This invention pertains to object oriented technology, and particularly to a novel object-oriented system which allows direct access to attributes and direct invocation of methods defined in compiled classes in an interpretive mode.
Object-oriented technology is beginning to enjoy wide-spread popularity in recent years. When using object-oriented technology to build applications, a user must first build the underlying classes. These classes are then used to develop applications in a similar way that integrated circuits are used to build electronic devices. To build these classes and applications, object-oriented languages like Smalltalk and C++ are commonly used. These two languages are unlike each other in one very important aspect. Smalltalk is a fully interpretive language that allows rapid prototyping of classes and applications, but at the expense of performance. On the other hand, programs written in C++ must be compiled and linked before they can be executed. This allows for fast program execution but makes C++ unsuitable for rapid prototyping and debugging.
Given the relative complexity of many object-oriented packages, prototyping and debugging are not simple tasks, but rather involve a considerable amount of effort and a number of iterations in order to perfect the software product. Accordingly, the inability of object-oriented languages to operate in an interpretive fashion makes prototyping and debugging utilizing such non-interpretive software extremely difficult and time-consuming. Conversely, object-oriented technologies which operate in an interpretive manner, but which cannot be compiled, introduces severe performance penalties which utilizing such interpretive object-oriented technologies.
An objective of this invention is to provide a system and method for rapid prototyping of object-oriented applications which can be deployed in a production environment. Rapid prototyping requires an interpreter so that the source code of an application can be executed immediately without requiring compilation. Heretofore, applications executed through an interpreter have unacceptable performance and so cannot be used in a production environment. In the prior art, to have acceptable performance, applications must be compiled first into object code. This code is then deployed in a production environment for execution. But this sacrifices rapid prototyping as the compilation which must be done first is an involved and time-consuming process. Therefore, in accordance with the teachings of this invention, rapid prototyping and yet adequate performance for production deployment is provided by the novel concept in which an application is partially interpreted and partially compiled. With object-oriented technology, classes are commercially available for building applications. These classes are building blocks which are available in pre-compiled form to allow developers to create complex applications without the need to create the classes themselves. By providing a system and a method to "assemble" these pre-compiled classes interpretively to build applications, this invention provides rapid prototyping of source code applications that accesses these classes by interpretively executing the source code during prototyping and debugging, while allowing these source code applications to be deployed in a production environment, since these classes are already compiled and therefore offer acceptable performance.
In accordance with this invention, direct access to attributes and direct invocation of methods defined in the compiled classes is performed in an interpretive mode. When this facility is used with or embedded within an application development environment, it allows an application builder to interactively build prototypes as well as production quality applications rapidly. When the facility is integrated with an object-oriented database, it allows interactive query and data manipulation using compiled classes.