Patterns realize their maximum benefit from reuse and distribution. The Reusable Asset Specification (RAS) standards provide a system to easily archive, search for, organize, document, and share pattern assets.
The RAS capability provides a set of features and tools used to create default or specialized types of assets. Patterns are a unique type of RAS asset.
As patterns are created, the required metadata to support the RAS packaging are added to the pattern project. The meta files are known as RAS manifest files. The content of the manifest file is determined by a profile; patterns have their own pattern profile. The profile specifies the type of the meta file used to package and also restore RAS assets. Manifest files are identified by their RMD extension.
When a pattern plug-in project is created, it contains a pattern library and its pattern library manifest file. As one or more patterns are added to the library with the pattern authoring tool, a pattern manifest is added for each pattern. At export, an additional default manifest file is added to package the library with its member patterns.
In addition to the packaging data, the manifest file stores the metadata that enables the RAS features. For example, it stores keywords for searching, short descriptions or instructions for the pattern applier, and group names (known as folders in the Asset Explorer view) for organizing patterns in the Pattern Explorer view and the Asset Explorer view.
All RAS assets are created and stored in the file system or in repositories by using a RAS export utility. Similarly, they are imported and unbundled to recreate the same relationships and structure by using a RAS import utility. Importing a pattern installs it as a plug-in in the workbench.
Repositories are added using the Asset Explorer view. However, the pattern repository is unique because it is always created for you whenever any pattern plug-ins are detected and available to your workspace. All patterns that are installed and can be applied are listed in the pattern repository. Patterns can be listed, for example, in both a local repository and the pattern repository. The local repository represents patterns stored as RAS files and the Pattern Repository represents the installed pattern plug-ins. The Asset Explorer view lists all repositories to which you are connected and all the assets they contain regardless of the asset type.
Common RAS features, such as searching and adding groups (folders), are also available in the Pattern Explorer view. Thus, the pattern user can perform RAS-related functions without using the Asset Explorer view.
As mentioned, RAS assets are created as a result of a RAS export. Pattern projects do not export as pattern plug-ins unless the RAS option to create a deployable asset option is selected. Patterns exported by using the Pattern Authoring view are exported by default as plug-ins. Verification of each pattern in the project is essential before export. A project library that contains patterns that are not logically and semantically correct can be exported as a deployable plug-in. However, after import, the patterns might not appear in the Pattern Explorer view and might not apply correctly. Verification of the pattern is done by testing each pattern in the run-time environment.
Pattern projects that you may want to work on at another time can be saved as projects in your workspace, or exported with the RAS wizard as complete Eclipse projects and imported later.