/*******************************************************************************
* Copyright (c) 2007 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
******************************************************************************/
package org.eclipse.core.databinding;
import java.util.Collections;
import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.list.IListChangeListener;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.ListChangeEvent;
import org.eclipse.core.databinding.observable.list.ListDiff;
import org.eclipse.core.databinding.observable.list.ListDiffEntry;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.core.databinding.observable.value.WritableValue;
import org.eclipse.core.internal.databinding.BindingStatus;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.Status;
/**
* @since 1.0
*
*/
public class ListBinding extends Binding {
private UpdateListStrategy targetToModel;
private UpdateListStrategy modelToTarget;
private IObservableValue validationStatusObservable;
private boolean updatingTarget;
private boolean updatingModel;
private IListChangeListener targetChangeListener = new IListChangeListener() {
public void handleListChange(ListChangeEvent event) {
if (!updatingTarget) {
doUpdate((IObservableList) getTarget(),
(IObservableList) getModel(), event.diff,
targetToModel, false, false);
}
}
};
private IListChangeListener modelChangeListener = new IListChangeListener() {
public void handleListChange(ListChangeEvent event) {
if (!updatingModel) {
doUpdate((IObservableList) getModel(),
(IObservableList) getTarget(), event.diff,
modelToTarget, false, false);
}
}
};
/**
* @param target
* @param model
* @param modelToTargetStrategy
* @param targetToModelStrategy
*/
public ListBinding(IObservableList target, IObservableList model,
UpdateListStrategy targetToModelStrategy,
UpdateListStrategy modelToTargetStrategy) {
super(target, model);
this.targetToModel = targetToModelStrategy;
this.modelToTarget = modelToTargetStrategy;
if ((targetToModel.getUpdatePolicy() & UpdateValueStrategy.POLICY_UPDATE) != 0) {
target.addListChangeListener(targetChangeListener);
} else {
targetChangeListener = null;
}
if ((modelToTarget.getUpdatePolicy() & UpdateValueStrategy.POLICY_UPDATE) != 0) {
model.addListChangeListener(modelChangeListener);
} else {
modelChangeListener = null;
}
}
public IObservableValue getValidationStatus() {
return validationStatusObservable;
}
protected void preInit() {
validationStatusObservable = new WritableValue(context
.getValidationRealm(), Status.OK_STATUS, IStatus.class);
}
protected void postInit() {
if (modelToTarget.getUpdatePolicy() == UpdateListStrategy.POLICY_UPDATE) {
updateModelToTarget();
}
if (targetToModel.getUpdatePolicy() != UpdateListStrategy.POLICY_NEVER) {
validateTargetToModel();
}
}
public void updateModelToTarget() {
final IObservableList modelList = (IObservableList) getModel();
modelList.getRealm().exec(new Runnable() {
public void run() {
ListDiff diff = Diffs.computeListDiff(Collections.EMPTY_LIST,
modelList);
doUpdate(modelList, (IObservableList) getTarget(), diff,
modelToTarget, true, true);
}
});
}
public void updateTargetToModel() {
final IObservableList targetList = (IObservableList) getTarget();
targetList.getRealm().exec(new Runnable() {
public void run() {
ListDiff diff = Diffs.computeListDiff(Collections.EMPTY_LIST,
targetList);
doUpdate(targetList, (IObservableList) getModel(), diff,
targetToModel, true, true);
}
});
}
public void validateModelToTarget() {
// nothing for now
}
public void validateTargetToModel() {
// nothing for now
}
/*
* This method may be moved to UpdateListStrategy in the future if clients
* need more control over how the two lists are kept in sync.
*/
private void doUpdate(final IObservableList source,
final IObservableList destination, final ListDiff diff,
final UpdateListStrategy updateListStrategy,
final boolean explicit, final boolean clearDestination) {
final int policy = updateListStrategy.getUpdatePolicy();
if (policy != UpdateListStrategy.POLICY_NEVER) {
if (policy != UpdateListStrategy.POLICY_ON_REQUEST || explicit) {
destination.getRealm().exec(new Runnable() {
public void run() {
if (destination == getTarget()) {
updatingTarget = true;
} else {
updatingModel = true;
}
MultiStatus multiStatus = BindingStatus.ok();
try {
if (clearDestination) {
destination.clear();
}
ListDiffEntry[] diffEntries = diff.getDifferences();
for (int i = 0; i < diffEntries.length; i++) {
ListDiffEntry listDiffEntry = diffEntries[i];
if (listDiffEntry.isAddition()) {
IStatus setterStatus = updateListStrategy
.doAdd(
destination,
updateListStrategy
.convert(listDiffEntry
.getElement()),
listDiffEntry.getPosition());
mergeStatus(multiStatus, setterStatus);
// TODO - at this point, the two lists
// will be out of sync if an error occurred...
} else {
IStatus setterStatus = updateListStrategy
.doRemove(destination,
listDiffEntry.getPosition());
mergeStatus(multiStatus, setterStatus);
// TODO - at this point, the two lists
// will be out of sync if an error occurred...
}
}
} finally {
validationStatusObservable.setValue(multiStatus);
if (destination == getTarget()) {
updatingTarget = false;
} else {
updatingModel = false;
}
}
}
});
}
}
}
/**
* Merges the provided <code>newStatus</code> into the
* <code>multiStatus</code>.
*
* @param multiStatus
* @param newStatus
*/
/* package */void mergeStatus(MultiStatus multiStatus, IStatus newStatus) {
if (!newStatus.isOK()) {
multiStatus.add(newStatus);
}
}
public void dispose() {
if (targetChangeListener != null) {
((IObservableList)getTarget()).removeListChangeListener(targetChangeListener);
targetChangeListener = null;
}
if (modelChangeListener != null) {
((IObservableList)getModel()).removeListChangeListener(modelChangeListener);
modelChangeListener = null;
}
super.dispose();
}
}