3. Plugin System

Plugin Main Class

Each plugin has a main class (Refer to [Write a Simple Plugin] for steps of how to create plugin main class) which should be extended from the AbstractPlugin. Plugin extensions and settings are defined by overriding proper methods of the AbstractPlugin class.

Plugin Dependency

Each plugin will depend on the framewor, ie. the bundle with ID com.pmease.quickbuild, and they can depend on other plugins if you want to extend extension point (see below) defined in those plugins. Refer to [Write a Simple Plugin] for how to declare plugin dependencies.

Extension Point and Extension

Extension point is the point of extension in QuickBuild, and it is defined in the form of interface or abstract class. The framework defined a set of extension points existing in package com.pmease.quickbuild.extensionpoint. Plugin itself can define their own extension points if it wants other plugins to extend its ability. Extension is an implementation of certain extension point, and is defined in a plugin. A plugin can have one or more extensions. Taking the artifact plugin (this plugin extends the system with the ability to publish and display artifacts) for example, the extensions are defined as below:

public class MyPlugin extends AbstractPlugin {
    ...
    public Object[] getExtensions() {
        return new Object[] {
	    new PublishStepTypeProvider() {

                public Class<? extends PublishStep> getPublishStepTypeClass() {
		    return ArtifactPublishStep.class;
                }

            }, 
            new BuildTab() {

                public String getTitle() {
                    return "Artifacts";
                }

                public boolean isApplicable(Build build) {
                    return new File(build.getDir(), ARTIFACTS_DIR).exists();
                }
				
                public BuildPanel getPanel(String panelId, Build build) {
                    return new ArtifactPanel(panelId, build);
                }
            }

    }
    ...
}

Here we defined two extensions: one extends the extension point PublishStepTypeProvider and the other extends the extension point BuildTab.
For those plugins who define their own extension point, the code used to get all extensions for a particular extension point is as below:

Quickbuild.getInstance(PluginManager.class).getExtensions(<extension point class>)

The returned extension collection might be contributed from multiple plugins.

Plugin Setting

Plugin might have settings, for example, Ant plugin has a setting defining path to Ant executable. There are four type of plugin setting, respectively global plugin setting, user level plugin setting, group level plugin setting and configuration level plugin setting:

Plugin Data Storage

Besides plugin setting, plugins might need to generate and save data on the fly when the plugin runs, and use them lately. There are two types of plugin data storages: build storage, and configuration storage.