/*******************************************************************************
 * 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.dltk.ui.editor.saveparticipant;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.dltk.core.ISourceModule;
import org.eclipse.jface.text.IRegion;

/**
 * This <code>IPostSaveListener</code> is informed when a compilation unit is
 * saved through the {@link CompilationUnitDocumentProvider}.
 * <p>
 * In oder to get notified the listener must be registered with the
 * {@link SaveParticipantRegistry} and be enabled on the save participant
 * preference page.
 * </p>
 * <p>
 * The notification order of post save listeners is unspecified.
 * </p>
 * <p>
 * Clients may implement this interface.
 * </p>
 * 
 * @see SaveParticipantDescriptor
 * @see CompilationUnitDocumentProvider
 * @since 3.0
 */
public interface IPostSaveListener {

	/**
	 * A human readable name of this listener.
	 * 
	 * @return the name
	 */
	String getName();

	/**
	 * The unique id of this listener.
	 * 
	 * @return a non-empty id
	 */
	String getId();

	/**
	 * Called when a compilation unit is saved.
	 * <p>
	 * 
	 * @param context
	 *            the context in which the compilation unit is saved
	 * @return true if this save participant needs to be informed
	 */
	boolean isEnabled(ISourceModule compilationUnit);

	/**
	 * Does this save participant need to be informed about the changed regions
	 * in the given compilation unit on next call to
	 * {@link #saved(ICompilationUnit, IRegion[], IProgressMonitor)}?
	 * <p>
	 * <strong>This should return <code>false</code> whenever possible because
	 * calculating changed regions is expensive.</strong>
	 * </p>
	 * 
	 * @param compilationUnit
	 *            the compilation unit which is about to be saved
	 * @return true if changed regions should be computed
	 * @throws CoreException
	 *             if something went wrong
	 */
	boolean needsChangedRegions(ISourceModule compilationUnit)
			throws CoreException;

	/**
	 * Informs this post save listener that the given
	 * <code>compilationUnit</code> has been saved by the
	 * {@link CompilationUnitDocumentProvider}. The listener is allowed to
	 * modify the given compilation unit and to open a dialog.
	 * <p>
	 * <em>Every implementor of this method must strictly obey these rules:</em>
	 * <ul>
	 * <li>not touch any file other than the given <code>compilationUnit</code>
	 * which is already locked by a scheduling rule</li>
	 * <li>changing the scheduling rule or posting a new job is not allowed</li>
	 * <li>it is not allowed to save the given <code>compilationUnit</code></li>
	 * <li>it must be able to deal with unsaved resources and with compilation
	 * units which are not on the Java build path</li>
	 * <li>must not assume to be called in the UI thread</li>
	 * <li>should be as fast as possible since this code is executed every time
	 * the <code>compilationUnit</code> is saved</li>
	 * </ul>
	 * The compilation unit document provider can disable a listener that
	 * violates any of the above rules.
	 * </p>
	 * 
	 * @param compilationUnit
	 *            the compilation unit which was saved
	 * @param changedRegions
	 *            the regions where the compilationUnit has changed since the
	 *            last save or <b>null</b> if
	 *            </code>requiresChangedRegions</code> did return
	 *            <code>false</code>. The changed regions do not include changes
	 *            introduced by other save participants.
	 * @param monitor
	 *            the progress monitor for reporting progress
	 * @throws CoreException
	 *             if something went wrong
	 * 
	 * @see org.eclipse.dltk.internal.ui.editor.SourceModuleDocumentProvider
	 */
	void saved(ISourceModule compilationUnit, IRegion[] changedRegions,
			IProgressMonitor monitor) throws CoreException;

}