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/*******************************************************************************
* Copyright (c) 2007, 2017 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
* Matthew Hall - bugs 262221, 271148, 280341, 278550
******************************************************************************/
package org.eclipse.core.databinding;
import java.util.Collections;
import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.ObservableTracker;
import org.eclipse.core.databinding.observable.list.IListChangeListener;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.ListDiff;
import org.eclipse.core.databinding.observable.list.ListDiffVisitor;
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;
/**
* @param <T>
* the type of the elements in the list on the target side
* @param <M>
* the type of the elements in the list on the model side
* @since 1.0
*
*/
public class ListBinding<M, T> extends Binding {
private UpdateListStrategy<? super T, ? extends M> targetToModel;
private UpdateListStrategy<? super M, ? extends T> modelToTarget;
private IObservableValue<IStatus> validationStatusObservable;
private IObservableList<T> target;
private IObservableList<M> model;
private boolean updatingTarget;
private boolean updatingModel;
private IListChangeListener<T> targetChangeListener = event -> {
if (!updatingTarget) {
doUpdate(target, model, event.diff, targetToModel, false, false);
}
};
private IListChangeListener<M> modelChangeListener = event -> {
if (!updatingModel) {
doUpdate(model, target, event.diff, modelToTarget, false, false);
}
};
/**
* @param target
* @param model
* @param modelToTargetStrategy
* @param targetToModelStrategy
*/
public ListBinding(IObservableList<T> target, IObservableList<M> model,
UpdateListStrategy<? super T, ? extends M> targetToModelStrategy,
UpdateListStrategy<? super M, ? extends T> modelToTargetStrategy) {
super(target, model);
this.target = target;
this.model = model;
this.targetToModel = targetToModelStrategy;
this.modelToTarget = modelToTargetStrategy;
}
@Override
public IObservableValue<IStatus> getValidationStatus() {
return validationStatusObservable;
}
@Override
protected void preInit() {
ObservableTracker.setIgnore(true);
try {
validationStatusObservable = new WritableValue<>(
context.getValidationRealm(), Status.OK_STATUS,
IStatus.class);
} finally {
ObservableTracker.setIgnore(false);
}
}
@Override
protected void postInit() {
if (modelToTarget.getUpdatePolicy() == UpdateListStrategy.POLICY_UPDATE) {
model.getRealm().exec(() -> {
model.addListChangeListener(modelChangeListener);
updateModelToTarget();
});
} else {
modelChangeListener = null;
}
if (targetToModel.getUpdatePolicy() == UpdateListStrategy.POLICY_UPDATE) {
target.getRealm().exec(() -> {
target.addListChangeListener(targetChangeListener);
if (modelToTarget.getUpdatePolicy() == UpdateListStrategy.POLICY_NEVER) {
// we have to sync from target to model, if the other
// way round (model to target) is forbidden
// (POLICY_NEVER)
updateTargetToModel();
} else {
validateTargetToModel();
}
});
} else {
targetChangeListener = null;
}
}
@Override
public void updateModelToTarget() {
model.getRealm().exec(() -> {
ListDiff<M> diff = Diffs.computeListDiff(Collections.emptyList(), model);
doUpdate(model, target, diff, modelToTarget, true, true);
});
}
@Override
public void updateTargetToModel() {
target.getRealm().exec(() -> {
ListDiff<T> diff = Diffs.computeListDiff(Collections.emptyList(), target);
doUpdate(target, model, diff, targetToModel, true, true);
});
}
@Override
public void validateModelToTarget() {
// nothing for now
}
@Override
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 <S, D1, D2 extends D1> void doUpdate(final IObservableList<S> source,
final IObservableList<D1> destination, final ListDiff<? extends S> diff,
final UpdateListStrategy<? super S, D2> updateListStrategy,
final boolean explicit, final boolean clearDestination) {
final int policy = updateListStrategy.getUpdatePolicy();
if (policy != UpdateListStrategy.POLICY_NEVER) {
if (policy != UpdateListStrategy.POLICY_ON_REQUEST || explicit) {
if (!destination.getRealm().isCurrent()) {
/*
* If the destination is different from the source realm, we have to avoid lazy
* diff calculation.
*/
diff.getDifferences();
}
destination.getRealm().exec(() -> {
if (destination == target) {
updatingTarget = true;
} else {
updatingModel = true;
}
final MultiStatus multiStatus = BindingStatus.ok();
try {
if (clearDestination) {
destination.clear();
}
diff.accept(new ListDiffVisitor<S>() {
boolean useMoveAndReplace = updateListStrategy.useMoveAndReplace();
@Override
public void handleAdd(int index, S element) {
IStatus setterStatus = updateListStrategy.doAdd(destination,
updateListStrategy.convert(element), index);
mergeStatus(multiStatus, setterStatus);
}
@Override
public void handleRemove(int index, S element) {
IStatus setterStatus = updateListStrategy.doRemove(destination, index);
mergeStatus(multiStatus, setterStatus);
}
@Override
public void handleMove(int oldIndex, int newIndex, S element) {
if (useMoveAndReplace) {
IStatus setterStatus = updateListStrategy
.doMove(destination, oldIndex, newIndex);
mergeStatus(multiStatus, setterStatus);
} else {
super.handleMove(oldIndex, newIndex, element);
}
}
@Override
public void handleReplace(int index, S oldElement, S newElement) {
if (useMoveAndReplace) {
IStatus setterStatus = updateListStrategy.doReplace(
destination, index, updateListStrategy.convert(newElement));
mergeStatus(multiStatus, setterStatus);
} else {
super.handleReplace(index, oldElement, newElement);
}
}
});
// TODO - at this point, the two lists will be out
// of sync if an error occurred...
} finally {
setValidationStatus(multiStatus);
if (destination == target) {
updatingTarget = false;
} else {
updatingModel = false;
}
}
});
}
}
}
private void setValidationStatus(final IStatus status) {
validationStatusObservable.getRealm().exec(() -> validationStatusObservable.setValue(status));
}
/**
* 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);
}
}
@Override
public void dispose() {
if (targetChangeListener != null) {
target.removeListChangeListener(targetChangeListener);
targetChangeListener = null;
}
if (modelChangeListener != null) {
model.removeListChangeListener(modelChangeListener);
modelChangeListener = null;
}
super.dispose();
}
}
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