/*******************************************************************************
* 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.text.BadLocationException;
import org.eclipse.che.ide.ext.java.jdt.text.Document;
import org.eclipse.che.ide.ext.java.jdt.text.DocumentEvent;
import org.eclipse.che.ide.ext.java.jdt.text.DocumentListener;
import org.eclipse.che.ide.runtime.Assert;
class UndoCollector implements DocumentListener {
protected UndoEdit undo;
private int fOffset;
private int fLength;
private String fLastCurrentText;
public UndoCollector(TextEdit root) {
fOffset = root.getOffset();
fLength = root.getLength();
}
public void connect(Document document) {
document.addDocumentListener(this);
undo = new UndoEdit();
}
public void disconnect(Document document) {
if (undo != null) {
document.removeDocumentListener(this);
undo.defineRegion(fOffset, fLength);
}
}
/** {@inheritDoc} */
@Override
public void documentChanged(DocumentEvent event) {
fLength += getDelta(event);
}
private static int getDelta(DocumentEvent event) {
String text = event.getText();
return text == null ? -event.getLength() : (text.length() - event.getLength());
}
/** {@inheritDoc} */
@Override
public void documentAboutToBeChanged(DocumentEvent event) {
int offset = event.getOffset();
int currentLength = event.getLength();
String currentText = null;
try {
currentText = event.getDocument().get(offset, currentLength);
} catch (BadLocationException cannotHappen) {
Assert.isTrue(false, "Can't happen"); //$NON-NLS-1$
}
/*
* see https://bugs.eclipse.org/bugs/show_bug.cgi?id=93634
* If the same string is replaced on many documents (e.g. rename
* package), the size of the undo can be reduced by using the same
* String instance in all edits, instead of using the unique String
* returned from IDocument.get(int, int).
*/
if (fLastCurrentText != null && fLastCurrentText.equals(currentText))
currentText = fLastCurrentText;
else
fLastCurrentText = currentText;
String newText = event.getText();
undo.add(new ReplaceEdit(offset, newText != null ? newText.length() : 0, currentText));
}
}