content: /*******************************************************************************
   * Copyright (c) 2000, 2008 IBM Corporation 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:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.corext.refactoring.util;
  
  import org.eclipse.core.filebuffers.FileBuffers;
  import org.eclipse.core.filebuffers.ITextFileBuffer;
  import org.eclipse.core.filebuffers.LocationKind;
  import org.eclipse.core.resources.IResource;
  import org.eclipse.core.runtime.Assert;
  import org.eclipse.core.runtime.CoreException;
  import org.eclipse.core.runtime.IPath;
  import org.eclipse.core.runtime.NullProgressMonitor;
  import org.eclipse.wst.jsdt.core.IJavaScriptUnit;
  
  
  /**
   * Helper methods to deal with file buffers in refactorings.
   */
  public final class RefactoringFileBuffers {
  
  	/**
  	 * Connects to and acquires a text file buffer for the specified compilation unit.
  	 * <p>
  	 * All text file buffers acquired by a call to {@link RefactoringFileBuffers#acquire(IJavaScriptUnit)}
  	 * must be released using {@link RefactoringFileBuffers#release(IJavaScriptUnit)}.
  	 * </p>
  	 * 
  	 * @param unit the compilation unit to acquire a text file buffer for
  	 * @return the text file buffer, or <code>null</code> if no buffer could be acquired
  	 * @throws CoreException if no buffer could be acquired
  	 */
  	public static ITextFileBuffer acquire(final IJavaScriptUnit unit) throws CoreException {
  		Assert.isNotNull(unit);
  		final IResource resource= unit.getResource();
  		if (resource != null && resource.getType() == IResource.FILE) {
  			final IPath path= resource.getFullPath();
  			FileBuffers.getTextFileBufferManager().connect(path, LocationKind.IFILE, new NullProgressMonitor());
  			return FileBuffers.getTextFileBufferManager().getTextFileBuffer(path, LocationKind.IFILE);
  		}
  		return null;
  	}
  
  	/**
  	 * Returns the text file buffer for the specified compilation unit.
  	 * 
  	 * @param unit the compilation unit whose text file buffer to retrieve
  	 * @return the associated text file buffer, or <code>null</code> if no text file buffer is managed for the compilation unit
  	 */
  	public static ITextFileBuffer getTextFileBuffer(final IJavaScriptUnit unit) {
  		Assert.isNotNull(unit);
  		final IResource resource= unit.getResource();
  		if (resource == null || resource.getType() != IResource.FILE)
  			return null;
  		return FileBuffers.getTextFileBufferManager().getTextFileBuffer(resource.getFullPath(), LocationKind.IFILE);
  	}
  
  	/**
  	 * Releases the text file buffer associated with the compilation unit.
  	 * 
  	 * @param unit the compilation unit whose text file buffer has to be released
  	 * @throws CoreException if the buffer could not be successfully released
  	 */
  	public static void release(final IJavaScriptUnit unit) throws CoreException {
  		Assert.isNotNull(unit);
  		final IResource resource= unit.getResource();
  		if (resource != null && resource.getType() == IResource.FILE)
  			FileBuffers.getTextFileBufferManager().disconnect(resource.getFullPath(), LocationKind.IFILE, new NullProgressMonitor());
  	}
  
  	private RefactoringFileBuffers() {
  		// Not for instantiation
  	}
  }
  