Copyright (c) 2000, 2008 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.adapter;

import java.util.Iterator;
import java.util.List;
import org.eclipse.core.internal.runtime.AdapterManager;
import org.eclipse.core.internal.runtime.IAdapterManagerProvider;
import org.eclipse.core.runtime.*;

Portions of the AdapterManager that deal with the Eclipse extension registry
were moved into this class.
/**
 * Portions of the AdapterManager that deal with the Eclipse extension registry
 * were moved into this class.
 */
public final class AdapterManagerListener implements IRegistryEventListener, IAdapterManagerProvider {
	public static final String ADAPTER_POINT_ID = "org.eclipse.core.runtime.adapters"; //$NON-NLS-1$

	private final AdapterManager theAdapterManager;

	
Constructs a new adapter manager.
/**
	 * Constructs a new adapter manager.
	 */
	public AdapterManagerListener() {
		theAdapterManager = AdapterManager.getDefault();
		theAdapterManager.registerLazyFactoryProvider(this);
	}

	
Loads adapters registered with the adapters extension point from
the plug-in registry.  Note that the actual factory implementations
are loaded lazily as they are needed.
/**
	 * Loads adapters registered with the adapters extension point from
	 * the plug-in registry.  Note that the actual factory implementations
	 * are loaded lazily as they are needed.
	 */
	@Override
	public boolean addFactories(AdapterManager adapterManager) {
		IExtensionPoint point = RegistryFactory.getRegistry().getExtensionPoint(ADAPTER_POINT_ID);
		if (point == null)
			return false;

		boolean factoriesAdded = false;
		IExtension[] extensions = point.getExtensions();
		for (IExtension extension : extensions) {
			IConfigurationElement[] elements = extension.getConfigurationElements();
			for (IConfigurationElement element : elements) {
				AdapterFactoryProxy proxy = AdapterFactoryProxy.createProxy(element);
				if (proxy != null) {
					adapterManager.registerFactory(proxy, proxy.getAdaptableType());
					factoriesAdded = true;
				}
			}
		}
		RegistryFactory.getRegistry().addListener(this, ADAPTER_POINT_ID);
		return factoriesAdded;
	}

	private void registerExtension(IExtension extension) {
		IConfigurationElement[] elements = extension.getConfigurationElements();
		for (IConfigurationElement element : elements) {
			AdapterFactoryProxy proxy = AdapterFactoryProxy.createProxy(element);
			if (proxy != null)
				theAdapterManager.registerFactory(proxy, proxy.getAdaptableType());
		}
	}

	@Override
	public synchronized void added(IExtension[] extensions) {
		for (IExtension extension : extensions) {
			registerExtension(extension);
		}
		theAdapterManager.flushLookup();
	}

	@Override
	public synchronized void removed(IExtension[] extensions) {
		theAdapterManager.flushLookup();
		for (IExtension extension : extensions) {
			for (Iterator<List<IAdapterFactory>> it = theAdapterManager.getFactories().values().iterator(); it.hasNext();) {
				for (Iterator<IAdapterFactory> it2 = (it.next()).iterator(); it2.hasNext();) {
					IAdapterFactory factory = it2.next();
					if (!(factory instanceof AdapterFactoryProxy))
						continue;
					if (((AdapterFactoryProxy) factory).originatesFrom(extension)) {
						it2.remove();
					}
				}
			}
		}
	}

	@Override
	public synchronized void added(IExtensionPoint[] extensionPoints) {
		// nothing to do
	}

	@Override
	public synchronized void removed(IExtensionPoint[] extensionPoints) {
		// all extensions should have been removed by this point by #removed(IExtension[] extensions)
		// nothing to do
	}

	/*
	 * Shuts down the listener by removing the registry change listener. Should only be
	 * invoked during platform shutdown.
	 */
	public synchronized void stop() {
		RegistryFactory.getRegistry().removeListener(this);
	}
}