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.text.edits;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;


This class encapsulates the reverse changes of an executed text
edit tree. To apply an undo memento to a document use method
apply(IDocument).

Clients can't add additional children to an undo edit nor can they
add an undo edit as a child to another edit. Doing so results in
both cases in a MalformedTreeException.

Since:
3.0
@noinstantiate
This class is not intended to be instantiated by clients./**
 * This class encapsulates the reverse changes of an executed text
 * edit tree. To apply an undo memento to a document use method
 * <code>apply(IDocument)</code>.
 * <p>
 * Clients can't add additional children to an undo edit nor can they
 * add an undo edit as a child to another edit. Doing so results in
 * both cases in a <code>MalformedTreeException</code>.
 * </p>
 *
 * @since 3.0
 * @noinstantiate This class is not intended to be instantiated by clients.
 */
public final class UndoEdit extends TextEdit {

	UndoEdit() {
		super(0, Integer.MAX_VALUE);
	}

	private UndoEdit(UndoEdit other) {
		super(other);
	}

	@Override
	void internalAdd(TextEdit child) throws MalformedTreeException {
		throw new MalformedTreeException(null, this, TextEditMessages.getString("UndoEdit.no_children")); //$NON-NLS-1$
	}

	@Override
	void aboutToBeAdded(TextEdit parent) {
		throw new MalformedTreeException(parent, this, TextEditMessages.getString("UndoEdit.can_not_be_added")); //$NON-NLS-1$
	}

	@Override
	UndoEdit dispatchPerformEdits(TextEditProcessor processor) throws BadLocationException {
		return processor.executeUndo();
	}

	@Override
	void dispatchCheckIntegrity(TextEditProcessor processor) throws MalformedTreeException {
		processor.checkIntegrityUndo();
	}

	@Override
	protected TextEdit doCopy() {
		return new UndoEdit(this);
	}

	@Override
	protected void accept0(TextEditVisitor visitor) {
		boolean visitChildren= visitor.visit(this);
		if (visitChildren) {
			acceptChildren(visitor);
		}
	}

	@Override
	int performDocumentUpdating(IDocument document) throws BadLocationException {
		fDelta= 0;
		return fDelta;
	}

	void add(ReplaceEdit edit) {
		List<TextEdit> children= internalGetChildren();
		if (children == null) {
			children= new ArrayList<>(2);
			internalSetChildren(children);
		}
		children.add(edit);
	}

	void defineRegion(int offset, int length) {
		internalSetOffset(offset);
		internalSetLength(length);
	}

	@Override
	boolean deleteChildren() {
		return false;
	}
}