System and method for importing and exporting data between an object oriented computing environment and an external computing environment

Claims

That which is claimed:

1. A system for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said data importing and exporting system comprising:

datalist generating means for generating datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported and exported between external computing environment and the object oriented computing environment;

metadata generating means for generating a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters;

importing means, responsive to a request from said external computing environment to import external data into said object oriented computing environment, for identifying an object oriented computing environment attribute from said datalist objects and for identifying a corresponding metadata object, and for applying the alternate conversion parameters in said corresponding metadata object to said external data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data and place said object oriented data into a corresponding data object which is associated with said corresponding metadata object; and

exporting means, responsive to a request from said object oriented computing environment to export object oriented data from an object in said object oriented computing environment to said external computing environment, for identifying a metadata object corresponding to said object and for identifying said external data name corresponding to said metadata object from said datalist, and for applying the alternate conversion parameters in the corresponding metadata object to said object oriented data from said object if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert object oriented data into external data.

2. The system of claim 1 further comprising:

an external object class including external object class methods for importing data, exporting data, and finding objects; and

means for causing each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, to inherit from said external object class, to thereby inherit said external object class methods.

3. The system of claim 1 further comprising means for adding tags to each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes.

4. The system of claim 1 wherein said exporting means further comprises means for placing said external data into an output data file.

5. A system for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said data importing and exporting system comprising:

means for identifying each object in said object oriented computing environment from which data is exported and into which data is imported;

metadata generating means for generating a metadata object for each identified object, said metadata object including conversion parameters for converting attributes of each identified object into a corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters;

importing means, responsive to a request from said external computing environment to import external data into said object oriented computing environment, for identifying a corresponding metadata object, and for applying the alternate conversion parameters in said corresponding metadata object to said external data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data and place said object oriented data into a corresponding data object which is associated with said corresponding metadata object; and

exporting means, responsive to a request from said object oriented computing environment to export object oriented data from an object in said object oriented computing environment to said external computing environment, for identifying a metadata object corresponding to said object and for applying the alternate conversion parameters in the corresponding metadata object to said object oriented data if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert said object oriented data into external data.

6. The system of claim 5 further comprising:

an external object class including external object class methods for importing data, exporting data, and finding objects; and

means for causing each identified object to inherit from said external object class, to thereby inherit said external object class methods.

7. The system of claim 5 further comprising means for adding tags to each identified object.

8. The system of claim 5 wherein said exporting means further comprises means for placing said external data into an output data file.

9. A system for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said object oriented computing environment including datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported and exported between the external computing environment and the object oriented computing environment, said object oriented computing environment further including a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters, said data importing and exporting means comprising:

importing means, responsive to a request from said external computing environment to import external data into said object oriented computing environment, for identifying an object oriented computing environment attribute from said datalist objects and for identifying a corresponding metadata object, and for applying the alternate conversion parameters in said corresponding metadata object to said external data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data and place said object oriented data into a corresponding data object which is associated with said corresponding metadata object; and

exporting means, responsive to a request from said object oriented computing environment to export object oriented data from an object in said object oriented computing environment to said external computing environment, for identifying a metadata object corresponding to said object and for identifying said external data name corresponding to said metadata object from said datalist, and for applying the alternate conversion parameters in the corresponding metadata object to said object oriented data from said object if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert said object oriented data into external data.

10. The system of claim 9 further comprising:

an external object class including external object class methods for importing data, exporting data, and finding objects; and

means for causing each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, to inherit from said external object class, to thereby inherit said external object class methods.

11. The system of claim 9 further comprising means for adding tags to each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes.

12. The system of claim 9 wherein said exporting means further comprises means for placing said external data into an output data file.

13. A method for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said date importing and exporting method comprising the steps of:

generating a datalist which lists an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported and exported between the external computing environment and the object oriented computing environment;

generating a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters;

identifying an object oriented computing environment attribute from said datalist in response to a request from said external computing environment to import said data line said object oriented computing environment:

identifying a corresponding metadata object;

applying the alternate conversion parameters in said corresponding metadata object to said data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data; and

placing said object oriented data into a corresponding data object which is associated with said corresponding metadata object.

14. The method of claim 13 further comprising the step of:

generating an external object class including external object class methods for importing data, exporting data, and finding objects; and

causing each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, to inherit from said external object class, to thereby inherit said external object class methods.

15. The method of claim 13 further comprising the step of adding tags to each said object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes.

16. The method of claim 13 further comprising the steps of:

identifying an object oriented computing environment attribute from said datalist in response to a request from said external computing environment to import said data into said object oriented computing environment;

identifying a corresponding metadata object;

applying the alternate conversion parameters in said corresponding metadata object to said data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data; and

placing said object oriented data into a corresponding data object which is associated with said corresponding metadata object.

17. A method for importing and exporting data between an external computing environment operating on one or more computer platforms and an object oriented computing environment operating on one or more computing platforms, said data importing and exporting method comprising the steps of:

generating a datalist which lists an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported and exported between the external computing environment and the object oriented computing environment;

generating a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters;

identifying a metadata object corresponding to said object in response to a request from said object oriented computing environment to export data from an object in said object oriented computing environment to said external computing environment;

identifying said external data name corresponding to said metadata object from said datalist;

applying the alternate conversion parameters in the corresponding metadata object to said data from said object if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert object oriented data into external data.

18. The method of claim 17 further comprising the step of placing said external data into an output data file.

19. A method for importing data from an external computing environment operating on one or more computer platforms to an object oriented computing environment operating on one or more computing platforms, said object oriented computing environment including datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is imported to the object oriented computing environment, said object oriented computing environment further including a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters, said data importing method comprising the steps of:

identifying an object oriented computing environment attribute from said datalist objects in response to a request from said external computing environment to import said data into said object oriented computing environment;

identifying a corresponding metadata object;

applying the alternate conversion parameters in said corresponding metadata object to said external data if included in said corresponding metadata object, and for applying the default conversion parameters in said corresponding metadata object to said external data in the absence of said alternate conversion parameters in said metadata object, to thereby convert said external data into object oriented data; and

placing said object oriented data into a corresponding data object which is associated with said corresponding metadata object.

20. A method for exporting data from an object oriented computing environment operating on one or more computing platforms to an external computing environment operating on one or more computer platforms, said object oriented computing environment including datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment attribute and a corresponding external data format for each external data field in the external computing environment which is exported from the object oriented computing environment, said object oriented computing environment further including a metadata object for each object in said object oriented computing environment which includes one of said corresponding object oriented computing environment attributes, said metadata object including conversion parameters for converting the corresponding object oriented computing environment attribute into said corresponding external data format, said conversion parameters including at least one of default conversion parameters and alternate conversion parameters, said data exporting method comprising the steps of:

identifying a metadata object corresponding to an object in response to a request from said object oriented computing environment to export data from the object in said object oriented computing environment to said external computing environment;

identifying said external data name corresponding to said metadata object from said datalist; and

applying the alternate conversion parameters in the corresponding metadata object to said data from said object if included in said corresponding metadata object, and for applying the default conversion parameters in the corresponding metadata object to said object oriented data from said object in the absence of said alternate conversion parameters in said metadata object, to thereby convert object oriented data into external data.

FIELD OF THE INVENTION

This invention relates to data processing systems and methods and more particularly to object oriented computing environments.

BACKGROUND OF THE INVENTION

Object oriented programming systems and processes, also referred to as "object oriented computing environments", have been the subject of much investigation and interest in state of the art data processing environments. As is well known to those having skill in the art, object oriented computing environments are composed of a large number of "objects". An object is a data structure, also referred to as a "frame", and a set of operations or functions, also referred to as "methods", that can access that data structure. The frame has many "slots", each of which contains an "attribute" of the data in the slot. The attribute may be a primitive (such as an integer or string) or an object reference which is a pointer to another object.

Each defined object will usually be manifested in a number of "instances". Each instance contains the particular data structure for a particular example of the object. In An object oriented computing environment, data is processed by requesting an object to perform one of its methods by sending the object a "message". The receiving object responds to the message by choosing the method that implements the message name, executing this method on the named instance, and returning control to the calling high level routine along with the results of the method.

As object oriented computing environments proliferate, it becomes increasingly important to allow import and export of data between the object oriented computing environment and an external computing environment. The external computing environment may be a conventional functionally programmed computing environment or may be another object oriented computing environment. Typical interfaces between an object oriented environment and an external environment may include an interactive host user interface, a batch interface, a remote work station user interface, or other well known interfaces between computing environments.

In importing and exporting data between an object oriented computing environment and an external computing environment, an interface is typically defined and generated between the object oriented computing environment and the external computing environment. The interface will contain mechanisms for validating the imported and exported data, and for converting the imported and exported data to a form which is usable by the importing or exporting system. As the number of interfaces proliferate, the data importing and exporting mechanisms must be duplicated and customized for each type of interface. The need to generate and maintain a separate user interface adds to program complexity and cost and increases the possibility of errors.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an improved object oriented computing environment.

It is another object of the invention to provide an object oriented computing environment including a system and method for exporting and importing data to and from other computing environments.

It is yet another object of the present invention to provide a common external interface to objects within an object oriented environment.

These and other objects are provided, according to the present invention, by encapsulating the validation, conversion and update control mechanisms for objects in "metadata" about the objects. This encapsulation allows metadata logic to operate identically on a variety of internal objects, freeing the object oriented computing environment from the need to duplicate the same control logic for each user interface. By using a tagging scheme, which modifies the attributes of an object to define the conversion and validation parameters for importing and exporting data, the form and context in which data is imported and exported can be generally defined. Separate interfaces for communicating between the object oriented computing environment and each external computing environment are therefore not required. Logic to convert and validate input to an object is needed only when special conversion techniques or validations are required for an imported attribute.

In particular, a system for importing and exporting data between an external computing environment and an object oriented computing environment includes datalist generating means which operates during program generation (build time), to generate datalist objects which list an external computing environment data field name, a corresponding object oriented computing environment internal attribute name, and a corresponding external data format for each external data field in the external computing environment which is imported and exported between the object oriented computing environment and the external computing environment. An external object class is defined, including conversion parameters for converting the corresponding object oriented computing environment attribute into the corresponding external data format. The external object class frames, referred to as "metadata", contain the object oriented computing environment attributes which are used for import and export. Metadata generating means is also provided, for generating, at program generation time, a metadata object as a subclass of the external object class, for each object in the object oriented environment which includes one of the corresponding object oriented computing environment attributes.

During program execution (run time), importing means is responsive to a request from the external computing environment to import external data into the object oriented computing environment. The importing means generates a datalist object, identifies an object oriented computing environment attribute from the datalist object and identifies a corresponding metadata object. The importing means applies the conversion parameters in the corresponding metadata object to the external data, to thereby convert the external data into object oriented data. The importing means places the object oriented data into the corresponding data object which is associated with the corresponding metadata object.

Also during program execution, exporting means is responsive to a request from the object oriented computing environment to export data from an object in the object oriented computing environment to the external computing environment. The exporting means and reads the external data name corresponding to the metadata object from the datalist and identifies an internal name from the datalist. The corresponding metadata object is then identified. The exporting means applies the conversion parameters in the corresponding metadata object to the data from the object, to thereby convert the object oriented data into external data. The external data is formatted into the specific format required by the external computing environment.

During program generation, the method according to the present invention generates the metadata objects as described above so that the object oriented computing environment is capable of responding to import and export requests during execution. During execution, data is imported into the object oriented system by reading the external name and values, generating a datalist object identifying an attribute from the datalist and identifying the corresponding metadata object, and by applying the conversion parameters in the metadata object to the identified data, to thereby convert the external data into object oriented data. The object oriented data is placed into the data object which is associated with the metadata object.

In order to export data to an external environment, the internal name is identified from the datalist and the internal name identified from the datalist. The corresponding metadata object is identified. The conversion parameters in the metadata object are applied to the data from the object to thereby convert the object oriented data into external data. Accordingly, the conversion and validation rules and methods are built into the object oriented computing environment so that rules and methods do not need to be generated for each new external environment which is to communicate with the object oriented environment. Interfaces to new external environments may be added and changed easily with minimal new programming generation and minimal possibility of error.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an object oriented computing environment, an external computing environment and their associated hardware platforms.

FIG. 2 illustrates a block diagram of a system for importing and exporting data according to the present invention.

FIG. 3 illustrates a structure for the datalist class of FIG. 2.

FIGS. 4A and 4B illustrate a structure for the external object class of FIG. 2.

FIG. 5 illustrates operations performed by the importing means and exporting means of FIG. 2 at program generation time.

FIG. 6 illustrates operations performed by the importing means of FIG. 2 at program execution time.

FIG. 7 illustrates operations performed by the exporting means of FIG. 2 at program execution time.

FIGS. 8A and 8B illustrate an example object and a datalist frame for the example object, respectively.

FIG. 9 illustrates a preferred embodiment of a datalist frame.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Prior to describing a system and method for importing and exporting data according to the present invention, a general overview of object oriented computing environments will be provided. A general description of the system and method of the present invention will then be provided, followed by a detailed design description for the system and method for importing and exporting data according to the present invention.

Object Oriented Computing Environment

In an object oriented computing environment, work is accomplished by sending action request messages to an object which contains data. The object will perform the requested action on the data according to its predefined methods. Objects may be grouped into object classes which define the types and meanings of the data, and the action requests (messages) that the objects in the class will honor. The individual objects containing data are called "instances" of the object. Object classes are defined to be subclasses of other classes. Subclasses inherit all of the data characteristics and methods of the parent class. They can add additional data and methods and they can override or redefine any data elements or methods of the parent class.

An object or object class is typically represented schematically by a ring in which the center of the ring contains the frame (data structure) having slots, each of which contains an attribute of the data in the slot. Sectors of the ring are used to indicate the object's methods which encapsulate the frame and may be used to perform actions on the data encapsulated in the frame of object instances.

Referring now to FIG. 1, the hardware and software environment in which the present invention operates will now be described. As shown in FIG. 2, the present invention is a method and system for importing and exporting data between an external computing environment 11 operating on one or more computer platforms 12 and an object oriented computing environment 13 operating on one or more computer platforms 14. It will be understood by those having skill in the art that each of computer platforms 12 and 14 typically include computer hardware units 16 such as a central processing unit (CPU) 17, main memory 18 and an input/output (I/O) interface 19, and may include peripheral components such as a display terminal 21, an input device 22 such as a keyboard or a mouse, nonvolatile data storage devices 23 such as magnetic or optical disks, printers 24 and other peripheral devices. Computer platform 12 or 14 also typically includes microinstruction code 26, and an operating system 28.

As shown in FIG. 1, object oriented computing environment 13 operates on computer platform 14, and external computing environment 11 operates on computer platform 12. However, it will be understood by those having skill in the art that object oriented computing environment 13 and external computing environment 11 may each operate across multiple computer platforms. Alternatively, object oriented computing environment 13 and external computing environment 11 may operate on the same computer platform. Moreover, the external computing environment may operate on a computer platform which is part of a work station which also includes display terminal 21 and input device 22.

As one example, each computer platform 12 and 14 may be a computer having an IBM System 370 architecture. Operating system 28 may be an IBM multiple virtual storage (MVS) operating system. Object oriented computing environment 13 is preferably written in Intermediate C, which is an object oriented dialect of the C computer programming language and is similar to the C++ computer programming language. The design and operation of computer platforms and object oriented computing environments are well known to those having skill in the art and are described, for example in U.S. Pat. Nos. 5,161,225 to Abraham et al. entitled Persistent Stream for Processing Time Consuming and Reusable Queries in an Object Oriented Database Management System; 5,151,987 to Abraham et al. entitled Recovery Objects in an Object Oriented Computing Environment; and 5,161,223 to Abraham entitled Resumeable Batch Query for Processing Time Consuming Queries in an Object Oriented Database Management System, all assigned to the assignee of the present invention, the disclosures of which are hereby incorporated herein by reference, and in numerous textbooks such as Object Oriented Software Construction by Bertrand Meyer, published by Prentice Hall in 1988, the disclosure of which is hereby incorporated herein by reference.

Importing and Exporting System: Overall Design and Operation

Referring now to FIG. 2, a system for importing and exporting data according to the present invention is shown. As shown, the system is included within object oriented computing environment 13 (FIG. 1) and provides import and export of data between object oriented computing