , conventional software development tools  100  allow a programmer to view UML  102  while viewing source code  104 . The source code  104  is stored in a file, and a reverse engineering module  106  converts the source code  104  into a representation of the software project in a database or repository  108 . The software project comprises source code  104  in at least one file which, when compiled, forms a sequence of instructions to be run by the data processing system. The repository  108  generates the UML  102 . If any changes are made to the UML  102 , they are automatically reflected in the repository  108 , and a code generator  110  converts the representation in the repository  108  into source code  104 . Such software development tools  100 , however, do not synchronize the displays of the UML  102  and the source code  104 . Rather, the repository  108  stores the representation of the software project while the file stores the source code  104 . A modification in the UML  102  does not appear in the source code  104  unless the code generator  110  re-generates the source code  104  from the data in the repository  108 . When this occurs, the entire source code  104  is rewritten. Similarly, any modifications made to the source code  104  do not appear in the UML  102  unless the reverse engineering module  106  updates the repository  108 . As a result, redundant information is stored in the repository  108  and the source code  104 . In addition, rather than making incremental changes to the source code  104 , conventional software development tools  100  rewrite the overall source code  104  when modifications are made to the UML  102 , resulting in wasted processing time. This type of manual, large-grained synchronization requires either human intervention, or a “batch” style process to try to keep the two views (the UML  102  and the source code  104 ) in sync. Unfortunately, this approach, adopted by many tools, leads to many undesirable side-effects; such as desired changes to the source code being overwritten by the tool. A further disadvantage with conventional software development tools  100  is that they are designed to only work in a single programming language. Thus, a tool  100  that is designed for Java™ programs cannot be utilized to develop a program in C++. Moreover, it is not possible to track the changes made to the source code using conventional software development tools. Accordingly, unless the developer maintains detailed notes regarding the development of the source code, it is difficult to determine what modifications to the source code were attempted during its development. There is a need in the art for a tool that avoids the limitations of these conventional software development tools. 
   SUMMARY OF THE INVENTION 
   Methods and systems consistent with the present invention provide an improved software development tool which overcomes the limitations of conventional software development tools. The improved software development tool of the present invention allows a developer to track changes made to source code, and display the source code with these changes. Accordingly, the developer can recollect the modifications that were made to the source code during the development of the source code. 
   In accordance with methods consistent with the present invention, a method is provided in a data processing system for displaying versions of source code. Each version reflects an instance in an edit history. The method comprises the steps of storing indications of the edits to the source code, and displaying the versions of the source code with the indications of the edits. 
   In accordance with articles of manufacture consistent with the present invention, a computer-readable medium is provided. The computer-readable medium contains instructions for controlling a data processing system to perform a method. The data processing system has versions of source code. Each version reflects an instance in an edit history. The method comprises the steps of storing indications of the edits to the source code, and displaying the versions of the source code with the indications of the edits. 
   Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an implementation of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings, 
       FIG. 1  depicts a conventional software development tool; 
       FIG. 2  depicts an overview of a software development tool in accordance with the present invention; 
       FIG. 3  depicts a data structure of the language-neutral representation created by the software development tool of  FIG. 2 ; 
       FIG. 4  depicts representative source code; 
       FIG. 5  depicts the data structure of the language-neutral representation of the source code of  FIG. 4 ; 
       FIG. 6  depicts a data processing system suitable for practicing the present invention; 
       FIG. 7  depicts an architectural overview of the software development tool of  FIG. 2 ; 
       FIG. 8A  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a list of predefined criteria which the software development tool checks in the source code; 
       FIG. 8B  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays the definition of the criteria which the software development tool checks in the source code, and an example of source code which does not conform to the criteria; 
       FIG. 8C  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays an example of source code which conforms to the criteria which the software development tool checks in the source code; 
       FIG. 9  depicts a flow diagram of the steps performed by the software development tool depicted in  FIG. 2 ; 
       FIGS. 10A and 10B  depict a flow diagram illustrating the update model step of  FIG. 9 ; 
       FIG. 11  depicts a flow diagram of the steps performed by the software development tool in  FIG. 2  when creating a class; 
       FIG. 12  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a use case diagram of source code; 
       FIG. 13  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays both a class diagram and a textual view of source code; 
       FIG. 14  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a sequence diagram of source code; 
       FIG. 15  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a collaboration diagram of source code; 
       FIG. 16  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a statechart diagram of source code; 
       FIG. 17  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays an activity diagram of source code; 
       FIG. 18  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a component diagram of source code; 
       FIG. 19  depicts a user interface displayed by the software development tool depicted in  FIG. 2 , where the user interface displays a deployment diagram of source code; 
       FIG. 20  depicts a flow diagram of the steps performed by the software development tool depicted in  FIG. 2  to store the edit history of source code, in accordance with the present invention; and 
       FIGS. 21A–C  depict a flow diagram of the steps performed by the software development tool depicted in  FIG. 2  to sequentially displaying the source code with the indications of the edit history, in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Methods and systems consistent with the present invention provide an improved software development tool which displays versions of source code. Each version reflects an instance in an edit history, i.e., reflects the changes made to the source code. 
   As depicted in  FIG. 2 , source code  202  is being displayed in both a graphical form  204  and a textual form  206 . In accordance with methods and systems consistent with the present invention, the improved software development tool generates a transient meta model (TMM)  200  which stores a language-neutral representation of the source code  202 . The graphical  204  and textual  206  representations of the source code  202  are generated from the language-neutral representation in the TMM  200 . Although modifications made on the displays  204  and  206  may appear to modify the displays  204  and  206 , in actuality all modifications are made directly to the source code  202  via an incremental code editor (ICE)  208 , and the TMM  200  is used to generate the modifications in both the graphical  204  and the textual  206  views from the modifications to the source code  202 . 
   The improved software development tool provides simultaneous round-trip engineering, i.e., the graphical representation  204  is synchronized with the textual representation  206 . Thus, if a change is made to the source code  202  via the graphical representation  204 , the textual representation  206  is updated automatically. Similarly, if a change is made to the source code  202  via the textual representation  206 , the graphical representation  204  is updated to remain synchronized. There is no repository, no batch code generation, and no risk of losing code. 
   The data structure  300  of the language-neutral representation is depicted in  FIG. 3 . The data structure  300  comprises a Source Code Interface (SCI) model  302 , an SCI package  304 , an SCI class  306 , and an SCI member  308 . The SCI model  302  is the source code organized into packages. The SCI model  302  corresponds to a directory for a software project being developed by the user, and the SCI package  304  corresponds to a subdirectory. The software project comprises the source code in at least one file that is compiled to form a sequence of instructions to be run by a data processing system. The data processing system is discussed in detail below. As is well known in object-oriented programming, the class  306  is a category of objects which describes a group of objects with similar properties (attributes), common behavior (operations or methods), common relationships to other objects, and common semantics. The members  308  comprise attributes and/or operations. 
   For example, the data structure  500  for the source code  400  depicted in  FIG. 4  is depicted in  FIG. 5 . UserInterface  402  is defined as a package  404 . Accordingly, UserInterface  402  is contained in SCI package  502 . Similarly, Bank  406 , which is defined as a class  408 , is contained in SCI class  504 , and Name  410  and Assets  412 , which are defined as attributes (strings  414 ), are contained in SCI members  506 . Since these elements are in the same project, all are linked. The data structure  500  also identifies the language in which the source code is written  508 , e.g., the Java™ language. 
     FIG. 6  depicts a data processing system  600  suitable for practicing methods and systems consistent with the present invention. Data processing system  600  comprises a memory  602 , a secondary storage device  604 , an I/O device  606 , and a processor  608 . Memory  602  includes the improved software development tool  610 . The software development tool  610  is used to develop a software project  612 , and create the TMM  200  in the memory  602 . The project  612  is stored in the secondary storage device  604  of the data processing system  600 . One skilled in the art will recognize that data processing system  600  may contain additional or different components. 
   Although aspects of the present invention are described as being stored in memory, one skilled in the art will appreciate that these aspects can also be stored on or read from other types of computer-readable media, such as secondary storage devices, like hard disks, floppy disks or CD-ROM; or other forms of RAM or ROM either currently known or later developed. 
     FIG. 7  illustrates an architectural overview of the improved software development tool  610 . The tool  610  comprises a core  700 , an open application program interface (API)  702 , and modules  704 . The core  700  includes a parser  706  and an ICE  208 . The parser  706  converts the source code into the language-neutral representation in the TMM, and the ICE  208  converts the text from the displays into source code. There are three main packages composing the API  702 : Integrated Development Environment (IDE)  708 ; Read-Write Interface (RWI)  710 ; and Source Code Interface (SCI)  712 . Each package includes corresponding subpackages. As is well known in the art, a package is a collection of attributes, notifications, operations, or behaviors that are treated as a single module or program unit. 
   IDE  708  is the API  702  needed to generate custom outputs based on information contained in a model. It is a read-only interface, i.e., the user can extract information from the model, but not change the model. IDE  708  provides the functionality related to the model&#39;s representation in IDE  708  and interaction with the user. Each package composing the IDE group has a description highlighting the areas of applicability of this concrete package. 
   RWI  710  enables the user to go deeper into the architecture. Using RWI  710 , information can be extracted from and written to the models. RWI not only represents packages, classes and members, but it may also represent different diagrams (class diagrams, use case diagrams, sequence diagrams and others), links, notes, use cases, actors, states, etc. 
   SCI  712  is at the source code level, and allows the user to work with the source code almost independently of the language being used. 
   There are a variety of modules  704  in the software development tool  610  of the present invention. Some of the modules  704  access information to generate graphical and code documentation in custom formats, export to different file formats, or develop patterns. The software development tool also includes a quality assurance (QA) module which monitors the modifications to the source code and calculates the complexity metrics, i.e., the measurement of the program&#39;s performance or efficiency, to support quality assurance. The types of metrics calculated by the software development tool include basic metrics, cohesion metrics, complexity metrics, coupling metrics, Halstead metrics, inheritance metrics, maximum metrics, polymorphism metrics, and ratio metrics. Examples of these metrics with their respective definitions are identified in Tables 1–9 below. 
   
     
       
         
             
           
             
               TABLE 1 
             
           
          
             
                 
             
             
               Basics Metrics 
             
          
         
         
             
             
          
             
               Basic Metrics 
               Description 
             
             
                 
             
             
               Lines Of Code 
               Counts the number of code lines. 
             
             
               Number Of Attributes 
               Counts the number of attributes. If a class has 
             
             
                 
               a high number of attributes, it may be 
             
             
                 
               appropriate to divide it into subclasses. 
             
             
               Number Of Classes 
               Counts the number of classes. 
             
             
               Number Of Import 
               Counts the number of imported packages/ 
             
             
               Statements 
               classes. This measure can highlight excessive 
             
             
                 
               importing, and also can be used as a measure of 
             
             
                 
               coupling. 
             
             
               Number Of Members 
               Counts the number of members, i.e., attributes 
             
             
                 
               and operations. If a class has a high number of 
             
             
                 
               members, it may be appropriate to divide it into 
             
             
                 
               subclasses. 
             
             
               Number Of Operations 
               Counts the number of operations. If a class 
             
             
                 
               has a high number of operations, it may be 
             
             
                 
               appropriate to divide it into subclasses. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 2 
             
           
          
             
                 
             
             
               Cohesion Metrics 
             
          
         
         
             
             
          
             
               Cohesion Metrics 
               Description 
             
             
                 
             
             
               Lack Of Cohesion Of 
               Takes each pair of methods in the class and 
             
             
               Methods 1 
               determines the set of fields they each access. A 
             
             
                 
               low value indicates high coupling between 
             
             
                 
               methods, which indicates potentially low 
             
             
                 
               reusability and increased testing because many 
             
             
                 
               methods can affect the same attributes. 
             
             
               Lack Of Cohesion Of 
               Counts the percentage of methods that do not 
             
             
               Methods 2 
               access a specific attribute averaged over all 
             
             
                 
               attributes in the class. A high value of cohesion 
             
             
                 
               (a low lack of cohesion) implies that the class 
             
             
                 
               is well designed. 
             
             
               Lack Of Cohesion Of 
               Measures the dissimilarity of methods in a class 
             
             
               Methods 3 
               by attributes. A low value indicates good 
             
             
                 
               class subdivision, implying simplicity and 
             
             
                 
               high reusability. A high lack of cohesion 
             
             
                 
               increases complexity, thereby increasing the 
             
             
                 
               likelihood of errors during the development 
             
             
                 
               process. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 3 
             
           
          
             
                 
             
             
               Complexity Metrics 
             
          
         
         
             
             
          
             
               Complexity 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Attribute 
               Defined as the sum of each attribute&#39;s value in the class. 
             
             
               Complexity 
             
             
               Cyclomatic 
               Represents the cognitive complexity of the class. It counts 
             
             
               Complexity 
               the number of possible paths through an algorithm by 
             
             
                 
               counting the number of distinct regions on a flowgraph, i.e., 
             
             
                 
               the number of ‘if,’ ‘for’ and ‘while’ statements in the 
             
             
                 
               operation&#39;s body. 
             
             
               Number 
               Processes all of the methods and constructors, and counts 
             
             
               Of 
               the number of different remote methods called. A remote 
             
             
               Remote 
               method is defined as a method which is not declared in 
             
             
               Methods 
               either the class itself or its ancestors. 
             
             
               Response 
               Calculated as ‘Number of Local Methods’ + ‘Number of 
             
             
               For 
               Remote Methods.’ A class which provides a larger response 
             
             
               Class 
               set is considered to be more complex and requires more 
             
             
                 
               testing than one with a smaller overall design complexity. 
             
             
               Weighted 
               The sum of the complexity of all methods for a class, where 
             
             
               Methods 
               each method is weighted by its cyclomatic complexity. The 
             
             
               Per 
               number of methods and the complexity of the methods 
             
             
               Class 1 
               involved is a predictor of how much time and effort is 
             
             
                 
               required to develop and maintain the class. 
             
             
               Weighted 
               Measures the complexity of a class, assuming that a class 
             
             
               Methods 
               with more methods than another is more complex, and that 
             
             
               Per 
               a method with more parameters than another is also likely 
             
             
               Class 2 
               to be more complex. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 4 
             
           
          
             
                 
             
             
               Coupling Metrics 
             
          
         
         
             
             
          
             
               Coupling 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Coupling 
               Represents the number of other classes to which a class is 
             
             
               Between 
               coupled. Counts the number of reference types that are used 
             
             
               Objects 
               in attribute declarations, formal parameters, return types, 
             
             
                 
               throws declarations and local variables, and types from 
             
             
                 
               which attribute and method selections are made. 
             
             
                 
               Excessive coupling between objects is detrimental to 
             
             
                 
               modular design and prevents reuse. The more independent a 
             
             
                 
               class is, the easier it is to reuse it in another application. In 
             
             
                 
               order to improve modularity and promote encapsulation, 
             
             
                 
               inter-object class couples should be kept to a minimum. The 
             
             
                 
               larger the number of couples, the higher the sensitivity to 
             
             
                 
               changes in other parts of the design, and therefore 
             
             
                 
               maintenance is more difficult. A measure of coupling is 
             
             
                 
               useful to determine how complex the testing of various 
             
             
                 
               parts of a design is likely to be. The higher the inter-object 
             
             
                 
               class coupling, the more rigorous the testing needs to be. 
             
             
               Data 
               Counts the number of reference types used in the attribute 
             
             
               Abstraction 
               declarations. 
             
             
               Coupling 
             
             
               FanOut 
               Counts the number of reference types that are used in 
             
             
                 
               attribute declarations, formal parameters, return types, 
             
             
                 
               throws declarations and local variables. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 5 
             
           
          
             
                 
             
             
               Halstead Metrics 
             
          
         
         
             
             
          
             
               Halstead 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Halstead 
               This measure is one of the Halstead Software Science 
             
             
               Difficulty 
               metrics. It is calculated as (‘Number of Unique Operators’/ 
             
             
                 
               ‘Number of Unique Operands’) * (‘Number of Operands’/ 
             
             
                 
               ‘Number of Unique Operands’). 
             
             
               Halstead 
               This measure is one of the Halstead Software Science 
             
             
               Effort 
               metrics. It is calculated as ‘Halstead Difficulty’ * ‘Halstead 
             
             
                 
               Program Volume.’ 
             
             
               Halstead 
               This measure is one of the Halstead Software Science 
             
             
               Program 
               metrics. It is calculated as ‘Number of Operators’ + 
             
             
               Length 
               ‘Number of Operands.’ 
             
             
               Halstead 
               This measure is one of the Halstead Software Science 
             
             
               Program 
               metrics. It is calculated as ‘Number of Unique Operators’ + 
             
             
               Vocabulary 
               ‘Number of Unique Operands.’ 
             
             
               Halstead 
               This measure is one of the Halstead Software Science 
             
             
               Program 
               metrics. It is calculated as ‘Halstead Program Length’ * 
             
             
               Volume 
               Log2(‘Halstead Program Vocabulary’). 
             
             
               Number Of 
               This measure is used as an input to the Halstead Software 
             
             
               Operands 
               Science metrics. It counts the number of operands used in a 
             
             
                 
               class. 
             
             
               Number Of 
               This measure is used as an input to the Halstead Software 
             
             
               Operators 
               Science metrics. It counts the number of operators used in a 
             
             
                 
               class. 
             
             
               Number Of 
               This measure is used as an input to the Halstead Software 
             
             
               Unique 
               Science metrics. It counts the number of unique operands 
             
             
               Operands 
               used in a class. 
             
             
               Number Of 
               This measure is used as an input to the Halstead Software 
             
             
               Unique 
               Science metrics. It counts the number of unique operators 
             
             
               Operators 
               used in a class. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 6 
             
           
          
             
                 
             
             
               Inheritance Metrics 
             
          
         
         
             
             
          
             
               Inheritance 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Depth Of 
               Counts how far down the inheritance hierarchy a class or 
             
             
               Inheritance 
               interface is declared. High values imply that a class is quite 
             
             
               Hierarchy 
               specialized. 
             
             
               Number Of 
               Counts the number of classes which inherit from a 
             
             
               Child 
               particular class, i.e., the number of classes in the 
             
             
               Classes 
               inheritance tree down from a class. Non-zero value 
             
             
                 
               indicates that the particular class is being re-used. The 
             
             
                 
               abstraction of the class may be poor if there are too many 
             
             
                 
               child classes. It should also be stated that a high value of 
             
             
                 
               this measure points to the definite amount of testing 
             
             
                 
               required for each child class. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 7 
             
           
          
             
                 
             
             
               Maximum Metrics 
             
          
         
         
             
             
          
             
               Maximum 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Maximum 
               Counts the maximum depth of ‘if,’ ‘for’ and ‘while’ 
             
             
               Number Of 
               branches in the bodies of methods. Logical units with a 
             
             
               Levels 
               large number of nested levels may need implementation 
             
             
                 
               simplification and process improvement because groups that 
             
             
                 
               contain more than seven pieces of information are 
             
             
                 
               increasingly harder for people to understand in problem 
             
             
                 
               solving. 
             
             
               Maximum 
               Displays the maximum number of parameters among all 
             
             
               Number Of 
               class operations. Methods with many parameters tend to be 
             
             
               Parameters 
               more specialized and, thus, are less likely to be reusable. 
             
             
               Maximum 
               Counts the maximum size of the operations for a class. 
             
             
               Size Of 
               Method size is determined in terms of cyclomatic 
             
             
               Operation 
               complexity, i.e., the number of ‘if,’ ‘for’ and ‘while’ 
             
             
                 
               statements in the operation&#39;s body. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 8 
             
           
          
             
                 
             
             
               Polymorphism Metrics 
             
          
         
         
             
             
          
             
               Polymorphism 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Number Of 
               Counts the number of operations added by a class. A 
             
             
               Added 
               large value of this measure indicates that the functionality 
             
             
               Methods 
               of the given class becomes increasingly distinct from that 
             
             
                 
               of the parent classes. In this case, it should be considered 
             
             
                 
               whether this class genuinely should be inheriting from 
             
             
                 
               the parent, or if it could be broken down into several 
             
             
                 
               smaller classes. 
             
             
               Number Of 
               Counts the number of inherited operations which a class 
             
             
               Overridden 
               overrides. Classes without parents are not processed. 
             
             
               Methods 
               High values tend to indicate design problems, i.e., 
             
             
                 
               subclasses should generally add to and extend the 
             
             
                 
               functionality of the parent classes rather than overriding 
             
             
                 
               them. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 9 
             
           
          
             
                 
             
             
               Ratio Metrics 
             
          
         
         
             
             
          
             
               Ratio 
                 
             
             
               Metrics 
               Description 
             
             
                 
             
             
               Comment 
               Counts the ratio of comments to total lines of code 
             
             
               Ratio 
               including comments. 
             
             
               Percentage 
               Counts the percentage of package members in a class. 
             
             
               Of Package 
             
             
               Members 
             
             
               Percentage 
               Counts the percentage of private members in a class. 
             
             
               Of Private 
             
             
               Members 
             
             
               Percentage 
               Counts the percentage of protected members in a class. 
             
             
               Of Protected 
             
             
               Members 
             
             
               Percentage 
               Counts the proportion of vulnerable members in a class. A 
             
             
               Of Public 
               large proportion of such members means that the class has 
             
             
               Members 
               high potential to be affected by external classes and means 
             
             
                 
               that increased efforts will be needed to test such a class 
             
             
                 
               thoroughly. 
             
             
               True 
               Counts the ratio of comments to total lines of code 
             
             
               Comment 
               excluding comments. 
             
             
               Ratio 
             
             
                 
             
          
         
       
     
   
   The QA module also provides audits, i.e., the module checks for conformance to predefined or user-defined styles. The types of audits provided by the module include coding style, critical errors, declaration style, documentation, naming style, performance, possible errors and superfluous content. Examples of these audits with their respective definitions are identified in Tables 10–17 below. 
   
     
       
         
             
           
             
               TABLE 10 
             
           
          
             
                 
             
             
               Coding Style Audits 
             
          
         
         
             
             
          
             
               Coding Style 
                 
             
             
               Audits 
               Description 
             
             
                 
             
             
               Access Of 
               Static members should be referenced through class names 
             
             
               Static 
               rather than through objects. 
             
             
               Members 
             
             
               Through 
             
             
               Objects 
             
             
               Assignment 
               Formal parameters should not be assigned. 
             
             
               To Formal 
             
             
               Parameters 
             
             
               Complex 
               Checks for the occurrence of multiple assignments and 
             
             
               Assignment 
               assignments to variables within the same expression. 
             
             
                 
               Complex assignments should be avoided since they 
             
             
                 
               decrease program readability. 
             
             
               Don&#39;t Use 
               The negation operator slows down the readability of the 
             
             
               the Negation 
               program. Thus, it is recommended that it not be used 
             
             
               Operator 
               frequently. 
             
             
               Frequently 
             
             
               Operator ‘?:’ 
               The operator ‘?:’ makes the code harder to read than the 
             
             
               May Not Be 
               alternative form with an if-statement. 
             
             
               Used 
             
             
               Provide 
               Checks if the third argument of the ‘for’-statement is 
             
             
               Incremental 
               missing. 
             
             
               In For- 
             
             
               Statement or 
             
             
               use while- 
             
             
               statement 
             
             
               Replacement 
               Demand import-declarations must be replaced by a list of 
             
             
               For Demand 
               single import-declarations that are actually imported into 
             
             
               Imports 
               the compilation unit. In other words, import-statements 
             
             
                 
               may not end with an asterisk. 
             
             
               Use 
               Use the abbreviated assignment operator in order to write 
             
             
               Abbreviated 
               programs more rapidly. Also some compilers run faster 
             
             
               Assignment 
               with the abbreviated assignment operator. 
             
             
               Operator 
             
             
               Use ‘this’ 
               Tries to make the developer use ‘this’ explicitly when 
             
             
               Explicitly To 
               trying to access class members. Using the same class 
             
             
               Access Class 
               member names with parameter names often makes what the 
             
             
               Members 
               developer is referring to unclear. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 11 
             
           
          
             
                 
             
             
               Critical Errors Audits 
             
          
         
         
             
             
          
             
               Critical Errors 
                 
             
             
               Audits 
               Description 
             
             
                 
             
             
               Avoid Hiding 
               Detects when attributes declared in child classes hide 
             
             
               Inherited 
               inherited attributes. 
             
             
               Attributes 
             
             
               Avoid Hiding 
               Detects when inherited static operations are hidden by 
             
             
               Inherited 
               child classes. 
             
             
               Static Methods 
             
             
               Command 
               Prevents methods that return a value from a modifying 
             
             
               Query 
               state. The methods used to query the state of an object 
             
             
               Separation 
               must be different from the methods used to perform 
             
             
                 
               commands (change the state of the object). 
             
             
               Hiding Of 
               Declarations of names should not hide other declarations 
             
             
               Names 
               of the same name. 
             
             
               Inaccessible 
               Overload resolution only considers constructors and 
             
             
               Constructor Or 
               methods that are visible at the point of the call. If, 
             
             
               Method 
               however, all the constructors and methods were 
             
             
               Matches 
               considered, there may be more matches. This rule is 
             
             
                 
               violated in this case. 
             
             
                 
               Imagine that ClassB is in a different package than 
             
             
                 
               ClassA. Then the allocation of ClassB violates this rule 
             
             
                 
               since the second constructor is not visible at the point of 
             
             
                 
               the allocation, but it still matches the allocation (based 
             
             
                 
               on signature). Also the call to open in ClassB violates 
             
             
                 
               this rule since the second and the third declarations of 
             
             
                 
               open are not visible at the point of the call, but it still 
             
             
                 
               matches the call (based on signature). 
             
             
               Multiple 
               Multiple declarations with the same name must not be 
             
             
               Visible 
               simultaneously visible except for overloaded methods. 
             
             
               Declarations 
             
             
               With Same 
             
             
               Name 
             
             
               Overriding a 
               Checks for abstract methods overriding non-abstract 
             
             
               Non-Abstract 
               methods in a subclass. 
             
             
               Method With 
             
             
               an Abstract 
             
             
               Method 
             
             
               Overriding a 
               A subclass should not contain a method with the same 
             
             
               Private Method 
               name and signature as in a superclass if these methods 
             
             
                 
               are declared to be private. 
             
             
               Overloading 
               A superclass method may not be overloaded within a 
             
             
               Within a 
               subclass unless all overloading in the superclass are also 
             
             
               Subclass 
               overridden in the subclass. It is very unusual for a 
             
             
                 
               subclass to be overloading methods in its superclass 
             
             
                 
               without also overriding the methods it is overloading. 
             
             
                 
               More frequently this happens due to inconsistent changes 
             
             
                 
               between the superclass and subclass - i.e., the intention 
             
             
                 
               of the user is to override the method in the superclass, 
             
             
                 
               but due to the error, the subclass method ends up 
             
             
                 
               overloading the superclass method. 
             
             
               Use of Static 
               Non-final static attributes should not be used in 
             
             
               Attribute for 
               initializations of attributes. 
             
             
               Initialization 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 12 
             
           
          
             
                 
             
             
               Declaration Style Audits 
             
          
         
         
             
             
          
             
               Declaration 
                 
             
             
               Style Audits 
               Description 
             
             
                 
             
             
               Badly 
               Array declarators must be placed next to the type descriptor 
             
             
               Located 
               of their component type. 
             
             
               Array 
             
             
               Declarators 
             
             
               Constant 
               Private attributes that never get their values changed must 
             
             
               Private 
               be declared final. By explicitly declaring them in such a 
             
             
               Attributes 
               way, a reader of the source code get some information of 
             
             
               Must Be 
               how the attribute is supposed to be used. 
             
             
               Final 
             
             
               Constant 
               Local variables that never get their values changed must be 
             
             
               Variables 
               declared final. By explicitly declaring them in such a way, a 
             
             
               Must Be 
               reader of the source code obtains information about how the 
             
             
               Final 
               variable is supposed to be used. 
             
             
               Declare 
               Several variables (attributes and local variables) should not 
             
             
               Variables In 
               be declared in the same statement. 
             
             
               One 
             
             
               Statement 
             
             
               Each 
             
             
               Instantiated 
               This rule recommends making all instantiated classes final. 
             
             
               Classes 
               It checks classes which are present in the object model. 
             
             
               Should Be 
               Classes from search/classpath are ignored. 
             
             
               Final 
             
             
               List All 
               Enforces a standard to improve readability. Methods/data in 
             
             
               Public And 
               your class should be ordered properly. 
             
             
               Package 
             
             
               Members 
             
             
               First 
             
             
               Order Of 
               Checks for correct ordering of modifiers. For classes, this 
             
             
               Appearance 
               includes visibility (public, protected or private), abstract, 
             
             
               Of Modifiers 
               static, final. For attributes, this includes visibility (public, 
             
             
                 
               protected or private), static, final, transient, volatile. For 
             
             
                 
               operations, this includes visibility (public, protected or 
             
             
                 
               private), abstract, static, final, synchronized, native. 
             
             
               Put the Main 
               Tries to make the program comply with various coding 
             
             
               Function 
               standards regarding the form of the class definitions. 
             
             
               Last 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 13 
             
           
          
             
                 
             
             
               Documentation Audits 
             
          
         
         
             
             
          
             
               Documentation 
                 
             
             
               Audits 
               Description 
             
             
                 
             
             
               Bad Tag In 
               This rule verifies code against accidental use of improper 
             
             
               JavaDoc 
               JavaDoc tags. 
             
             
               Comments 
             
             
               Distinguish 
               Checks whether the JavaDoc comments in your program 
             
             
               Between 
               ends with ‘**/’ and ordinary C-style ones with ‘*/.’ 
             
             
               JavaDoc And 
             
             
               Ordinary 
             
             
               Comments 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 14 
             
           
          
             
                 
             
             
               Naming Style Audits 
             
          
         
         
             
             
          
             
               Naming Style 
                 
             
             
               Audits 
               Description 
             
             
                 
             
             
               Class Name 
               Checks whether top level classes or interfaces have the 
             
             
               Must Match 
               same name as the file in which they reside. 
             
             
               Its File Name 
             
             
               Group 
               Enforces standard to improve readability. 
             
             
               Operations 
             
             
               With Same 
             
             
               Name Together 
             
             
               Naming 
               Takes a regular expression and item name and reports all 
             
             
               Conventions 
               occurrences where the pattern does not match the 
             
             
                 
               declaration. 
             
             
               Names Of 
               Names of classes which inherit from Exception should 
             
             
               Exception 
               end with Exception. 
             
             
               Classes 
             
             
               Use 
               One-character local variable or parameter names should 
             
             
               Conventional 
               be avoided, except for temporary and looping variables, 
             
             
               Variable 
               or where a variable holds an undistinguished value of a 
             
             
               Names 
               type. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 15 
             
           
          
             
                 
             
             
               Performance Audits 
             
          
         
         
             
             
          
             
               Performance 
                 
             
             
               Audits 
               Description 
             
             
                 
             
             
               Avoid 
               This rule recommends declaring local variables outside the 
             
             
               Declaring 
               loops since declaring variables inside the loop is less 
             
             
               Variables 
               efficient. 
             
             
               Inside Loops 
             
             
               Append To 
               Performance enhancements can be obtained by replacing 
             
             
               String 
               String operations with StringBuffer operations if a String 
             
             
               Within a 
               object is appended within a loop. 
             
             
               Loop 
             
             
               Complex 
               Avoid using complex expressions as repeat conditions 
             
             
               Loop 
               within loops. 
             
             
               Expressions 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 16 
             
           
          
             
                 
             
             
               Possible Error Audits 
             
          
         
         
             
             
          
             
               Possible 
                 
             
             
               Error Audits 
               Description 
             
             
                 
             
             
               Avoid Public 
               Declare the attributes either private or protected, and 
             
             
               And Package 
               provide operations to access or change them. 
             
             
               Attributes 
             
             
               Avoid 
               Avoid statements with empty body. 
             
             
               Statements 
             
             
               With Empty 
             
             
               Body 
             
             
               Assignment 
               ‘For’-loop variables should not be assigned. 
             
             
               To For-Loop 
             
             
               Variables 
             
             
               Don&#39;t Compare 
               Avoid testing for equality of floating point numbers since 
             
             
               Floating 
               floating-point numbers that should be equal are not 
             
             
               Point Types 
               always equal due to rounding problems. 
             
             
               Enclosing 
               The statement of a loop must always be a block. The 
             
             
               Body Within 
               ‘then’ and ‘else’ parts of ‘if’-statements must always be 
             
             
               a Block 
               blocks. This makes it easier to add statements without 
             
             
                 
               accidentally introducing bugs in case the developer 
             
             
                 
               forgets to add braces. 
             
             
               Explicitly 
               Explicitly initialize all variables. The only reason not to 
             
             
               Initialize All 
               initialize a variable is where it&#39;s declared is if the initial 
             
             
               Variables 
               value depends on some computation occurring first. 
             
             
               Method 
               Calling of super.finalize() from finalize() is good practice 
             
             
               finalize() 
               of programming, even if the base class doesn&#39;t define the 
             
             
               Doesn&#39;t Call 
               finalize() method. This makes class implementations less 
             
             
               super.finalize() 
               dependent on each other. 
             
             
               Mixing Logical 
               An expression containing multiple logical operators 
             
             
               Operators 
               should be parenthesized properly. 
             
             
               Without 
             
             
               Parentheses 
             
             
               No 
               Use of assignment within conditions makes the source 
             
             
               Assignments In 
               code hard to understand. 
             
             
               Conditional 
             
             
               Expressions 
             
             
               Use ‘equals’ 
               The ‘==’ operator used on strings checks if two string 
             
             
               Instead Of ‘==’ 
               objects are two identical objects. In most situations, 
             
             
                 
               however, one likes to simply check if two strings have 
             
             
                 
               the same value. In these cases, the ‘equals’ method 
             
             
                 
               should be used. 
             
             
               Use ‘L’ Instead 
               It is better to use uppercase ‘L’ to distinguish the letter 
             
             
               Of ‘l’ at the end 
               ‘l’ from the number ‘1.’ 
             
             
               of integer 
             
             
               constant 
             
             
               Use Of the 
               The ‘synchronized’ modifier on methods can sometimes 
             
             
               ‘synchronized’ 
               cause confusion during maintenance as well as during 
             
             
               Modifier 
               debugging. This rule therefore recommends against using 
             
             
                 
               this modifier, and instead recommends using 
             
             
                 
               ‘synchronized’ statements as replacements. 
             
             
                 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 17 
             
           
          
             
                 
             
             
               Superfluous Content Audits 
             
          
         
         
             
             
          
             
               Superfluous 
                 
             
             
               Content Audits 
               Description 
             
             
                 
             
             
               Duplicate 
               There should be at most one import declaration that 
             
             
               Import 
               imports a particular class/package. 
             
             
               Declarations 
             
             
               Don&#39;t Import 
               No classes or interfaces need to be imported from the 
             
             
               the Package the 
               package to which the source code file belongs. 
             
             
               Source File 
               Everything in that package is available without explicit 
             
             
               Belongs To 
               import statements. 
             
             
               Explicit Import 
               Explicit import of classes from the package ‘java.lang’ 
             
             
               Of the 
               should not be performed. 
             
             
               java.lang 
             
             
               Classes 
             
             
               Equality 
               Avoid performing equality operations on Boolean 
             
             
               Operations On 
               operands. ‘True’ and ‘false’ literals should not be used 
             
             
               Boolean 
               in conditional clauses. 
             
             
               Arguments 
             
             
               Imported Items 
               It is not legal to import a class or an interface and never 
             
             
               Must Be Used 
               use it. This rule checks classes and interfaces that are 
             
             
                 
               explicitly imported with their names - that is not with 
             
             
                 
               import of a complete package, using an asterisk. If 
             
             
                 
               unused class and interface imports are omitted, the 
             
             
                 
               amount of meaningless source code is reduced - thus the 
             
             
                 
               amount of code to be understood by a reader is 
             
             
                 
               minimized. 
             
             
               Unnecessary 
               Checks for the use of type casts that are not necessary. 
             
             
               Casts 
             
             
               Unnecessary 
               Verifies that the runtime type of the left-hand side 
             
             
               ‘instanceof’ 
               expression is the same as the one specified on the 
             
             
               Evaluations 
               right-hand side. 
             
             
               Unused Local 
               Local variables and formal parameter declarations must 
             
             
               Variables And 
               be used. 
             
             
               Formal 
             
             
               Parameters 
             
             
               Use Of 
               The modifier ‘abstract’ is considered obsolete and should 
             
             
               Obsolete 
               not be used. 
             
             
               Interface 
             
             
               Modifier 
             
             
               Use Of 
               All interface operations are implicitly public and abstract. 
             
             
               Unnecessary 
               All interface attributes are implicitly public, final and 
             
             
               Interface 
               static. 
             
             
               Member 
             
             
               Modifiers 
             
             
               Unused Private 
               An unused class member might indicate a logical flaw in 
             
             
               Class Member 
               the program. The class declaration has to be reconsidered 
             
             
                 
               in order to determine the need of the unused member(s). 
             
             
                 
             
          
         
       
     
   
   If the QA module determines that the source code does not conform, an error message is provided to the developer. For example, as depicted in  FIG. 8A , the software development tool checks for a variety of coding styles  800 . If the software development tool were to check for “Access Of Static Members Through Objects”  802 , it would verify whether static members are referenced through class names rather than through objects  804 . Further, as depicted in  FIG. 8B , if the software development tool were to check for “Complex Assignment”  806 , the software development tool would check for the occurrence of multiple assignments and assignments to variables within the same expression to avoid complex assignments since these decrease program readability  808 . An example of source code having a complex assignment  810  and source code having a non-complex assignment  812  are depicted in  FIGS. 8B and 8C , respectively. The QA module of the software development tool monitors the source code for other syntax errors well known in the art, as described above, and provides an error message if any such errors are detected. 
   The improved software development tool of the present invention is used to develop source code in a project. The project comprises a plurality of files and the source code of one of the plurality of files is written in a given language. The software development tool determines the language of the source code of the file, converts the source code from the language into a language-neutral representation, uses the language-neutral representation to textually display the source code of the file in the language, and uses the language-neutral representation to display a graphical representation of at least a portion of the project. The source code and the graphical representation are displayed simultaneously. 
   The improved software development tool of the present invention is also used to develop source code. The software development tool receives an indication of a selected language for the source code, creates a file to store the source code in the selected language, converts the source code from the selected language into a language-neutral representation, uses the language-neutral representation to display the source code of the file, and uses the language-neutral representation to display a graphical representation of the file. Again, the source code and the graphical representation are displayed simultaneously. 
   Moreover, if the source code in the file is modified, the modified source code and a graphical representation of at least a portion of the modified source code are displayed simultaneously. The QA module of the software development tool provides an error message if the modification does not conform to predefined or user-defined styles, as described above. The modification to the source code may be received from the display of the source code, the display of the graphical representation of the project, or via some other independent software to modify the code. The graphical representation of the project may be in Unified Modeling Language; however, one skilled in the art will recognize that other graphical representations of the source code may be displayed. Further, although the present invention is described and shown using the various views of the UML, one of ordinary skill in the art will recognize that other views may be displayed. 
     FIG. 9  depicts a flow diagram of the steps performed by the software development tool to develop a project in accordance with the present invention. As previously stated, the project comprises a plurality of files. The developer either uses the software development tool to open a file which contains existing source code, or to create a file in which the source code will be developed. If the software development tool is used to open the file, determined in step  900 , the software development tool initially determines the programming language in which the code is written (step  902 ). The language is identified by the extension of the file, e.g., “java” identifies source code written in the Java™ language, while “.cpp” identifies source code written in C++. The software development tool then obtains a template for the current programming language, i.e., a collection of generalized definitions for the particular language that can be used to build the data structure (step  904 ). For example, the definition of a new Java™ class contains a default name, e.g., “Class1,” and the default code, “public class Class1 { }.” Such templates are well known in the art. For example, the “Microsoft Foundation Class Library” and the “Microsoft Word Template For Business Use Case Modeling” are examples of standard template libraries from which programmers can choose individual template classes. The software development tool uses the template to parse the source code (step  906 ), and create the data structure (step  908 ). After creating the data structure or if there is no existing code, the software development tool awaits an event, i.e., a modification or addition to the source code by the developer (step  910 ). If an event is received and the event is to close the file (step  912 ), the file is saved (step  914 ) and closed (step  916 ). Otherwise, the software development tool performs the event (step  918 ), i.e., the tool makes the modification. The software development tool then updates the TMM or model (step  920 ), as discussed in detail below, and updates both the graphical and the textual views (step  922 ). 
     FIGS. 10A and 10B  depict a flow diagram illustrating the update model step of  FIG. 9 . The software development tool selects a file from the project (step  1000 ), and determines whether the file is new (step  1002 ), whether the file has been updated (step  1004 ), or whether the file has been deleted (step  1006 ). If the file is new, the software development tool adds the additional symbols from the file to the TMM (step  1008 ). To add the symbol to the TMM, the software development tool uses the template to parse the symbol to the TMM. If the file has been updated, the software development tool updates the symbols in the TMM (step  1010 ). Similar to the addition of a symbol to the TMM, the software development tool uses the template to parse the symbol to the TMM. If the file has been deleted, the software development tool deletes the symbols in the TMM (step  1012 ). The software development tool continues this analysis for all files in the project. After all files are analyzed (step  1014 ), any obsolete symbols in the TMM (step  1016 ) are deleted (step  1018 ). 
     FIG. 11  depicts a flow diagram illustrating the performance of an event, specifically the creation of a class, in accordance with the present invention. After identifying the programming language (step  1100 ), the software development tool obtains a template for the language (step  1102 ), creates a source code file in the project directory (step  1104 ), and pastes the template onto the TMM (step  1106 ). The project directory corresponds to the SCI model  302  of  FIG. 3 . Additional events which a developer may perform using the software development tool include the creation, modification or deletion of packages, projects, attributes, interfaces, links, operations, and the closing of a file. 
   The software development tool is collectively broken into three views of the application: the static view, the dynamic view, and the functional view. The static view is modeled using the use-case and class diagrams. A use case diagram  1200 , depicted in  FIG. 12 , shows the relationship among actors  1202  and use cases  1204  within the system  1206 . A class diagram  1300 , depicted in  FIG. 13  with its associated source code  1302 , on the other hand, includes classes  1304 , interfaces, packages and their relationships connected as a graph to each other and to their contents. 
   The dynamic view is modeled using the sequence, collaboration and statechart diagrams. As depicted in  FIG. 14 , a sequence diagram  1400  represents an interaction, which is a set of messages  1402  exchanged among objects  1404  within a collaboration to effect a desired operation or result. In a sequence diagram  1400 , the vertical dimension represents time and the horizontal dimension represents different objects. A collaboration diagram  1500 , depicted in  FIG. 15 , is also an interaction with messages  1502  exchanged among objects  1504 , but it is also a collaboration, which is a set of objects  1504  related in a particular context. Contrary to sequence diagrams  1400  ( FIG. 14 ), which emphasize the time ordering of messages along the vertical axis, collaboration diagrams  1500  ( FIG. 15 ) emphasize the structural organization of objects. 
   A statechart diagram  1600  is depicted in  FIG. 16 . The statechart diagram  1600  includes the sequences of states  1602  that an object or interaction goes through during its life in response to stimuli, together with its responses and actions. It uses a graphic notation that shows states of an object, the events that cause a transition from one state to another, and the actions that result from the transition. 
   The functional view can be represented by activity diagrams  1700  and more traditional descriptive narratives such as pseudocode and minispecifications. An activity diagram  1700  is depicted in  FIG. 17 , and is a special case of a state diagram where most, if not all, of the states are action states  1702  and where most, if not all, of the transitions are triggered by completion of the actions in the source states. Activity diagrams  1700  are used in situations where all or most of the events represent the completion of internally generated actions. 
   There is also a fourth view mingled with the static view called the architectural view. This view is modeled using package, component and deployment diagrams. Package diagrams show packages of classes and the dependencies among them. Component diagrams  1800 , depicted in  FIG. 18 , are graphical representations of a system or its component parts. Component diagrams  1800  show the dependencies among software components, including source code components, binary code components and executable components. As depicted in  FIG. 19 , Deployment diagrams  1900  are used to show the distribution strategy for a distributed object system. Deployment diagrams  1900  show the configuration of run-time processing elements and the software components, processes and objects that live on them. 
   Although discussed in terms of class diagrams, one skilled in the art will recognize that the software development tool of the present invention may support these and other graphical views. 
   The improved software development tool of the present invention is used to display versions of source code. Each version is an instance in an edit history. The software development tool determines a language of the source code, stores indications of the edits to the source code, converts the source code with the indications of the edits from the language into a language-neutral representation, uses the language-neutral representation to display the source code in the language with the indications of the edits, and uses the language-neutral representation to display the corresponding graphical representation of the source code with the indications of the edits. The rate at which the source code with the indications of the edits is displayed is adjustable. Moreover, the source code with the indications of the edits may be displayed sequentially or in reverse order. 
     FIG. 20  depicts a flow diagram of the steps performed by the software development tool to store the edit history of source code. After the source code has been modified (step  2000 ), the software development tool saves the edits to the source code into the secondary storage (step  2002 ). After all edits have been made (step  2004 ), the software development tool saves the source code into the secondary storage (step  2006 ). 
   The steps performed by the software development tool to sequentially display the source code with the edit history is depicted in  FIGS. 21A–C . The software development tool retrieves the source code (step  2100 ), identifies the programming language of the source code (step  2102 ), and obtains the template for the current programming language (step  2104 ). The software development tool then parses the source code (step  2106 ) and creates the data structure (step  2108 ). The software development tool retrieves the edit history, i.e., all of the edits which were stored for the source code (step  2110 ), and the user chooses a rate of displaying the source code (step  2112 ), thus setting the time period (step  2114 ). The user chooses whether to display the source code in the forward mode or in the reverse mode (step  2116 ). 
   In the forward mode shown in  FIG. 21B , the software development tool removes all edits to the source code (step  2118 ) and updates the model (step  2120 ). The software development tool pauses for the time period determined by the rate at which the source code is displayed (step  2122 ), and for each edit (step  2124 ), the software development tool applies the edit to the source code (step  2126 ) before updating the model (step  2128 ). If the user chooses to adjust the rate of the display (step  2130 ), the time period is adjusted accordingly (step  2132 ). The process then continues with the next edit (step  2134 ). 
   In the reverse mode depicted in  FIG. 21C , the software development tool pauses for the time period (step  2136 ), and for each edit (step  2138 ), the software development tool removes the edit from the source code (step  2140 ) before updating the model (step  2142 ). If the user chooses to adjust the rate of the display (step  2144 ), the software development tool adjusts the time period accordingly (step  2146 ). The process then continues with the next edit (step  2148 ). 
   While various embodiments of the application have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.