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.*;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionDelta;

The extension deltas are grouped by namespace. There is one registry delta by namespace.
/**
 * The extension deltas are grouped by namespace. There is one registry delta by namespace.
 */
public class RegistryDelta {
	private final Set<IExtensionDelta> extensionDeltas = new HashSet<>(); //the extension deltas (each element indicate the type of the delta)
	private IObjectManager objectManager; //The object manager from which all the objects contained in the deltas will be found.

	RegistryDelta() {
		//Nothing to do
	}

	public int getExtensionDeltasCount() {
		return extensionDeltas.size();
	}

	public IExtensionDelta[] getExtensionDeltas() {
		return extensionDeltas.toArray(new ExtensionDelta[extensionDeltas.size()]);
	}

	public IExtensionDelta[] getExtensionDeltas(String extensionPoint) {
		Collection<IExtensionDelta> selectedExtDeltas = new LinkedList<>();
		for (IExtensionDelta extensionDelta : extensionDeltas) {
			if (extensionDelta.getExtension().getExtensionPointUniqueIdentifier().equals(extensionPoint))
				selectedExtDeltas.add(extensionDelta);
		}
		return selectedExtDeltas.toArray(new IExtensionDelta[selectedExtDeltas.size()]);
	}

	
Params:
extensionPointId – 
extensionId – must not be null/**
	 * @param extensionPointId
	 * @param extensionId must not be null
	 */
	public IExtensionDelta getExtensionDelta(String extensionPointId, String extensionId) {
		for (IExtensionDelta extensionDelta : extensionDeltas) {
			IExtension extension = extensionDelta.getExtension();
			if (extension.getExtensionPointUniqueIdentifier().equals(extensionPointId) && extension.getUniqueIdentifier() != null && extension.getUniqueIdentifier().equals(extensionId))
				return extensionDelta;
		}
		return null;
	}

	void addExtensionDelta(IExtensionDelta extensionDelta) {
		this.extensionDeltas.add(extensionDelta);
		((ExtensionDelta) extensionDelta).setContainingDelta(this);
	}

	@Override
	public String toString() {
		return "\n\tHost " + ": " + extensionDeltas; //$NON-NLS-1$//$NON-NLS-2$
	}

	void setObjectManager(IObjectManager objectManager) {
		this.objectManager = objectManager;
		//TODO May want to add into the existing one here... if it is possible to have batching
	}

	public IObjectManager getObjectManager() {
		return objectManager;
	}
}