Copyright (c) 2012, 2016 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) 2012, 2016 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.osgi.container;

import java.util.ArrayList;
import java.util.List;
import org.osgi.framework.Bundle;
import org.osgi.framework.wiring.BundleRevision;
import org.osgi.framework.wiring.BundleRevisions;

An implementation of BundleRevisions which represent a Module installed in a container. The ModuleRevisions provides a bridge between the revisions, the module and the container they are associated with. The ModuleRevisions holds the information about the installation of a module in a container such as the module id and location. 
Since:
3.10/**
 * An implementation of {@link BundleRevisions} which represent a 
 * {@link Module} installed in a {@link ModuleContainer container}.
 * The ModuleRevisions provides a bridge between the revisions, the 
 * module and the container they are associated with.  The 
 * ModuleRevisions holds the information about the installation of
 * a module in a container such as the module id and location.
 * @since 3.10
 */
public final class ModuleRevisions implements BundleRevisions {
	private final Object monitor = new Object();
	private final Module module;
	private final ModuleContainer container;
	/* @GuardedBy("monitor") */
	private final List<ModuleRevision> revisions = new ArrayList<>(1);
	/* @GuardedBy("monitor") */
	private boolean uninstalled = false;
	/* @GuardedBy("monitor") */
	private ModuleRevision uninstalledCurrent;

	ModuleRevisions(Module module, ModuleContainer container) {
		this.module = module;
		this.container = container;
	}

	public Module getModule() {
		return module;
	}

	ModuleContainer getContainer() {
		return container;
	}

	@Override
	public Bundle getBundle() {
		return module.getBundle();
	}

	@Override
	public List<BundleRevision> getRevisions() {
		synchronized (monitor) {
			return new ArrayList<BundleRevision>(revisions);
		}
	}

	
Same as getRevisions() except it returns a list of ModuleRevision. 
Returns:
the list of module revisions/**
	 * Same as {@link ModuleRevisions#getRevisions()} except it
	 * returns a list of {@link ModuleRevision}.
	 * @return the list of module revisions
	 */
	public List<ModuleRevision> getModuleRevisions() {
		synchronized (monitor) {
			return new ArrayList<>(revisions);
		}
	}

	
Returns the current revision associated with this revisions. 
Returns:
the current revision associated with this revisions or null if the current revision does not exist./**
	 * Returns the current {@link ModuleRevision revision} associated with this revisions.
	 * 
	 * @return the current {@link ModuleRevision revision} associated with this revisions
	 *     or {@code null} if the current revision does not exist.
	 */
	ModuleRevision getCurrentRevision() {
		synchronized (monitor) {
			if (uninstalled) {
				return uninstalledCurrent;
			}
			if (revisions.isEmpty()) {
				return null;
			}
			return revisions.get(0);
		}
	}

	ModuleRevision addRevision(ModuleRevision revision) {
		synchronized (monitor) {
			revisions.add(0, revision);
		}
		return revision;
	}

	boolean removeRevision(ModuleRevision revision) {
		try {
			synchronized (monitor) {
				return revisions.remove(revision);
			}
		} finally {
			module.cleanup(revision);
		}
	}

	boolean isUninstalled() {
		synchronized (monitor) {
			return uninstalled;
		}
	}

	void uninstall() {
		synchronized (monitor) {
			uninstalled = true;
			// save off the current revision
			if (revisions.isEmpty()) {
				throw new IllegalStateException("Revisions is empty on uninstall!"); //$NON-NLS-1$
			}
			uninstalledCurrent = revisions.get(0);
		}
	}

	@Override
	public String toString() {
		return "moduleID=" + module.getId(); //$NON-NLS-1$
	}
}