IndexerManager.java example

Explorer
org.eclipse.dltk.core-master
/*******************************************************************************
 * Copyright (c) 2009 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
 *     Zend Technologies
 *******************************************************************************/
package org.eclipse.dltk.internal.core.index2;

import java.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.dltk.core.DLTKCore;
import org.eclipse.dltk.core.index2.AbstractIndexer;
import org.eclipse.dltk.core.index2.IIndexer;
import org.eclipse.dltk.core.index2.IIndexerParticipant;

/**
 * Indexer instances manager
 * 
 * @author michael
 * 
 */
public class IndexerManager {

	private static final String PARTICIPANT_POINT = DLTKCore.PLUGIN_ID
			+ ".indexerParticipant"; //$NON-NLS-1$
	private static final String INDEXER_POINT = DLTKCore.PLUGIN_ID + ".indexer"; //$NON-NLS-1$
	private static final String INDEXER_ATTR = "indexer"; //$NON-NLS-1$
	private static final String PARTICIPANT_ELEMENT = "indexerParticipant"; //$NON-NLS-1$
	private static final String CLASS_ATTR = "class"; //$NON-NLS-1$
	private static final String NATURE_ATTR = "nature"; //$NON-NLS-1$
	private static final String ID_ATTR = "id"; //$NON-NLS-1$
	private static final String TARGET_ID_ATTR = "targetId"; //$NON-NLS-1$

	private static IConfigurationElement indexerElement;
	private static AbstractIndexer indexer;
	private static Map<String, Map<String, IConfigurationElement>> indexerParticipants = new HashMap<String, Map<String, IConfigurationElement>>();

	static {
		IConfigurationElement[] elements = Platform.getExtensionRegistry()
				.getConfigurationElementsFor(INDEXER_POINT);
		for (IConfigurationElement element : elements) {
			String name = element.getName();
			if (INDEXER_ATTR.equals(name)) {
				indexerElement = element;
				break;
			}
		}

		elements = Platform.getExtensionRegistry().getConfigurationElementsFor(
				PARTICIPANT_POINT);
		for (IConfigurationElement element : elements) {
			String name = element.getName();
			if (PARTICIPANT_ELEMENT.equals(name)) {
				String targetId = element.getAttribute(TARGET_ID_ATTR);
				String nature = element.getAttribute(NATURE_ATTR);
				if (!indexerParticipants.containsKey(targetId)) {
					indexerParticipants.put(targetId,
							new HashMap<String, IConfigurationElement>());
				}
				indexerParticipants.get(targetId).put(nature, element);
			}
		}
	}

	public static IIndexer getIndexer() {
		if (indexer == null && indexerElement != null) {
			try {
				indexer = (AbstractIndexer) indexerElement
						.createExecutableExtension(CLASS_ATTR);
				indexer.setId(indexerElement.getAttribute(ID_ATTR));
			} catch (CoreException e) {
				DLTKCore.error(e);
			}
		}
		return indexer;
	}

	public static IIndexerParticipant getIndexerParticipant(IIndexer indexer,
			String natureId) {

		Map<String, IConfigurationElement> participants = indexerParticipants
				.get(((AbstractIndexer) indexer).getId());
		if (participants != null) {
			IConfigurationElement element = participants.get(natureId);
			if (element != null) {
				try {
					return (IIndexerParticipant) element
							.createExecutableExtension(CLASS_ATTR);
				} catch (CoreException e) {
					if (DLTKCore.DEBUG) {
						e.printStackTrace();
					}
				}
			}
		}
		return null;
	}
}