http://www.eclipse.org/platform: File Buffers (Eclipse Foundation) 
Copyright (c) 2007, 2018 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) 2007, 2018 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.filebuffers.manipulation;

import java.util.ArrayList;

import org.eclipse.core.internal.filebuffers.FileBuffersPlugin;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.SubMonitor;
import org.eclipse.core.runtime.jobs.IJobManager;
import org.eclipse.core.runtime.jobs.ISchedulingRule;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.core.runtime.jobs.MultiRule;

import org.eclipse.core.filebuffers.FileBuffers;
import org.eclipse.core.filebuffers.IFileBuffer;
import org.eclipse.core.filebuffers.IFileBufferManager;
import org.eclipse.core.filebuffers.IFileBufferStatusCodes;
import org.eclipse.core.filebuffers.ITextFileBuffer;
import org.eclipse.core.filebuffers.ITextFileBufferManager;
import org.eclipse.core.filebuffers.LocationKind;



A GenericFileBufferOperationRunner executes IFileBufferOperation. The runner takes care of all aspects that are not operation specific. 

This class is not intended to be subclassed. Clients instantiate this class.



See Also:
Since:3.3
@noextendThis class is not intended to be subclassed by clients.
/**
 * A <code>GenericFileBufferOperationRunner</code> executes
 * {@link org.eclipse.core.filebuffers.manipulation.IFileBufferOperation}.
 * The runner takes care of all aspects that are not operation specific.
 * <p>
 * This class is not intended to be subclassed. Clients instantiate this class.
 * </p>
 *
 * @see org.eclipse.core.filebuffers.manipulation.IFileBufferOperation
 * @since 3.3
 * @noextend This class is not intended to be subclassed by clients.
 */
public class GenericFileBufferOperationRunner {

	
The validation context 
/** The validation context */
	private final Object fValidationContext;
	
The file buffer manager 
/** The file buffer manager */
	private final IFileBufferManager fFileBufferManager;

	
The lock for waiting for completion of computation in the UI thread. 
/** The lock for waiting for completion of computation in the UI thread. */
	private final Object fCompletionLock= new Object();
	
The flag indicating completion of computation in the UI thread. 
/** The flag indicating completion of computation in the UI thread. */
	private transient boolean fIsCompleted;
	
The exception thrown during the computation in the UI thread. 
/** The exception thrown during the computation in the UI thread. */
	private transient Throwable fThrowable;


	
Creates a new file buffer operation runner.

Params:
  • fileBufferManager – the file buffer manager
  • validationContext – the validationContext
/**
	 * Creates a new file buffer operation runner.
	 *
	 * @param fileBufferManager the file buffer manager
	 * @param validationContext the validationContext
	 */
	public GenericFileBufferOperationRunner(IFileBufferManager fileBufferManager, Object validationContext) {
		fFileBufferManager= fileBufferManager;
		fValidationContext= validationContext;
	}

	
Executes the given operation for all file buffers specified by the given locations.

Params:
  • locations – the file buffer locations
  • operation – the operation to be performed
  • monitor – the progress monitor, or null if progress reporting is not desired
Throws:
/**
	 * Executes the given operation for all file buffers specified by the given locations.
	 *
	 * @param locations the file buffer locations
	 * @param operation the operation to be performed
	 * @param monitor the progress monitor, or <code>null</code> if progress reporting is not desired
	 * @throws CoreException in case of error
	 * @throws OperationCanceledException in case the execution get canceled
	 */
	public void execute(IPath[] locations, final IFileBufferOperation operation, IProgressMonitor monitor) throws CoreException, OperationCanceledException {
		final int size= locations.length;
		SubMonitor subMonitor= SubMonitor.convert(monitor, operation.getOperationName(), size * 200);
		try {
			IFileBuffer[] fileBuffers= createFileBuffers(locations, subMonitor.split(size * 10));

			IFileBuffer[] fileBuffers2Save= findFileBuffersToSave(fileBuffers);
			fFileBufferManager.validateState(fileBuffers2Save, subMonitor.split(size * 10), fValidationContext);
			if (!isCommitable(fileBuffers2Save))
			{
				throw new OperationCanceledException();
			}

			IFileBuffer[] unsynchronizedFileBuffers= findUnsynchronizedFileBuffers(fileBuffers);
			performOperation(unsynchronizedFileBuffers, operation, subMonitor.split(size * 40));

			final IFileBuffer[] synchronizedFileBuffers= findSynchronizedFileBuffers(fileBuffers);
			fIsCompleted= false;
			fThrowable= null;
			synchronized (fCompletionLock) {

				executeInContext(() -> {
					synchronized (fCompletionLock) {
						try {
							SafeRunner.run(new ISafeRunnable() {
								@Override
								public void handleException(Throwable throwable) {
									fThrowable= throwable;
								}

								@Override
								public void run() throws Exception {
									performOperation(synchronizedFileBuffers, operation, subMonitor.split(50));
								}
							});
						} finally {
							fIsCompleted= true;
							fCompletionLock.notifyAll();
						}
					}
				});

				while (!fIsCompleted) {
					try {
						fCompletionLock.wait(500);
					} catch (InterruptedException x) {
					}
				}
			}

			if (fThrowable != null) {
				if (fThrowable instanceof CoreException)
					throw (CoreException) fThrowable;
				throw new CoreException(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, IFileBufferStatusCodes.CONTENT_CHANGE_FAILED, fThrowable.getLocalizedMessage(), fThrowable));
			}

			commit(fileBuffers2Save, subMonitor.split(size * 80));

		} finally {
			releaseFileBuffers(locations, subMonitor.split(size * 10));
		}
	}

	private void performOperation(IFileBuffer fileBuffer, IFileBufferOperation operation, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {
		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, 100);
		ISchedulingRule rule= fileBuffer.computeCommitRule();
		IJobManager manager= Job.getJobManager();
		manager.beginRule(rule, subMonitor.split(1));
		String name= fileBuffer.getLocation().lastSegment();
		subMonitor.setTaskName(name);
		operation.run(fileBuffer, subMonitor.split(99));
		manager.endRule(rule);
	}

	private void performOperation(IFileBuffer[] fileBuffers, IFileBufferOperation operation, IProgressMonitor progressMonitor) throws CoreException, OperationCanceledException {
		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, fileBuffers.length);
		for (IFileBuffer fileBuffer : fileBuffers) {
			performOperation(fileBuffer, operation, subMonitor.split(1));
		}
	}

	private void executeInContext(Runnable runnable) {
		ITextFileBufferManager fileBufferManager= FileBuffers.getTextFileBufferManager();
		fileBufferManager.execute(runnable);
	}

	private IFileBuffer[] findUnsynchronizedFileBuffers(IFileBuffer[] fileBuffers) {
		ArrayList<IFileBuffer> list= new ArrayList<>();
		for (IFileBuffer fileBuffer : fileBuffers) {
			if (!fileBuffer.isSynchronizationContextRequested()) {
				list.add(fileBuffer);
			}
		}
		return list.toArray(new IFileBuffer[list.size()]);
	}

	private IFileBuffer[] findSynchronizedFileBuffers(IFileBuffer[] fileBuffers) {
		ArrayList<IFileBuffer> list= new ArrayList<>();
		for (IFileBuffer fileBuffer : fileBuffers) {
			if (fileBuffer.isSynchronizationContextRequested())
				list.add(fileBuffer);
		}
		return list.toArray(new IFileBuffer[list.size()]);
	}

	private IFileBuffer[] createFileBuffers(IPath[] locations, IProgressMonitor progressMonitor) throws CoreException {

		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, FileBuffersMessages.FileBufferOperationRunner_task_connecting, locations.length);
		try {
			IFileBuffer[] fileBuffers= new ITextFileBuffer[locations.length];
			for (int i= 0; i < locations.length; i++) {
				fFileBufferManager.connect(locations[i], LocationKind.NORMALIZE, subMonitor.split(1));
				fileBuffers[i]= fFileBufferManager.getFileBuffer(locations[i], LocationKind.NORMALIZE);
			}
			return fileBuffers;

		} catch (CoreException x) {
			try {
				releaseFileBuffers(locations, new NullProgressMonitor());
			} catch (CoreException e) {
			}
			throw x;
		}
	}

	private void releaseFileBuffers(IPath[] locations, IProgressMonitor progressMonitor) throws CoreException {
		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, FileBuffersMessages.FileBufferOperationRunner_task_disconnecting, locations.length);
		final ITextFileBufferManager fileBufferManager= FileBuffers.getTextFileBufferManager();
		for (IPath location : locations) {
			fileBufferManager.disconnect(location, LocationKind.NORMALIZE, subMonitor.split(1));
		}
	}

	private IFileBuffer[] findFileBuffersToSave(IFileBuffer[] fileBuffers) {
		ArrayList<IFileBuffer> list= new ArrayList<>();
		for (IFileBuffer fileBuffer : fileBuffers) {
			IFileBuffer buffer= fileBuffer;
			if (!buffer.isDirty())
				list.add(buffer);
		}
		return list.toArray(new IFileBuffer[list.size()]);
	}

	private boolean isCommitable(IFileBuffer[] fileBuffers) {
		for (IFileBuffer fileBuffer : fileBuffers) {
			if (!fileBuffer.isCommitable()) {
				return false;
			}
		}
		return true;
	}

	protected ISchedulingRule computeCommitRule(IFileBuffer[] fileBuffers) {
		ArrayList<ISchedulingRule> list= new ArrayList<>();
		for (IFileBuffer fileBuffer : fileBuffers) {
			ISchedulingRule rule= fileBuffer.computeCommitRule();
			if (rule != null)
				list.add(rule);
		}
		ISchedulingRule[] rules= new ISchedulingRule[list.size()];
		list.toArray(rules);
		return new MultiRule(rules);
	}

	protected void commit(final IFileBuffer[] fileBuffers, final IProgressMonitor progressMonitor) throws CoreException {
		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, 2);
		ISchedulingRule rule= computeCommitRule(fileBuffers);
		Job.getJobManager().beginRule(rule, subMonitor.split(1));
		try {
			doCommit(fileBuffers, subMonitor.split(1));
		} finally {
			Job.getJobManager().endRule(rule);
		}
	}

	protected void doCommit(final IFileBuffer[] fileBuffers, IProgressMonitor progressMonitor) throws CoreException {
		SubMonitor subMonitor= SubMonitor.convert(progressMonitor, FileBuffersMessages.FileBufferOperationRunner_task_committing, fileBuffers.length);
		for (IFileBuffer fileBuffer : fileBuffers) {
			fileBuffer.commit(subMonitor.split(1), true);
		}
	}

}