dsf-gdb/org.eclipse.cdt.dsf.gdb.multicorevisualizer.ui/src/org/eclipse/cdt/dsf/gdb/multicorevisualizer/internal/utils/DSFSessionState.java

/*******************************************************************************
 * Copyright (c) 2012 Tilera 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:
 *     William R. Swanson (Tilera Corporation) - initial API and implementation
 *******************************************************************************/

package org.eclipse.cdt.dsf.gdb.multicorevisualizer.internal.utils;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.RejectedExecutionException;

import org.eclipse.cdt.dsf.concurrent.ConfinedToDsfExecutor;
import org.eclipse.cdt.dsf.concurrent.DsfRunnable;
import org.eclipse.cdt.dsf.gdb.multicorevisualizer.internal.ui.MulticoreVisualizerUIPlugin;
import org.eclipse.cdt.dsf.service.DsfServicesTracker;
import org.eclipse.cdt.dsf.service.DsfSession;

/**
 * DSF session state object.
 *
 * Encapsulates and manages DsfSession we're currently tracking.
 */
public class DSFSessionState {
	// --- members ---

	/** Current session ID. */
	protected String m_sessionId;

	/** Current set of session event listeners. */
	protected List<Object> m_sessionListeners;

	/** Services tracker, used to access services. */
	protected DsfServicesTracker m_servicesTracker;

	// --- constructors/destructors ---

	public DSFSessionState(String sessionId) {
		m_sessionId = sessionId;
		m_sessionListeners = new ArrayList<>();
		m_servicesTracker = new DsfServicesTracker(MulticoreVisualizerUIPlugin.getBundleContext(), m_sessionId);
	}

	/** Dispose method. */
	public void dispose() {
		if (m_sessionId != null) {
			removeAllServiceEventListeners();
			m_sessionId = null;
			m_sessionListeners = null;
		}

		if (m_servicesTracker != null) {
			m_servicesTracker.dispose();
			m_servicesTracker = null;
		}
	}

	// --- accessors ---

	/** Returns session ID. */
	public String getSessionID() {
		return m_sessionId;
	}

	// --- listener management ---

	/** Adds a service event listener. */
	public void addServiceEventListener(Object listener) {
		final Object listener_f = listener;
		final DsfSession session_f = getDsfSession();
		if (session_f != null) {
			try {
				session_f.getExecutor().execute(new DsfRunnable() {
					@Override
					public void run() {
						session_f.addServiceEventListener(listener_f, null);
						m_sessionListeners.add(listener_f);
					}
				});
			} catch (RejectedExecutionException e) {
				// Session is shut down.
			}
		}
	}

	/** Removes a service event listener. */
	public void removeServiceEventListener(Object listener) {
		final Object listener_f = listener;
		final DsfSession session_f = getDsfSession();
		if (session_f != null) {
			try {
				session_f.getExecutor().execute(new DsfRunnable() {
					@Override
					public void run() {
						if (m_sessionListeners != null) {
							session_f.removeServiceEventListener(listener_f);
							m_sessionListeners.remove(listener_f);
						}
					}
				});
			} catch (RejectedExecutionException e) {
				// Session is shut down.
			}
		}
	}

	/** Removes all service event listeners. */
	public void removeAllServiceEventListeners() {
		final DsfSession session_f = getDsfSession();
		if (session_f != null) {
			try {
				session_f.getExecutor().execute(new DsfRunnable() {
					@Override
					public void run() {
						if (m_sessionListeners != null) {
							for (Object listener : m_sessionListeners) {
								session_f.removeServiceEventListener(listener);
							}
							m_sessionListeners.clear();
						}
					}
				});
			} catch (RejectedExecutionException e) {
				// Session is shut down.
			}
		}
	}

	// --- methods ---

	/** Gets current DsfSession, if it's still active. */
	protected DsfSession getDsfSession() {
		return DsfSession.getSession(m_sessionId);
	}

	/** Executes DsfRunnable. */
	public void execute(DsfRunnable runnable) {
		try {
			DsfSession session = getDsfSession();
			if (session == null) {
				// TODO: log this?
			} else {
				session.getExecutor().execute(runnable);
			}
		} catch (RejectedExecutionException e) {
			// TODO: log or handle this properly.
			System.err.println("DSFSessionState.execute(): session rejected execution request."); //$NON-NLS-1$
		}
	}

	/** Gets service of the specified type. */
	@ConfinedToDsfExecutor("getDsfSession().getExecutor()")
	public <V> V getService(Class<V> serviceClass) {
		return (m_servicesTracker == null) ? null : m_servicesTracker.getService(serviceClass);
	}
}