Patent Publication Number: US-8533692-B2

Title: Dynamic software enhancement parameters

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     U.S. patent application Ser. No. 11/323,042, FOR DYNAMIC SOFTWARE ENHANCEMENT, filed Dec. 30, 2005. 
     BACKGROUND 
     The present invention relates to dynamic software enhancement, and more particularly to enhancing software functionality without directly modifying the underlying source code. 
     Software obtained from software vendors, consultants or even different parties within the same organization or company can be modified in order to customize the software to suit a particular need or purpose. However, when upgrades or patches to the software are installed, modifications to the software can be lost. This requires that customizations be reintegrated after an upgrade to the software. This is a manual, time consuming process that is prone to errors, especially if the modifications are extensive. 
     SUMMARY OF THE INVENTION 
     The present invention provides methods and apparatus, including computer program products, that implement techniques for dynamic software enhancement. 
     In one general aspect, the techniques feature accepting user input defining a first additional parameter to a first source code component, the first source code component not being modified. Accepting user input defining a first modification to the first source code component, the first modification dependent on the first additional parameter, and the source code component not being modified. Incorporating into a second source code component the first source code component and an expression of the first additional parameter and the first modification, the second source code component being separate from the first source code component. And creating a compiled program using the second source code component. 
     The invention can be implemented to include one or more of the following advantageous features. The first source code component is a function or method definition. The first additional parameter has a type that is one of importing, exporting or changing. The first modification is at a first enhancement point. The first enhancement point is one of the following locations in the first source code component: function or method entry; function or method exit; or exceptional function or method exit. The first additional parameter is optional. Invoking the first source code component with the first additional parameter. 
     The invention can be implemented to realize one or more of the following advantages. It is possible to have more than one enhancement of source code and more than one implementation of an enhancement. Because enhancements are separate from the source code they enhance, enhancements can be documented and managed separately. An enhancement can be disabled. An enhancement can itself be enhanced in a higher software layer. Enhancement points are not explicitly defined in the source code they pertain to. An enhancement can add one or more parameters to a function or method definition. An enhancement can add additional source code to a function or method definition. 
     One implementation of the invention provides all of the above advantages. 
     Details of one or more implementations of the invention are set forth in the accompanying drawings and in the description below. Further features, aspects, and advantages of the invention will become apparent from the description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of source code showing illustrative modification points. 
         FIG. 2  illustrates possible enhancement points for a source code component. 
         FIG. 3  illustrates execution of an enhanced source code component. 
         FIG. 4  is a diagram of a source code component modification system. 
         FIG. 5  is an expression of a modification to a source code component. 
         FIG. 6  is a flow diagram illustrating a method of enhancing a source code component. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     The present invention relates to dynamic software enhancement, and more particularly to enhancing software without directly modifying the underlying source code. 
     As shown in  FIG. 1  and by way of illustration, source code  100  is a function definition for dividing a first number Z 1  by a second number N 1  in the ABAP (Advanced Business Application Programming) programming language, which is available from SAP AG of Walldorf, Germany. Users may desire to modify this function in various ways to better suit their needs. For example, a user may add one or more parameters  102  at location  102   a . Or a user may add code ( 104 ,  108 ) to be invoked the beginning of the function (location  104   a ) or on return from the function (location  108   a ). Since this function raises an exception on division by zero, the user may also add an exception handler  106  at location  106   a . Alternatively, the user may wish to replace the entire body of the function altogether. However, modifying the source code  100  creates problems if the source code is being maintained by an entity other than the user, such as a software vendor. Each time the source code  100  is updated by the entity, the user&#39;s changes must be added anew. This can be time consuming and error prone. 
       FIG. 2  illustrates possible enhancement points for a source code component  200 . One or more modifications to a source code component can be incorporated with the source code component at enhancement points, but without modifying the source code component. A source code component incorporates source code such as a function, procedure or method definition or declaration. A modification represents a change to be incorporated into a copy of a source code component. By way of illustration, the copy can be a copy of the source code component. Or the copy can be a translation of the source code component to another form, e.g., an object code or intermediate language form. A modification can be represented as source code, editing directives, metadata, translated source code, or a combination of these. Integration of a modification to a component can include inserting the modification into the copy, deleting code from the copy, replacing code in the copy with the modification, or a combination of these. 
     Although this illustration is provided for the ABAP programming language, other programming languages are possible including combinations of languages. In this illustration, enhancement of a class method is illustrated; however, the same integrations are possible for functions. A class named FOO  218  defines a method named BAR  220 . The BAR method  220  has two parameters: an importing parameter number which is an integer, and an exporting parameter result which is a packed number having two decimal places. One or more additional parameters can be incorporated at enhancement point  201  for importing type parameters, at enhancement point  204  for exporting type parameters, and at enhancement point  206  for changing type parameters. 
     One or more modifications are incorporated into a copy at one or more enhancement points to create an enhanced component. An enhancement point is an implicit location in the source code component (and hence the copy) where modifications can be incorporated. That is, enhancement points are not specifically identified in the source code component. More than one modification can be incorporated at a given enhancement point. In one implementation and by way of example, a modification is classified according to an enhancement point, as described in Table 1. Other enhancement points are possible. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 MODIFICATION 
                 ENHANCEMENT POINT 
               
               
                   
               
             
            
               
                 Overwrite-exit 
                 Start of function/method. Replaces the entire body 
               
               
                   
                 of a function/method with the modification. 
               
               
                 Pre-Exit 
                 Start of function/method, before original function/ 
               
               
                   
                 method code is executed. 
               
               
                 Post-Exit 
                 Normal exit point from a function/method. 
               
               
                 Cleanup-Exit 
                 Abnormal exit point from a function/method (e.g., 
               
               
                   
                 upon reaching a “raise” statement in the 
               
               
                   
                 ABAP language). 
               
               
                 Catch-Exit 
                 Exception handler used to catch a set of specific 
               
               
                   
                 exceptions or all exceptions for a function/method. 
               
               
                 Parameter 
                 One or more additional parameters are specified 
               
               
                   
                 for a function/method (e.g., at the end of the 
               
               
                   
                 importing, exporting, changing, and tables section 
               
               
                   
                 of a function/method definition in the ABAP 
               
               
                   
                 programming language). In one implementation, 
               
               
                   
                 an added parameter is an optional parameter. That 
               
               
                   
                 is, the caller of a method of function does not 
               
               
                   
                 need to specify the parameter. The one or more 
               
               
                   
                 additional parameters can be used by modifications. 
               
               
                   
                 If a modification uses an additional parameter, 
               
               
                   
                 the modification is dependent on the additional 
               
               
                   
                 parameter. 
               
               
                   
               
            
           
         
       
     
     The implementation of the BAR method is indicated by source code section  222 . The method defines local variables OREF, which is a reference to type CX_ROOT, and MESSAGE, which is a string. There is a “try” block indicated by source code section  224 . A “try” block allows exceptions handlers to be specified for exceptions that can be raised within the block. For example, a CX_SY_ZERODIVIDE handler  224   a  and a cleanup handler  224   b  are defined. An overwrite-exit type modification will entirely replace the source code  222 . A pre-exit type modification can be incorporated at enhancement point  210 . A post-exit type modification can be incorporated at enhancement point  216 . In one implementation, a post-exit type modification can be invoked after a return from the method or function. 
     Any number of catch-exit type modifications for handling any number of exception types can be incorporated at enhancement point  212 . In one implementation, the exception can optionally be passed on to an enclosing function/method after being handled. A cleanup-exit type modification can be incorporated at enhancement point  214 . The exception can also be optionally passed to an enclosing function/method after being handled. Finally, post-exit enhancement types can be incorporated at enhancement point  216  or other points of normal function/method exit. Enhancement points other than those illustrated are possible. 
     The parameters of a source code component function can be optionally changed in accordance to TABLE 2. Fully typed tables parameters for ABAP functions are converted into changing parameters. Not fully typed table parameters are converted in changing parameters of the generic type table. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 IMPORTING 
                 EXPORTING 
                 CHANGING 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Overwrite-Exit 
                 Importing 
                 Exporting 
                 Changing 
               
               
                 Pre-Exit 
                 Importing 
                   
                 Changing 
               
               
                 Post-Exit 
                 Importing 
                 Changing 
                 Changing 
               
               
                 Post-Exit at Raise 
                 Importing 
                 Importing 
                 Importing 
               
               
                 Catch-Exit 
                 Importing 
                 Exporting 
                 Changing 
               
               
                   
               
            
           
         
       
     
       FIG. 3  illustrates execution of an enhanced method or function. The method/function is invoked (step  302 ). A method/function can be invoked any number of ways. For example, an invocation can be from a method, function, procedure, main program, event handler, or interrupt handler. If no pre-exit or overwrite-exit modification has been incorporated, the original source code for the function/method executes (step  308 ). If one or more pre-exit modifications have been incorporated, the one or more pre-exit modifications are executed before the original component (step  304 ). If one or more overwrite-exit modifications have been incorporated, the one or more overwrite-exit modifications are executed in lieu of the original component (step  306 ). During or after completion of execution of the original source code component, any post-exit, catch-exit or cleanup-exit modifications are executed (step  310 ). In one implementation, if a method or function has only importing or changing parameters, multiple overwrite-exit modifications are possible. In another implementation, when a method or a function has returning or exporting parameters, a special enhancement is automatically defined that combines the set of exporting and returning values to a single value. 
       FIG. 4  is a diagram of a source code component modification system  400 . Although a modification can be created by a process, an interactive enhancement tool  404  allows a user to create modifications for the source code component  402 . In one implementation, the enhancement tool  404  is part of an integrated development environment (IDE) that provides a graphical user interface (GUI) that allows a user to create modifications using context-sensitive editors. An example of an IDE is the ABAP Workbench, available from SAP AG. Other user interfaces are possible, including user interfaces other than graphical, such as user interfaces incorporating speech recognition. 
     The enhancement tool  404  presents the source code component  402  to the user and allows the user to interactively “modify” the component at enhancement points. However, the modifications are maintained separately  406  from the source code component  402 , even though it may appear to the user that the source code component  402  is being modified. In another alternative, the user interface  404  presents the source code component  402  (or a function/method declaration for the source code component) augmented with selectable GUI elements (e.g. buttons or hyperlinks) corresponding to enhancement points. By selecting such an element, the user is able to add one or more modifications for the chosen invocation point. 
     A component enhancer  412  incorporates an expression of the modifications  406  into a copy of the source code component  410  to create an enhanced component  414 . The component enhancer  412  expresses the modifications  406  in the same form or a different form in the copy  410 . The copy  410  of the source code component  402  is created by a duplicator component  408 . The copy can be a modified or translated version of the source code component  402 . For example, the copy  410  can be a byte code version of the source code component  402 . The enhanced component  414  is compiled/translated by compiler  416  to create an enhanced component  418 . By way of illustration, an enhanced component is source code, an intermediate language, machine independent or dependent code, instructions for a virtual or physical machine, or combinations of these. If the enhanced component  418  is not executable by itself, it can be compiled to create an executable compiled component. 
     A modification can itself be modified by the enhancement tool  404  to create modifications on top of modifications. For a example, a source code component is modified with a first modification mod 1 . A second modification mod 2  then modifies mod 1 , and so on. Each modification is applied in order beginning with the first to create an enhanced component. For example, the component enhancer  412  integrates the copy  410  and mod 1  to create a first enhanced component EC 1 . The enhanced component EC 1  can then be further enhanced by mod 2  to create a second enhanced component EC 2 , and so on. Alternatively, each modification mod 1  . . . modn can be merged into a single modification which can then be applied to the copy  410 . 
     If more than one modification is applicable to the same enhancement point, the modifications are incorporated into the copy  410  one after the other, in the order of creation, or in different order determined by information associated with modification. For example, a modification may be associated with a revision level so that revision modifications for earlier revisions are inserted ahead of later revisions. By way of a further example, a modification may be associated with a class of user (e.g., administrator, software developer, super user) where a class ordering determines the order of revisions. 
     By way of illustration, expressions of a pre-exit and post-exit modification are to be incorporated with source code component  402  which contains an ABAP class CL_TEST definition that defines a single method M 1 . In one implementation, the component enhancer incorporates into the copy  410  of CL_TEST (e.g., at enhancement point  208 ) a single local class  506  and one or more interfaces ( 502 ,  504 ) for each exit type modification in the modifications  406 . See  FIG. 5 . The interfaces contain method declarations for all exit modifications defined for the copy  410 . The user can add additional attributes and methods to the local class  506  but is not able to change the parameters or exceptions of the exit methods ( 510 ,  512 ) since the interfaces ( 502 ,  504 ) from which they depend are not editable. 
     The local class  508  has access to attributes and methods of the original class (CL_TEST) via a reference to the original class that is passed to the constructor  514  of the local class  508 . Alternatively, all interfaces ( 502 ,  504 ) are declared as friends of the original class (CL_TEST) to allow access to private and protected attributes and methods of the original class. The local class  508  is handled as a normal local class inside of an ABAP function group. All global variables of the function group can then be accessed. 
     In addition to creating the interfaces and local class at enhancement point  208 , the component enhancer  412  incorporates additional code into the copy  410  to cause invocation of the methods ( 510 ,  512 ) when the enhanced component  414  executes. For example, the following code is incorporated at enhancement point  208  for the pre-exit (where “&lt;enha_name&gt;”is the name of the enhancement): 
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Enhancement 2. 
               
            
           
           
               
               
            
               
                   
                 If lcl_&lt;enha_name&gt;=&gt;obj is initial. 
               
            
           
           
               
               
            
               
                   
                 create object lcl_&lt;enha_name&gt;=&gt;obj. 
               
               
                   
                 exporting original_class = me. 
               
            
           
           
               
               
            
               
                   
                 endif. 
               
               
                   
                 lcl_&lt;enha_name&gt;=&gt;obj -&gt;ipr_&lt;enha_name&gt;~m1( 
               
            
           
           
               
               
            
               
                   
                 Exporting 
               
               
                   
                 I1 = ... 
               
               
                   
                  Changing 
               
               
                   
                 C1 = .... ). 
               
            
           
           
               
               
            
               
                   
                 Endenhancement. 
               
               
                   
                   
               
            
           
         
       
     
     And the following code is incorporated at enhancement point  216  for the post-exit: 
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Enhancement 3. 
               
            
           
           
               
               
            
               
                   
                  If lcl_&lt;enha_name&gt;=&gt;obj is initial. 
               
            
           
           
               
               
            
               
                   
                 create object lcl_&lt;enha_name&gt;=&gt;obj 
               
            
           
           
               
               
            
               
                   
                 exporting original_class = me. 
               
            
           
           
               
               
            
               
                   
                  endif. 
               
               
                   
                  lcl_&lt;enha_name&gt;=&gt;obj-&gt;ipo_&lt;enha_name&gt;~m1( 
               
            
           
           
               
               
            
               
                   
                  Exporting 
               
            
           
           
               
               
            
               
                   
                  I1 = .... 
               
            
           
           
               
               
            
               
                   
                 Changing 
               
            
           
           
               
               
            
               
                   
                  C1 = ... 
               
               
                   
                  E1 = ... ). 
               
            
           
           
               
               
            
               
                   
                 Endenhancement. 
               
               
                   
                   
               
            
           
         
       
     
     Parameter modifications are incorporated into the copy  410  by the component enhancer  412 . Usually the new parameters are then used inside the method or function module by another enhancement technique (e.g., a pre/post exist, a source code plugin). For example, to add a new import parameter to a function module (e.g. an integer named NEW_PARM with default value  10 ). The following code can be added to a parameter enhancement point for a copy of the source code component: 
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 IMPORTING 
               
               
                   
                  Enhancement 1. 
               
            
           
           
               
               
            
               
                   
                 NEW_PARM TYPE I VALUE 10 
               
            
           
           
               
               
            
               
                   
                  Endenhancement. 
               
               
                   
                   
               
            
           
         
       
     
     The enhancement will be added by the component enhancer to a copy of the function. Methods (e.g., M 1  below) can similarly be enhanced, for example: 
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Class CL_TEST definition 
               
               
                   
                 public 
               
            
           
           
               
               
            
               
                   
                 create public . 
               
            
           
           
               
               
            
               
                   
                 public section. 
               
            
           
           
               
               
            
               
                   
                 Methods M1 
               
               
                   
                 importing 
               
            
           
           
               
               
            
               
                   
                 P1_ORIG type I . 
               
            
           
           
               
               
            
               
                   
                 Enhancement 1. 
               
            
           
           
               
               
            
               
                   
                 NEW_PARM TYPE I DEFAULT 10 
               
            
           
           
               
               
            
               
                   
                 Endenhancement. 
               
               
                   
                   
               
            
           
         
       
     
     In one implementation, enhancements consist of a source code part and a metadata part. The compiler combines a copy of the source code component and all enhancements into a compiled program (e.g., the complier searches for enhancements within the metadata.) Enhancements that are switched off globally are not considered at all. In one implementation, enhancements can be disabled statically (e.g., at compile time) or dynamically (e.g., at run time). Others that are switched on only for special circumstances or users, are compiled with surrounding ‘if’ statements. 
       FIG. 6  is a flow diagram  600  illustrating a method of enhancing a source code component. User input defining a first additional parameter to a first source code component and a first modification to the first source code component is obtained (step  602 ). The first modification to the first source code component can be dependent on the first additional parameter. The first source code component is not modified. A second source code component is produced by incorporating into the second source code component an expression of the first additional parameter and the first modification (step  604 ). A compiled program is created using the using the second source code component (step  606 ). 
     Source code is one or more (valid or invalid) statements or expressions in one or more programming languages or markup languages. Programming and markup languages can be defined by a grammar (e.g., generative, analytic, or ambiguous), e.g., without limitation, a context-free grammar (e.g., represented in Backus-Naur form), a regular grammar, a parsing expression grammar, or a link grammar. By way of illustration, a programming language can be procedural, functional, object-oriented, array-oriented, or a blend of two or more of these paradigms. Examples of programming languages include, without limitation, ABAP, Java® (available from Sun Microsystems, Inc. of Santa Clara, Calif.), JavaScript (also available from Sun Microsystems, Inc.), C++, C, Fortran, Perl, Lisp, Cobol, C#, J++, APL, APL 2 , A+, Glee, J, and K. A markup language can include without limitation any of the following: eXtensible Markup Language (XML), Hypertext Markup Language (HTML), Dynamic HTML (DHTML), and Extensible HTML (XHTML). Moreover, source code can also incorporate annotations, metadata and other information that is not part of a programming or markup language. For example, source code can include an XML Schema Definition (XSD) that describes the format of an XML document. 
     Embodiments of the invention and all of the functional operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed in this specification and structural equivalents thereof, or in combinations of them. Embodiments of the invention can be implemented as one or more computer program products, i.e., one or more computer programs tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program (also known as a program, software, software application, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file. A program can be stored in a portion of a file that holds other programs or data, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. 
     The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by, and apparatus can be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). 
     Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
     To provide for interaction with a user, embodiments of the invention can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. 
     Embodiments of the invention can be implemented in a computing system that includes a back-end component (e.g., a data server), a middleware component (e.g., an application server), or a front-end component (e.g., a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the invention), or any combination of such back-end, middleware, and front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet. 
     The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.