UndoEdit.java

/*******************************************************************************
 * Copyright (c) 2012-2015 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ext.java.jdt.text.edits;

import org.eclipse.che.ide.api.editor.text.BadLocationException;
import org.eclipse.che.ide.ext.java.jdt.text.Document;

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

/**
 * 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>.
 *
 * @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);
    }

    /*
     * @see org.eclipse.text.edits.TextEdit#internalAdd(org.eclipse.text.edits.TextEdit )
     */
    void internalAdd(TextEdit child) throws MalformedTreeException {
        throw new MalformedTreeException(null, this, "Cannot add children to an undo edit"); //$NON-NLS-1$
    }

    /*
     * @see org.eclipse.text.edits.MultiTextEdit#aboutToBeAdded(org.eclipse.text.edits .TextEdit)
     */
    void aboutToBeAdded(TextEdit parent) {
        throw new MalformedTreeException(parent, this, "Cannot add an undo edit to another edit"); //$NON-NLS-1$
    }

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

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

    /* @see org.eclipse.text.edits.TextEdit#doCopy() */
    protected TextEdit doCopy() {
        return new UndoEdit(this);
    }

    /* @see TextEdit#accept0 */
    protected void accept0(TextEditVisitor visitor) {
        boolean visitChildren = visitor.visit(this);
        if (visitChildren) {
            acceptChildren(visitor);
        }
    }

    /* @see TextEdit#performDocumentUpdating */
    int performDocumentUpdating(Document document) throws BadLocationException {
        fDelta = 0;
        return fDelta;
    }

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

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

    boolean deleteChildren() {
        return false;
    }
}