bundles/org.eclipse.core.runtime/src/org/eclipse/core/internal/registry/Contribution.java

/*******************************************************************************
 * Copyright (c) 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.registry;

import org.eclipse.core.internal.runtime.InternalPlatform;
import org.eclipse.core.runtime.Platform;
import org.osgi.framework.Bundle;

// This object is used to keep track on a bundle basis of the extension and extension points being contributed.
// It is mainly used on removal so we can quickly  find objects to remove.
// Each contribution is made in the context of a namespace. For a regular bundle, the namespace is the symbolic name of the bundle, whereas for a fragment it is the name of its host. 
public class Contribution implements KeyedElement {
	static final int[] EMPTY_CHILDREN = new int[] {0, 0};

	// The actual bundle contributing the object.
	private Bundle contributingBundle;
	private long contributingBundleId;

	// This array stores the identifiers of both the extension points and the extensions.
	// The array has always a minimum size of 2.
	// The first element of the array is the number of extension points and the second the number of extensions. 
	// [numberOfExtensionPoints, numberOfExtensions, extensionPoint#1, extensionPoint#2, extensionPoint..., ext#1, ext#2, ext#3, ... ].
	// The size of the array is 2 + (numberOfExtensionPoints +  numberOfExtensions).
	private int[] children = EMPTY_CHILDREN;
	static final byte EXTENSION_POINT = 0;
	static final byte EXTENSION = 1;

	Contribution(Bundle bundle) {
		contributingBundle = bundle;
		contributingBundleId = bundle.getBundleId();
	}

	Contribution(long id) {
		contributingBundleId = id;
		contributingBundle = InternalPlatform.getDefault().getBundleContext().getBundle(contributingBundleId);
	}

	void setRawChildren(int[] children) {
		this.children = children;
	}

	int[] getRawChildren() {
		return children;
	}

	int[] getExtensions() {
		int[] results = new int[children[EXTENSION]];
		System.arraycopy(children, 2 + children[EXTENSION_POINT], results, 0, children[EXTENSION]);
		return results;
	}

	Bundle getContributingBundle() {
		return contributingBundle;
	}

	int[] getExtensionPoints() {
		int[] results = new int[children[EXTENSION_POINT]];
		System.arraycopy(children, 2, results, 0, children[EXTENSION_POINT]);
		return results;
	}

	String getNamespace() {
		if (contributingBundle == null) // When restored from disk the underlying bundle may have been uninstalled
			throw new IllegalStateException("Internal error in extension registry. The bundle corresponding to this contribution has been uninstalled."); //$NON-NLS-1$
		if (Platform.isFragment(contributingBundle))
			return Platform.getHosts(contributingBundle)[0].getSymbolicName();
		return contributingBundle.getSymbolicName();
	}

	public String toString() {
		return "Contribution: " + contributingBundleId + " in namespace" + getNamespace(); //$NON-NLS-1$ //$NON-NLS-2$
	}

	Bundle getNamespaceBundle() {
		if (contributingBundle == null) // When restored from disk the underlying bundle may have been uninstalled
			throw new IllegalStateException("Internal error in extension registry. The bundle corresponding to this contribution has been uninstalled."); //$NON-NLS-1$
		if (Platform.isFragment(contributingBundle))
			return Platform.getHosts(contributingBundle)[0];
		return contributingBundle;
	}

	//Implements the KeyedElement interface
	public int getKeyHashCode() {
		return getKey().hashCode();
	}

	public Object getKey() {
		return new Long(contributingBundleId);
	}

	public boolean compare(KeyedElement other) {
		return contributingBundleId == ((Contribution) other).contributingBundleId;
	}
}