Abstract:
A method, computer program product, and computer system for creating a dynamic directory of objects. A request to modify a dynamic directory of a plurality of objects is received. Each of the plurality of objects is associated with one or more attribute-value pairs. One or more first object attribute-value pairs is determined for a first object. The dynamic directory is searched for the one or more first object attribute-value pairs. A first attribute-value pair is identified from the one or more first object attribute-value pairs. The first attribute-value pair is different than the one or more attribute-value pairs associated with the plurality of objects. The dynamic directory is modified based on the first attribute-value pair. Modifying the dynamic directory includes at least one of adding the first object to the dynamic directory, deleting the first object from the dynamic directory, and modifying an attribute-value pair of the first object.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to the field of internet of things (IoT) and, more particularly, to a dynamic directory of objects based on logical attributes. 
       BACKGROUND OF THE INVENTION 
       [0002]    The internet of things (IoT) is the network of physical objects or “things” embedded with electronics, software, sensors, and network connectivity to enable objects to collect and exchange data with one or more connected devices. The IoT allows objects to be sensed and controlled remotely across a network infrastructure. Each object is characterized by a one or more attributes, and is therefore uniquely identifiable. Identification and discovery of all objects facilitates open communication among objects. 
       SUMMARY 
       [0003]    According to one embodiment of the present disclosure, a method for creating a dynamic directory of objects is provided. The method includes receiving, by one or more processors, a request to modify a dynamic directory of a plurality of objects, wherein each of the plurality of objects is associated with one or more attribute-value pairs; determining, by one or more processors, one or more first object attribute-value pairs associated with a first object; searching, by one or more processors, the dynamic directory for the one or more first object attribute-value pairs; identifying, by one or more processors, a first attribute-value pair of the one or more first object attribute-value pairs, wherein the first attribute-value pair is different than the one or more attribute-value pairs associated with the plurality of objects; and modifying, by one more processors, the dynamic directory based on the first attribute-value pair, wherein modifying the dynamic directory comprises at least one of (i) adding the first object to the dynamic directory, (ii) deleting the first object from the dynamic directory, and (iii) modifying an attribute-value pair of the first object. 
         [0004]    According to another embodiment of the present disclosure, a computer program product for creating a dynamic directory of objects is provided. The computer program product comprises a computer readable storage medium and program instructions stored on the computer readable storage medium. The program instructions include program instructions to program instructions to receive a request to modify a dynamic directory of a plurality of objects, wherein each of the plurality of objects is associated with one or more attribute-value pairs; program instructions to determine one or more first object attribute-value pairs associated with a first object; program instructions to search the dynamic directory for the one or more first object attribute-value pairs; program instructions to identify a first attribute-value pair of the one or more first object attribute-value pairs, wherein the first attribute-value pair is different than the one or more attribute-value pairs associated with the plurality of objects; and program instructions to modify the dynamic directory based on the first attribute-value pair, wherein modifying the dynamic directory comprises at least one of (i) adding the first object to the dynamic directory, (ii) deleting the first object from the dynamic directory, and (iii) modifying an attribute-value pair of the first object. 
         [0005]    According to another embodiment of the present disclosure, a computer system for creating a dynamic directory of objects is provided. The computer system includes one or more computer processors, one or more computer readable storage media, and program instructions stored on the computer readable storage media for execution by at least one of the one or more processors. The program instructions include program instructions to program instructions to receive a request to modify a dynamic directory of a plurality of objects, wherein each of the plurality of objects is associated with one or more attribute-value pairs; program instructions to determine one or more first object attribute-value pairs associated with a first object; program instructions to search the dynamic directory for the one or more first object attribute-value pairs; program instructions to identify a first attribute-value pair of the one or more first object attribute-value pairs, wherein the first attribute-value pair is different than the one or more attribute-value pairs associated with the plurality of objects; and program instructions to modify the dynamic directory based on the first attribute-value pair, wherein modifying the dynamic directory comprises at least one of (i) adding the first object to the dynamic directory, (ii) deleting the first object from the dynamic directory, and (iii) modifying an attribute-value pair of the first object. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a functional block diagram of a computing environment, in accordance with an embodiment of the present disclosure; 
           [0007]      FIG. 2  illustrates a directed acyclic graph (DAG) of a single object in a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0008]      FIG. 3  illustrates superimposed DAGs of two objects in a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0009]      FIG. 4  depicts a directory organization for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0010]      FIG. 5  illustrates a hash map structure for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0011]      FIG. 6  illustrates a hash map structure for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0012]      FIG. 7  illustrates a hash map structure for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0013]      FIG. 8  illustrates a branch routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0014]      FIG. 9  illustrates a search routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0015]      FIG. 10  illustrates a deletion scheme for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0016]      FIG. 11  illustrates a high level insertion scheme for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0017]      FIG. 12  illustrates an insert routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
           [0018]      FIG. 13  is a block diagram of an exemplary environment of a computing device executing operations for a dynamic directory of objects based on logical attributes, in accordance with an embodiment of the present disclosure; and 
           [0019]      FIG. 14  is a block diagram of components of a computing device executing operations for a dynamic directory of objects based on logical attributes, in accordance with an embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Embodiments of the present invention recognize that identifying objects in the internet of things (IoT) is generally based on hardware specifications. Some methods of identifying objects in the IoT creates problems in dynamic settings where new objects are added or where one or more attributes associated with the objects change. Further recognized is that, generally devices can discover only those devices that are of a similar device technology. For example, a device utilizing Bluetooth® discovery techniques can only discover and identify other devices that are using Bluetooth® technology and within detection range of the first device. Embodiments of the present invention also recognize that similar challenges occur in service discovery architectures, wherein each standard for identifying objects has its own architecture for service discovery. Further recognized is that the IoT interconnects a number of heterogeneous objects. Consequently, there is a need for techniques that allow these heterogeneous objects to find each other in a uniform way. 
         [0021]    Embodiments further recognize that some protocols and structures for accessing and maintaining distributed directory information services, such as lightweight directory access protocol (LDAP), require defining a directory schema before deployment. Commonly, prior domain knowledge (e.g., types of objects, object functionality) is used, resulting in a static schema. Generally, adding objects or features of the objects within the directory involves modification to the directory structure and schema. Thus, adding objects and features is not an easily scalable process. 
         [0022]    Embodiments of the present invention provide for a dynamic directory of objects based on logical attributes. Embodiments of the present invention provide for creating a dynamic directory of heterogeneous objects based on attribute-value pairs associated with each of the objects. Embodiments of the present invention further provide for searching the directory for objects based on the attribute-value pairs. 
         [0023]    Embodiments of the present invention will now be described in detail with reference to the Figures.  FIG. 1  is a functional block diagram illustrating a computing environment, in accordance with an embodiment of the present invention. For example,  FIG. 1  is a functional block diagram illustrating computing environment  100 . Computing environment  100  includes device  110 A through device  110 N, and directory server  130 , all connected via network  120 . Device  110 A through device  110 N are sometimes collectively referred to as devices  110 . Devices  110  may include a greater or lesser number of devices than depicted in  FIG. 1 . Directory server  130  includes objects directory manager  132 , objects directory  134 , and objects database  136 . 
         [0024]    In various embodiments, directory server  130  is a computing device that can be a standalone device, a server, a laptop computer, a tablet computer, a netbook computer, a personal computer (PC), or a desktop computer. In another embodiment, directory server  130  represents a computing system utilizing clustered computers and components to act as a single pool of seamless resources. In general, directory server  130  can be any computing device or a combination of devices with access to devices  110 , and with access to and/or capable of executing some or all of objects directory manager  132 , objects directory  134 , and objects database  136 . Directory server  130  may include internal and external hardware components, as depicted and described in further detail with respect to  FIG. 4 . 
         [0025]    In this exemplary embodiment, objects directory manager  132 , objects directory  134 , and objects database  136  are stored on directory server  130 . In other embodiments, some or all of objects directory manager  132 , objects directory  134 , and objects database  136  may reside on another computing device, provided that each can access and is accessible by each other of objects directory manager  132 , objects directory  134 , objects database  136  and devices  110 . In yet other embodiments, some or all of objects directory manager  132 , objects directory  134 , and objects database  136  may be stored externally and accessed through a communication network, such as network  120 . Network  120  can be, for example, a local area network (LAN), a wide area network (WAN) such as the Internet, or a combination of the two, and may include wired, wireless, fiber optic or any other connection known in the art. In general, network  120  can be any combination of connections and protocols that will support communications between directory server  130  and devices  110 , in accordance with a desired embodiment of the present invention. 
         [0026]    Objects directory manager  132  operates to manage objects within computing environment  100 . In some embodiments, objects directory manager  132  searches for and identifies new objects in computing environment  100 . In some embodiments, objects directory manager  132  classifies the objects into a class and a subclass, creating an applicable DAG (Directed Acyclic Graph) of the objects under the subclass. In some embodiments, objects directory manager  132  updates metadata of the objects. In other embodiments, objects directory manager  132  adds or deletes objects from objects directory  134 . Objects directory manager  132  classifies an new object into a class and a subclass by comparing the attributes of the new object with the attributes of objects already in each of the class and the subclass. Objects directory manager  132  further organizes the objects in the subclass into a tree structure, specifically a DAG, based on the attribute-value pairs of the objects. 
         [0027]    Objects directory manager  132  superimposes complex DAG structures to enable high-speed searching of objects. In some embodiments, an ontology-based implementation is used when relationships among objects are also specified and inferences need to be drawn. 
         [0028]    Objects directory  134  is a directory that includes objects identified and classified by objects directory manager  132 . In some embodiments, objects within objects directory  134  are associated with a class, a subclass, and various attribute-value pairs. In some embodiments, each object in objects directory  134  is arranged in an object classification layer (OCL). Each OCL includes one or more classes and one or more subclasses. Classification of objects into classes and subclasses is used to provide a fast lookup search of objects in a scalable environment of IoT. The one or more attribute-value pairs associated with an object may be viewed as a DAG. 
         [0029]    Objects database  136  is a data repository that may be written to and read by objects directory manager  132  and objects directory  134 . Object data, such as OCL and DAG classifications, may be stored to objects database  136 . In some embodiments, objects database  136  may be written to and read by devices  110  or by programs and entities outside of computing environment  100  in order to populate the repository with object data. Object data includes information that describes objects (e.g., class, subclass, attribute, attribute values, etc.). 
         [0030]    In various embodiments of the present invention, devices  110  are a computing device that can be a standalone device, a server, a laptop computer, a tablet computer, a netbook computer, a personal computer (PC), a desktop computer, a personal digital assistant (PDA), a smart phone, sensor, wearable devices, or any programmable electronic device capable of communicating with directory server  130  via network  120 . In another embodiment, devices  110  represents a computing system utilizing clustered computers and components to act as a single pool of seamless resources. In general, devices  110  can be any computing device or a combination of devices with access to directory server  130 , and with access to and/or capable of executing some or all of objects directory manager  132 , objects directory  134 , and objects database  136 . In some embodiments, devices  110  includes a user interface (UI) by which a user provides user input to devices  110 . Devices  110  can communicate such user input, via network  120 , to directory server  130 . Devices  110  may include internal and external hardware components, as depicted and described in further detail with respect to  FIG. 14 . 
         [0031]      FIG. 2  illustrates a DAG of a single object for dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0032]    In one embodiment, a characteristic set of an object can be viewed as an object DAG with attributes and values, where the values are associated with the attributes. In another embodiment, a characteristic set is represented as a tree structure. In an example DAG depicted in  FIG. 2 , there are “n” attribute-value pairs, identified as attribute 1-value 1 (elements  202  and  204  respectively), attribute 2-value 2 (elements  206  and  208  respectively) through attribute n-value n (elements  210  and  212  respectively), in a characteristic set of object D1 (element  214 ). Attribute 1 (element  202 ) is associated with value 1 (element  204 ), attribute 2 (element  206 ) is associated with value 2 (element  208 ), and so on, with attribute n (element  210 ) having an association with value n (element  212 ). In one embodiment, attribute-value pairs are not ordered based on any weighting factors of attributes. As represented in  FIG. 2 , object D1 (element  214 ) is associated with all attribute-value pairs within the DAG. 
         [0033]      FIG. 3  illustrates superimposed DAGs for two objects in a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0034]    In one embodiment, a graph of all objects in a subclass is a superimposition of the DAG of each of the objects in the subclass. In one example, a group of objects includes only two objects, D1 (element  214 ) and D2 (element  306 ). A graph of the group can be created by superimposing the DAG of object D1 (element  214 ) and the DAG of object D2 (element  306 ), as depicted in  FIG. 3 . In this example, Value 1 (element  204 ) is associated with two attributes, Attribute 2 (element  206 ) and Attribute 3 (element  302 ). Attribute 2 (element  206 ) is associated with object D1 (element  214 ), and Attribute 3 (element  302 ) is associated with object D2 (element  306 ). Object D1 (element  214 ) is associated with N attribute-value pairs (see  FIG. 2  description). Object D2 (element  306 ) is associated with two attribute-value pairs, Attribute 1-Value 1 (elements  202  and  204  respectively) and Attribute 3-Value 3 (elements  302  and  304  respectively). In some embodiments, an attribute-value pair is associated with only one device. In some embodiments, an attribute-value pair is associated with multiple devices. In a subclass consisting of a large number of objects, such a superimposition will result in a very complex graph or tree-like structure. 
         [0035]      FIG. 4  depicts a directory organization for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure.  FIG. 4  depicts dynamic directory  400 . 
         [0036]    In one embodiment, in order to overcome the complexity of tree structures and facilitate fast searches, objects in a directory are classified, using clustering, into one or more high-level classes, based on the attributes of the objects. Each class is further organized into one or more subclasses, based on attributes of the objects. The resulting organization of objects into classes and subclasses is carried out into an objects classification layer (OCL). Each class may include a different number of subclasses. The number of classes and the number of subclasses within a class depends upon the algorithm used in an OCL. 
         [0037]      FIG. 4  depicts a directory with N number of classes, depicted as class 1 (element  401 ) through class N (element  403 ).  FIG. 4  illustrates an example of class 2 (element  402 ) being further organized into M subclasses, labeled as subclass 2.1 (element  404 ), subclass 2.2 (element  405 ), through subclass 2.M (element  406 ). Each object within each subclass is further organized into a DAG, based on the attribute-value pairs associated with each of the objects, as discussed in  FIG. 2 . In one embodiment, a subclass is associated with two or more attribute nodes. 
         [0038]    In this example,  FIG. 4  illustrates a superimposition of DAGs of eight objects in subclass 2.2 (element  405 ). Attribute  407 , an attribute node of subclass 2.2 (element  405 ), is associated with five values, the first of which is value  408 . The attribute-value pair depicted by Attribute  407 -value  408  is associated with four objects: object  413 , object  414 , object  415 , and object  418 , each of which is associated with one other attribute-value pair. Object  413  is associated with attribute  409 -value  410 . Object  414  is associated with attribute  409 -value  411 . Object  415  is associated with attribute  409 -value  412 . Object  418  is associated with attribute  416 -value  417 . In one embodiment, objects in a subclass are organized into a tree structure, wherein the root node of the subclass corresponds to the subclass. 
         [0039]    In some embodiments, dynamic directory  400  is used by objects directory manager  132  to manage objects identified in within dynamic directory  400 . In some embodiments, objects directory manager  132  manages objects based on a categorization of one or more objects. The categorization can be a class, subclass, attribute, or value. For example, objects directory manager  132  can manage all objects that are categorized under attribute  409 . In this example, any action chosen for objects categorized under attribute  409  will affect object  413 , object  414 , and object  415 . In another example, objects directory manager  132  can manage objects categorized under value  410 . In this example, only object  413  will be affected by actions chosen for value  410 . Dynamic directory  400  allows objects directory manager  132  to manage as few or as many objects at one time, based on attribute-value categorization. 
         [0040]      FIG. 5  illustrates a hash map structure for dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0041]    A hash map, sometimes referred to as a hash table, is a data structure that is used to implement an associative array, a structure that maps one or more keys to a unique value. Hash maps are used in computer software for rapid data lookup. Hash maps use a hash function to accelerate table or database lookup by detecting duplicated records in a large file. Although different hash functions exist, and can be implemented, an embodiment of the present invention implements a JSW hash function. 
         [0042]    In one embodiment, information about classes and subclasses in a directory are maintained above the cluster hierarchy as illustrated in  FIG. 5 . Hash map  502  includes a quantity of X attributes, each of which is a key that maps to a linear list of classes and subclasses, wherein a class and a subclass are as previously described. For example, attribute 1 (element  504 ) is a key that maps to a linear list of N classes, from class 1 (element  506 ) through class N (element  508 ). Each of the N classes is associated with zero or more subclasses. For example, class 1 (element  506 ) is associated with M subclasses, from subclass 1 (element  510 ) to subclass M (element  512 ). 
         [0043]      FIG. 6  illustrates a hash map structure for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0044]    In one embodiment, a second hash map structure is maintained for each subclass. In  FIG. 6 , hash map  602  includes a quantity of X attributes, and maps from attribute to DeviceInfoStruct. The DeviceInfoStruct includes N entries wherein each entry contains a value of the hashed attributes and the list of objects (or a pointer to objects data or meta data) possessing the value of the hashed attribute. For example, attribute 2 (element  604 ), points to value 2.1 (element  606 ). In some embodiments, value 2.1 (element  606 ) includes a list of devices having the characterization of value 2.1. DeviceInfoStruct also has a hash map (element  608 ) of M entries, each maps a value to DeviceInfoStruct. The result of this structure is nested multiple DeviceInfoStructs for a hashed attribute. For example, hash 1 (element  609 ) includes nested DeviceInfoStruct A (element  610 ). This is done to support a large value set of attributes that characterize objects. In some embodiments, a linear search for an attribute value-pair can be expensive. 
         [0045]      FIG. 7  illustrates a hash map structure for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0046]    To reduce a potentially expensive linear search for values of an attribute, the value array of N entries as in the example illustrated in  FIG. 6  may be performed as illustrated in  FIG. 7 . The search is defined by two parts, HashPart which has a number of entries defined by the variable q, and LinearPart which is defined by a variable of n. For entries[1 . . . n], a first segment of values will be called HashPart[1, . . . , q], and the remaining values will be called LinearPart[q+1, . . . , n]. The first q entries are accessed by using a value as a key to a hash function to obtain a hash value of H, and then using the corresponding hash function to access a skip-list beginning from HashPart[H] extending into a LinearPart[L] as shown in  FIG. 7 . Every entry in the LinearPart contains a pointer to a subsequent entry (e.g., LinearPart[M]). This is done because a single hash value H may be obtained for multiple values of an attribute. An experiment with n=32 and m=256 and a depth=4 has resulted in storage of nearly one million entries corresponding to values of an attribute, assuming that a good hashing is chosen, leading to a nearly uniform distribution, leading to a look up of only four such DeviceInfoStructs. This would help in overcoming the near linear search behavior of hashes asymptotically. 
         [0047]      FIG. 8  illustrates a branch routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0048]    The format of the branch routine, as depicted in  FIG. 8 , is BRANCH(value, depth). In one embodiment, a branch routine as depicted in  FIG. 8  is called by DeviceInfoStruct at location depth to determine the child DeviceInfoStruct at location depth+1. In one embodiment, the root DeviceInfoStruct is at depth 0. In order to branch from an (i−1) th  level to an i th  level, the character i positions from the right is used as an input to a hash function to obtain the hash_value. The hash_value returned is used to refer the child DeviceInfoStruct to branch to the location that is stored in hash table in DeviceInfoStruct. 
         [0049]      FIG. 9  illustrates a search routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0050]    The format of the search function, as depicted in  FIG. 9 , is SEARCH(root, value, depth), where root is DeviceInfoStruct at a depth from where the search will be conducted. To conduct a search from the root of the DeviceInfoStruct tree, a search string is called using a depth of 0, as in SEARCH(root, value, 0). SEARCH( ) begins to look for the value in the skip-list corresponding to the hash value h, from HashPart[H]. If at a node, the value in the skip-list matches the value that is stored in that node, then that node is returned. If a node is not found in the skip-list, then a determination is made as to whether there are one or more characters remaining in the value to branch further. If there are one or more characters remaining, the SEARCH( ) routine is executed recursively, otherwise, the search routine returns a null value. This SEARCH routine is a basic search routine. To search for an object, for each of the specified attributes, first the class and the subclass are ascertained. Next, within the subclass, the SEARCH( ) routine is called. The response to the search is the intersection of all such SEARCH ( ) routines of all specified attributes. 
         [0051]      FIG. 10  illustrates a deletion routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0052]    The format of the deletion routine is DELETION_SCHEME(root,value,deviceID), as depicted in  FIG. 10 . In line 1, SEARCH(root, value, 0) routine is executed to search for a node that contains the input value. If the search function identifies a node that contains the input value, then the deviceID is removed from the DeviceList of the node. If the search function does not identify a node that contains the input value, then no changes are made. 
         [0053]    If a node is found, the routine then determines whether the node is the last node in a skip-list and the DeviceList of the node is empty. If those two conditions are met, then the node is labeled “Not Occupied” and the skip-list is truncated by 1 node. If the node that is found is not the last node in the skip-list, yet the DeviceList is empty, then the node is labeled “Empty” to preserve the skip-list. 
         [0054]      FIG. 11  illustrates a high level insertion scheme for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0055]    The format of the high level insertion scheme, as depicted in  FIG. 11 , is INSERTION_SCHEME(root,value,deviceID), in which root is the root of the DeviceInfoStruct tree. This routine operates to first determine whether a value for the input deviceID already exists in the DeviceInfoStruct tree, and if not, insert the value into the DeviceInfoStruct tree. 
         [0056]    The first step is to call the routine SEARCH(root,value,0) to determine whether there is an entry in the DeviceInfoStruct tree having the corresponding value. If no such entry exists then INSERT(root,value,deviceID,0) is executed. If an entry in the DeviceInfoStruct tree does have the corresponding value, then deviceID is added to the DeviceList of the node, and the node, if labeled anything other than “Occupied”, is labeled “Occupied”. 
         [0057]      FIG. 12  illustrates an insert routine for a dynamic directory of objects based on logical attributes, on a computing device within the computing environment of  FIG. 1 , in accordance with an embodiment of the present disclosure. 
         [0058]    The format of the insert routine, as depicted in  FIG. 12 , is INSERT(root,value,deviceID,depth), in which root is the root of the DeviceInfoStruct tree. This routine operates to search for an entry in which to insert a value for deviceID, by branching to a depth equal to the length of an entry (i.e., number of characters in the string). If no entry is found that meets this condition, the routine searches for an entry that has a value length greater than the length of the input value. If the routine identifies an entry with a value length that is greater than the length of the input value, the entry is updated with the input value and the input deviceID. The INSERT( ) routine is repeated to find an entry for the replaced value and the associated DeviceList at greater depths as it still has characters left to branch. If no such replaceable entry is found then value is inserted into an entry in the Over Flow List of the last DeviceInfoStruct reached at the depth equal to length of value. 
         [0059]    A node or an entry may have one of the following three status values:
       1. Not Occupied—Initially, all nodes are labeled “Not Occupied”.   2. “Occupied”—Responsive to a value being placed in an entry, the entry is marked with “Occupied”.   3. “Empty”—This status implies that an entry is still part of a skip-list, even though the entry does not contain a value. This status is assigned responsive to the deviceList of a value becoming empty during deletion and the corresponding entry is available for inserting new values with the same hash value. If an Empty status is not assigned in this manner, there is a risk of corrupting the skip-list.       
 
         [0063]    In lines 1 through 3, flag is assigned 0 if branching to a depth equal to the length of value is completed and no further branching is possible from the current DeviceInfoStruct. Flag is assigned 1 if further branching is possible. 
         [0064]    In lines 6 through 14, the routine makes determinations regarding the skip-list. In lines 7 through 9, if a first entry marked Empty is identified, then value and the corresponding deviceID are entered into the first entry. In line 10, the last node in the skip-list is assigned the variable last. In lines 11 through 13, if the depth is greater than or equal to the length of value, then the program searches for an entry in the skip-list wherein the length of value in the entry is greater than the input value length. In lines 15 through 20, the program searches for an entry marked “Not Occupied” in LinearPart[ ] and, if such an entry is found, the program inserts the value and deviceID into the entry, and links the entry with the last of the skip-list. 
         [0065]    In lines 21 through 23, the program determines whether depth is less than the length of value, and if so, a branch is executed recursively, by calling the INSERT( ) routine, replacing depth with depth+1. 
         [0066]    In lines 24 through 29, if an entry of rep_node was identified with a length of value stored greater than the input value, then value is stored at rep_node and the program recursively calls INSERT( ) with the old value in rep_node. 
         [0067]    In line 30, the program stores value in an entry in the current DeviceInfoStruct&#39;s Over Flow List, OFL[ ]. 
         [0068]      FIG. 13  is a block diagram of system components of a computing device executing operations for a dynamic directory of objects based on logical attributes, in accordance with an embodiment of the present disclosure. 
         [0069]      FIG. 13  depicts an exemplary environment  900 , in which IoT object  910  communicate with attribute-value pair based directory system (AVPBDS)  920  via request and command pairs  902 A and  902 B through  908 A and  908 B. 
         [0070]    IoT object  910  represents one or more heterogeneous devices in the IoT, such as device  110 A. For purposes of explanation of  FIG. 13 , IoT object  910  will be referred to as a single device; however, IoT object  910  can include multiple devices. 
         [0071]    AVPBDS  920  is a directory system that operates to receive input from IoT object  910 , process the input, and send a response to IoT object  910 . In one embodiment, AVPBDS  920  is an example of directory server  130 . AVPBDS  920  includes OCL  922 , destroyer module  923 , objects directory  924 , search module  925 , objects database  926 , and updater module  927 . In some embodiments, OCL  922 , destroyer module  923 , search module  925 , and updater module  927  together are an example of objects directory manager  132 . In some embodiments, objects directory  924  is an example of objects directory  134 . In some embodiments, objects database  926  is an example of objects database  136 . 
         [0072]    In some embodiments, environment  900  is used to register an object. For example, IoT object  910  sends request  902 A to AVPBDS  920  and receives response  902 B from AVPBDS  920 . For example, request  902 A is sent to AVPBDS  920  from a mobile device that is new to environment  900 , requesting that the mobile device be registered in environment  900 . The request includes characteristic data (i.e., attribute-value pairs) about the mobile device. AVPBDS  920  receives the request, organizes and classifies the mobile device into the OCL (i.e., classes and subclasses) based on the characteristic data included in the request. AVPBDS  920  creates entries in the objects directory and objects database which, in some embodiments, includes the classification of IoT object  910 . AVPBDS  920  sends a confirmation response (e.g., response  902 B) to the mobile device, confirming that the mobile device is registered. 
         [0073]    In some embodiments, environment  900  is used to de-reregister an object. For example, IoT object  910  sends request  904 A to AVPBDS  920  and receives response  904 B from AVPBDS  920 . For example, request  904 A is sent from a mobile device that is being removed from environment  900  (e.g., taken out of service) to AVPBDS  920 , requesting that the mobile device be deregistered from environment  900 . AVPBDS  920  receives the request, processes the request, utilizing destroyer module  923  to delete information about the mobile device from objects directory  924  and objects database  926 , and sends a confirmation response (e.g., response  904 B) to the mobile device, confirming that the mobile device has been deregistered. 
         [0074]    In some embodiments, environment  900  is used to find and manage objects. For example, IoT object  910  sends request  906 A to AVPBDS  920  and receives response  906 B from AVPBDS  920 . For example, request  906 A is sent from a mobile device to AVPBDS  920 , requesting that a search be conducted to identify all wireless devices within environment  900 . AVPBDS  920  receives the request, processes the request, utilizing search module  925  to conduct a search of objects directory  924  and objects database  926 , and sends response  906 B, with results of the search, to the mobile device. 
         [0075]    In some embodiments, environment  900  is used to update object information. For example, IoT object  910  sends request  908 A to AVPBDS  920  and receives response  908 B from AVPBDS  920 . For example, request  908 A is sent from a mobile device to AVPBDS  920 , requesting an update be made to information in AVPBDS  920  regarding attribute-value pairs of the mobile device. In one example, the update request may indicate that a new version of firmware is resident on the mobile device. AVPBDS  920  receives the request, utilizes updater module  927  to update (i.e., modify) information about the mobile device in objects directory  924  and objects database  926 , and sends a confirmation response (e.g., response  908 B) to the mobile device to confirm that updates have been completed. 
         [0076]      FIG. 14  is a block diagram of components of a computing device, generally designated  1000 , in accordance with an embodiment of the present disclosure. In one embodiment, computing system  1000  is representative of directory server  130 . For example,  FIG. 14  is a block diagram of directory server  130  within computing environment  100  executing operations of objects directory manager  132 . 
         [0077]    It should be appreciated that  FIG. 14  provides only an illustration of one implementation and does not imply any limitations with regard to the environments in which different embodiments may be implemented. Many modifications to the depicted environment may be made. 
         [0078]    Computing system  1000  includes processor(s)  1002 , cache  1006 , memory  1004 , persistent storage  1010 , input/output (I/O) interface(s)  1012 , communications unit  1014 , and communications fabric  1008 . Communications fabric  1008  provides communications between cache  1006 , memory  1004 , persistent storage  1010 , communications unit  1014 , and input/output (I/O) interface(s)  1012 . Communications fabric  1008  can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric  1008  can be implemented with one or more buses or a crossbar switch. 
         [0079]    Memory  1004  and persistent storage  1010  are computer readable storage media. In this embodiment, memory  1004  includes random access memory (RAM). In general, memory  1004  can include any suitable volatile or non-volatile computer readable storage media. Cache  1006  is a fast memory that enhances the performance of processor(s)  1002  by holding recently accessed data, and data near recently accessed data, from memory  1004 . 
         [0080]    Program instructions and data used to practice embodiments of the present invention may be stored in persistent storage  1010  and in memory  1004  for execution by one or more of the respective processor(s)  1002  via cache  1006 . In an embodiment, persistent storage  1010  includes a magnetic hard disk drive. Alternatively, or in addition to a magnetic hard disk drive, persistent storage  1010  can include a solid state hard drive, a semiconductor storage device, read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, or any other computer readable storage media that is capable of storing program instructions or digital information. 
         [0081]    The media used by persistent storage  1010  may also be removable. For example, a removable hard drive may be used for persistent storage  1010 . Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage  1010 . 
         [0082]    Communications unit  1014 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  1014  includes one or more network interface cards. Communications unit  1014  may provide communications through the use of either or both physical and wireless communications links. Program instructions and data used to practice embodiments of the present invention may be downloaded to persistent storage  1010  through communications unit  1014 . 
         [0083]    I/O interface(s)  1012  allows for input and output of data with other devices that may be connected to each computer system. For example, I/O interface(s)  1012  may provide a connection to external device(s)  1016  such as a keyboard, keypad, a touch screen, and/or some other suitable input device. External device(s)  1016  can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. Software and data used to practice embodiments of the present invention can be stored on such portable computer readable storage media and can be loaded onto persistent storage  1010  via I/O interface(s)  1012 . I/O interface(s)  1012  also connect to display  1018 . 
         [0084]    Display  1018  provides a mechanism to display or present data to a user and may be, for example, a computer monitor. 
         [0085]    The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
         [0086]    The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
         [0087]    Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
         [0088]    Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
         [0089]    Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
         [0090]    These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0091]    The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0092]    The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
         [0093]    The term(s) “Smalltalk” and the like may be subject to trademark rights in various jurisdictions throughout the world and are used here only in reference to the products or services properly denominated by the marks to the extent that such trademark rights may exist. 
         [0094]    The term “exemplary” means of or relating to an example and should not be construed to indicate that any particular embodiment is preferred relative to any other embodiment. 
         [0095]    The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.