Copyright (c) 2000, 2006 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, 2006 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.registry;

import java.util.Arrays;
import java.util.Map;
import org.eclipse.core.runtime.IExtensionDelta;
import org.eclipse.core.runtime.IRegistryChangeEvent;

A registry change event implementation. A filter can be specified. In that case, only
deltas for the selected host will be available to clients.
/**
 * A registry change event implementation. A filter can be specified. In that case, only
 * deltas for the selected host will be available to clients.
 */
public final class RegistryChangeEvent implements IRegistryChangeEvent {
	private final String filter;
	private final Map<String, ?> deltas;

	public RegistryChangeEvent(Map<String, ?> deltas, String filter) {
		this.deltas = deltas;
		this.filter = filter;
	}

	private RegistryDelta[] getHostDeltas() {
		// if there is a filter, return only the delta for the selected plug-in
		if (filter != null) {
			RegistryDelta singleDelta = getHostDelta(filter);
			return singleDelta == null ? new RegistryDelta[0] : new RegistryDelta[] {singleDelta};
		}
		// there is no filter - return all deltas
		return deltas.values().toArray(new RegistryDelta[deltas.size()]);
	}

	private RegistryDelta getHostDelta(String pluginId) {
		if (filter != null && !pluginId.equals(filter))
			return null;
		return (RegistryDelta) deltas.get(pluginId);
	}

	@Override
	public IExtensionDelta[] getExtensionDeltas() {
		RegistryDelta[] hostDeltas = getHostDeltas();
		if (hostDeltas.length == 0)
			return new IExtensionDelta[0];
		int extensionDeltasSize = 0;
		for (RegistryDelta hostDelta : hostDeltas) {
			extensionDeltasSize += hostDelta.getExtensionDeltasCount();
		}
		IExtensionDelta[] extensionDeltas = new IExtensionDelta[extensionDeltasSize];
		for (int i = 0, offset = 0; i < hostDeltas.length; i++) {
			IExtensionDelta[] hostExtDeltas = hostDeltas[i].getExtensionDeltas();
			System.arraycopy(hostExtDeltas, 0, extensionDeltas, offset, hostExtDeltas.length);
			offset += hostExtDeltas.length;
		}
		return extensionDeltas;
	}

	@Override
	public IExtensionDelta[] getExtensionDeltas(String hostName) {
		RegistryDelta hostDelta = getHostDelta(hostName);
		if (hostDelta == null)
			return new IExtensionDelta[0];
		return hostDelta.getExtensionDeltas();
	}

	@Override
	public IExtensionDelta[] getExtensionDeltas(String hostName, String extensionPoint) {
		RegistryDelta hostDelta = getHostDelta(hostName);
		if (hostDelta == null)
			return new IExtensionDelta[0];
		return hostDelta.getExtensionDeltas(hostName + '.' + extensionPoint);
	}

	@Override
	public IExtensionDelta getExtensionDelta(String hostName, String extensionPoint, String extension) {
		RegistryDelta hostDelta = getHostDelta(hostName);
		if (hostDelta == null)
			return null;
		return hostDelta.getExtensionDelta(hostName + '.' + extensionPoint, extension);
	}

	@Override
	public String toString() {
		return "RegistryChangeEvent:  " + Arrays.asList(getHostDeltas()); //$NON-NLS-1$
	}
}