Copyright (c) 2000, 2016 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
    Lars Vogel  - Bug 477789
/*******************************************************************************
 * Copyright (c) 2000, 2016 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
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 477789
 *******************************************************************************/
package org.eclipse.jdt.core.refactoring;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.SubMonitor;

import org.eclipse.core.resources.IFile;

import org.eclipse.text.edits.UndoEdit;

import org.eclipse.jface.text.IDocument;

import org.eclipse.ltk.core.refactoring.Change;
import org.eclipse.ltk.core.refactoring.ChangeDescriptor;
import org.eclipse.ltk.core.refactoring.ContentStamp;
import org.eclipse.ltk.core.refactoring.TextFileChange;

import org.eclipse.jdt.core.ICompilationUnit;

import org.eclipse.jdt.internal.core.manipulation.JavaManipulationPlugin;

A TextFileChange that operates on an ICompilationUnit in the workspace. 
Since:
1.3/**
 * A {@link TextFileChange} that operates on an {@link ICompilationUnit} in the workspace.
 * 
 * @since 1.3
 */
public class CompilationUnitChange extends TextFileChange {

	private final ICompilationUnit fCUnit;

	
The (optional) refactoring descriptor /** The (optional) refactoring descriptor */
	private ChangeDescriptor fDescriptor;

	
Creates a new CompilationUnitChange.
Params:
name – the change's name, mainly used to render the change in the UI
cunit – the compilation unit this change works on/**
	 * Creates a new <code>CompilationUnitChange</code>.
	 *
	 * @param name the change's name, mainly used to render the change in the UI
	 * @param cunit the compilation unit this change works on
	 */
	public CompilationUnitChange(String name, ICompilationUnit cunit) {
		super(name, getFile(cunit));
		Assert.isNotNull(cunit);
		fCUnit= cunit;
		setTextType("java"); //$NON-NLS-1$
	}

	private static IFile getFile(ICompilationUnit cunit) {
		return (IFile) cunit.getResource();
	}

	@Override
	public Object getModifiedElement(){
		return fCUnit;
	}

	
Returns the compilation unit this change works on.
Returns:
the compilation unit this change works on/**
	 * Returns the compilation unit this change works on.
	 *
	 * @return the compilation unit this change works on
	 */
	public ICompilationUnit getCompilationUnit() {
		return fCUnit;
	}

	@Override
	protected IDocument acquireDocument(IProgressMonitor pm) throws CoreException {
		SubMonitor subMonitor= SubMonitor.convert(pm, 2);
		fCUnit.becomeWorkingCopy(subMonitor.split(1));
		Assert.isTrue(fCUnit.isWorkingCopy(), fCUnit.toString());
		return super.acquireDocument(subMonitor.split(1));
	}

	@Override
	protected void releaseDocument(IDocument document, IProgressMonitor pm) throws CoreException {
		boolean isModified= isDocumentModified();
		SubMonitor subMonitor= SubMonitor.convert(pm, 2);
		super.releaseDocument(document, subMonitor.split(1));
		try {
			fCUnit.discardWorkingCopy();
		} finally {
			if (isModified && !isDocumentAcquired()) {
				if (fCUnit.isWorkingCopy())
					fCUnit.reconcile(
							ICompilationUnit.NO_AST,
							false /* don't force problem detection */,
							null /* use primary owner */,
							subMonitor.split(1, SubMonitor.SUPPRESS_BEGINTASK | SubMonitor.SUPPRESS_ISCANCELED));

				else
					fCUnit.makeConsistent(subMonitor.split(1, SubMonitor.SUPPRESS_BEGINTASK | SubMonitor.SUPPRESS_ISCANCELED));
			}
		}
	}

	@Override
	protected Change createUndoChange(UndoEdit edit, ContentStamp stampToRestore) {
		try {
			return new UndoCompilationUnitChange(getName(), fCUnit, edit, stampToRestore, getSaveMode());
		} catch (CoreException e) {
			JavaManipulationPlugin.log(e);
			return null;
		}
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T> T getAdapter(Class<T> adapter) {
		if (ICompilationUnit.class.equals(adapter))
			return (T) fCUnit;
		return super.getAdapter(adapter);
	}

	
Sets the refactoring descriptor for this change.
Params:
descriptor – the descriptor to set, or null to set no descriptor/**
	 * Sets the refactoring descriptor for this change.
	 *
	 * @param descriptor the descriptor to set, or <code>null</code> to set no descriptor
	 */
	public void setDescriptor(ChangeDescriptor descriptor) {
		fDescriptor= descriptor;
	}

	@Override
	public ChangeDescriptor getDescriptor() {
		return fDescriptor;
	}
}