ModelManager.java

/*******************************************************************************
 * Copyright (c) 2011, 2014 Wind River Systems, Inc. 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:
 * Wind River Systems - initial API and implementation
 *******************************************************************************/
package org.eclipse.tcf.te.tcf.locator.model;

import org.eclipse.core.runtime.Assert;
import org.eclipse.tcf.protocol.Protocol;
import org.eclipse.tcf.te.tcf.locator.interfaces.nodes.ILocatorModel;
import org.eclipse.tcf.te.tcf.locator.interfaces.nodes.IPeerModel;
import org.eclipse.tcf.te.tcf.locator.interfaces.services.ILocatorModelRefreshService;
import org.eclipse.tcf.te.tcf.locator.interfaces.services.IPeerModelRefreshService;
import org.eclipse.tcf.te.tcf.locator.nodes.LocatorModel;
import org.eclipse.tcf.te.tcf.locator.nodes.PeerModel;


/**
 * Helper class to instantiate and initialize the peer and locator model.
 */
public final class ModelManager {
	// Reference to the peer model
	/* default */ static volatile IPeerModel peerModel = null;

	// Reference to the locator model
	/* default */ static volatile ILocatorModel locatorModel = null;

	/**
	 * Returns the shared peer model instance.
	 * <p>
	 * If the shared peer model instance has not been yet initialized,
	 * the method does initialize the shared peer model instance.
	 *
	 * @return The shared peer model.
	 */
	public static IPeerModel getPeerModel() {
		return getPeerModel(false);
	}

	/**
	 * Returns the shared peer model instance.
	 * <p>
	 * If the shared peer model instance has not been yet initialized,
	 * and <code>shutdown</code> is <code>false</code>, the method does
	 * initialize the shared peer model instance.
	 *
	 * @param shutdown <code>True</code> if the method is called during shutdown and
	 *                 the model should not be initialized if not done anyway. <code>
	 *                 false</code> in any other case.
	 *
	 * @return The shared peer model.
	 */
	public static IPeerModel getPeerModel(boolean shutdown) {
		// Access to the locator model must happen in the TCF dispatch thread
		if (peerModel == null && !shutdown) {
			Protocol.invokeAndWait(new Runnable() {
				@Override
				public void run() {
					initialize();
				}
			});
		}
		return peerModel;
	}

	/**
	 * Returns the shared locator model instance.
	 * <p>
	 * If the shared locator model instance has not been yet initialized,
	 * the method does initialize the shared locator model instance.
	 *
	 * @return The shared locator model.
	 */
	public static ILocatorModel getLocatorModel() {
		return getLocatorModel(false);
	}

	/**
	 * Returns the shared locator model instance.
	 * <p>
	 * If the shared locator model instance has not been yet initialized,
	 * and <code>shutdown</code> is <code>false</code>, the method does
	 * initialize the shared locator model instance.
	 *
	 * @param shutdown <code>True</code> if the method is called during shutdown and
	 *                 the model should not be initialized if not done anyway. <code>
	 *                 false</code> in any other case.
	 *
	 * @return The shared locator model.
	 */
	public static ILocatorModel getLocatorModel(boolean shutdown) {
		// Access to the locator model must happen in the TCF dispatch thread
		if (locatorModel == null && !shutdown) {
			Protocol.invokeAndWait(new Runnable() {
				@Override
				public void run() {
					initialize();
				}
			});
		}
		return locatorModel;
	}

	/**
	 * Initialize the root node. Must be called within the TCF dispatch thread.
	 */
	protected static void initialize() {
		Assert.isTrue(Protocol.isDispatchThread(), "Illegal Thread Access"); //$NON-NLS-1$

		// If peer model is set in the mean while, initialize got
		// called twice. Return immediately in this case.
		if (peerModel == null) {
			// Create the model instance
			IPeerModel model = new PeerModel();
			// Apply to the global variable
			peerModel = model;
			// Refresh the model right away
			model.getService(IPeerModelRefreshService.class).refresh(null);
		}

		// If locator model is set in the mean while, initialize got
		// called twice. Return immediately in this case.
		if (locatorModel == null) {
			// Create the model instance
			ILocatorModel model = new LocatorModel();
			// Refresh the model right away
			// Apply to the global variable
			locatorModel = model;
			model.getService(ILocatorModelRefreshService.class).refresh(null);
			((LocatorModel)model).checkLocatorListener();
		}
	}

	/**
	 * Dispose the root node.
	 */
	public static void dispose() {
		if (peerModel != null) {
			// Access to the peer model must happen in the TCF dispatch thread
			Protocol.invokeAndWait(new Runnable() {
				@Override
				public void run() {
					peerModel.dispose();
				}
			});
			peerModel = null;
		}

		if (locatorModel != null) {
			// Access to the locator model must happen in the TCF dispatch thread
			Protocol.invokeAndWait(new Runnable() {
				@Override
				public void run() {
					locatorModel.dispose();
				}
			});
			locatorModel = null;
		}
	}

}