extensionpoint

Extension point is a design pattern and APIs in software development, particularly in Eclipse Rich Client Platform (RCP) and other related frameworks. It enables third-party developers to extend or modify the behavior of a system by implementing specific interfaces and registering their implementations with the system.

The concept of extension point was introduced by IBM as a way to allow developers to add new functionality to their systems without modifying the codebase. By defining extension points, developers can expose hooks for others to plug in new features, such as UI components, plugins, or services.

Extension points typically consist of a handler interface, a registry, and a mechanism for registering handlers with the registry. Developers create their own handlers that implement the specified interface and then register them with the system by providing the required information, such as the handler ID and data.

In Eclipse RCP, extension points are used extensively to allow plugins to extend the functionality of the platform. Developers can create their own plugins that implement specific extension points and then install them in the Eclipse environment.

Some of the benefits of using extension points include decoupling the codebase from external dependencies, enabling easy extension and customization, and promoting modularity and reusability. However, the use of extension points can also introduce complexity and dependencies on specific APIs, which needs to be carefully managed.

Overall, extension points provide a powerful mechanism for enabling third-party extensions and customization in software systems, but they require careful design and implementation to be effective.