dsf/org.eclipse.cdt.dsf/src/org/eclipse/cdt/dsf/debug/service/command/BufferedCommandControl.java

/*******************************************************************************
 * Copyright (c) 2009, 2012 Wind River Systems 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:
 *     Wind River Systems - initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.dsf.debug.service.command;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.cdt.dsf.concurrent.DataRequestMonitor;
import org.eclipse.cdt.dsf.concurrent.DsfExecutor;
import org.eclipse.cdt.dsf.concurrent.DsfRunnable;
import org.eclipse.cdt.dsf.concurrent.ImmediateExecutor;

/**
 * A command control which delays the <strong>results</strong> of commands
 * sent to a command control, as well as events from the command control.
 * The delay is specified in the constructor using a number of executor
 * dispatch cycles.
 *
 * @since 2.1
 */
public class BufferedCommandControl implements ICommandControl {

	private DsfExecutor fExecutor;
	private ICommandControl fControlDelegate;
	private int fDepth;

	private ICommandListener fCommandListener = new ICommandListener() {
		@Override
		public void commandQueued(ICommandToken token) {
			for (ICommandListener processor : fCommandProcessors) {
				processor.commandQueued(token);
			}
		}

		@Override
		public void commandRemoved(ICommandToken token) {
			for (ICommandListener processor : fCommandProcessors) {
				processor.commandRemoved(token);
			}
		}

		@Override
		public void commandSent(final ICommandToken token) {
			for (ICommandListener processor : fCommandProcessors) {
				processor.commandSent(token);
			}
		}

		@Override
		public void commandDone(final ICommandToken token, final ICommandResult result) {
			buffer(fDepth, new DsfRunnable() {
				@Override
				public void run() {
					for (ICommandListener processor : fCommandProcessors) {
						processor.commandDone(token, result);
					}
				}
			});
		}
	};

	private IEventListener fEventListener = new IEventListener() {
		@Override
		public void eventReceived(final Object output) {
			buffer(fDepth, new DsfRunnable() {
				@Override
				public void run() {
					for (IEventListener processor : fEventProcessors) {
						processor.eventReceived(output);
					}
				}
			});
		}
	};

	private final List<ICommandListener> fCommandProcessors = new ArrayList<>();
	private final List<IEventListener> fEventProcessors = new ArrayList<>();

	public BufferedCommandControl(ICommandControl controlDelegate, DsfExecutor executor, int depth) {
		fControlDelegate = controlDelegate;
		fExecutor = executor;
		fDepth = depth;
		assert fDepth > 0;
	}

	@Override
	public void addCommandListener(ICommandListener listener) {
		if (fCommandProcessors.isEmpty()) {
			fControlDelegate.addCommandListener(fCommandListener);
		}
		fCommandProcessors.add(listener);
	}

	@Override
	public void removeCommandListener(ICommandListener listener) {
		fCommandProcessors.remove(listener);
		if (fCommandProcessors.isEmpty()) {
			fControlDelegate.removeCommandListener(fCommandListener);
		}
	}

	@Override
	public void addEventListener(IEventListener listener) {
		if (fEventProcessors.isEmpty()) {
			fControlDelegate.addEventListener(fEventListener);
		}
		fEventProcessors.add(listener);
	}

	@Override
	public void removeEventListener(IEventListener listener) {
		fEventProcessors.remove(listener);
		if (fEventProcessors.isEmpty()) {
			fControlDelegate.removeEventListener(fEventListener);
		}
	}

	@Override
	public <V extends ICommandResult> ICommandToken queueCommand(final ICommand<V> command,
			final DataRequestMonitor<V> rm) {
		return fControlDelegate.queueCommand(command, new DataRequestMonitor<V>(ImmediateExecutor.getInstance(), rm) {
			@Override
			protected void handleCompleted() {
				buffer(fDepth, new DsfRunnable() {
					@Override
					public void run() {
						rm.setData(getData());
						rm.setStatus(getStatus());
						rm.done();
					}
				});
			}
		});
	}

	@Override
	public void removeCommand(ICommandToken token) {
		fControlDelegate.removeCommand(token);
	}

	private void buffer(final int depth, final DsfRunnable runnable) {
		if (depth == 0) {
			runnable.run();
		} else {
			fExecutor.execute(new DsfRunnable() {
				@Override
				public void run() {
					buffer(depth - 1, runnable);
				}
			});
		}
	}

}