Copyright (c) 2000, 2008 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) 2000, 2008 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.ltk.core.refactoring;

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

import org.eclipse.ltk.internal.core.refactoring.RefactoringCoreMessages;

A refactoring change that does nothing. The reverse change of a
NullChange is a NullChange.

Note: this class is not intended to be extended by clients.

Since:
3.0
@noextend
This class is not intended to be subclassed by clients./**
 * A refactoring change that does nothing. The reverse change of a
 * <code>NullChange</code> is a <code>NullChange</code>.
 * <p>
 * Note: this class is not intended to be extended by clients.
 * </p>
 *
 * @since 3.0
 *
 * @noextend This class is not intended to be subclassed by clients.
 */
public class NullChange extends Change {

	private String fName;

	
Creates a new NullChange with a default name.
/**
	 * Creates a new <code>NullChange</code> with a default name.
	 */
	public NullChange() {
		this(RefactoringCoreMessages.NullChange_name);
	}

	
Creates a new NullChange with the given name.
Params:
name – the human readable name of this change/**
	 * Creates a new <code>NullChange</code> with the given name.
	 *
	 * @param name the human readable name of this change
	 */
	public NullChange(String name) {
		Assert.isNotNull(name);
		fName= name;
	}

	@Override
	public String getName() {
		return fName;
	}

	@Override
	public void initializeValidationData(IProgressMonitor pm) {
		// do nothing
	}

	@Override
	public RefactoringStatus isValid(IProgressMonitor pm) throws CoreException {
		return new RefactoringStatus();
	}

	@Override
	public Change perform(IProgressMonitor pm) throws CoreException {
		return new NullChange();
	}

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