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/*******************************************************************************
* Copyright (c) 2008, 2017 Matthew Hall 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:
* Matthew Hall - initial API and implementation (bug 124684)
* IBM Corporation - through ListBinding.java
* Matthew Hall - bugs 271148, 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.set.IObservableSet;
import org.eclipse.core.databinding.observable.set.ISetChangeListener;
import org.eclipse.core.databinding.observable.set.SetDiff;
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 set on the target side
* @param <M>
* the type of the elements in the set on the model side
* @since 1.1
*
*/
public class SetBinding<M, T> extends Binding {
private UpdateSetStrategy<? super T, ? extends M> targetToModel;
private UpdateSetStrategy<? super M, ? extends T> modelToTarget;
private IObservableValue<IStatus> validationStatusObservable;
private IObservableSet<T> target;
private IObservableSet<M> model;
private boolean updatingTarget;
private boolean updatingModel;
private ISetChangeListener<T> targetChangeListener = event -> {
if (!updatingTarget) {
doUpdate(target, model, event.diff, targetToModel, false, false);
}
};
private ISetChangeListener<M> modelChangeListener = event -> {
if (!updatingModel) {
doUpdate(model, target, event.diff, modelToTarget, false, false);
}
};
/**
* @param target
* @param model
* @param modelToTargetStrategy
* @param targetToModelStrategy
*/
public SetBinding(IObservableSet<T> target, IObservableSet<M> model,
UpdateSetStrategy<? super T, ? extends M> targetToModelStrategy,
UpdateSetStrategy<? 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() == UpdateSetStrategy.POLICY_UPDATE) {
model.getRealm().exec(() -> {
model.addSetChangeListener(modelChangeListener);
updateModelToTarget();
});
} else {
modelChangeListener = null;
}
if (targetToModel.getUpdatePolicy() == UpdateSetStrategy.POLICY_UPDATE) {
target.getRealm().exec(() -> {
target.addSetChangeListener(targetChangeListener);
if (modelToTarget.getUpdatePolicy() == UpdateSetStrategy.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(() -> {
SetDiff<M> diff = Diffs.computeSetDiff(Collections.emptySet(), model);
doUpdate(model, target, diff, modelToTarget, true, true);
});
}
@Override
public void updateTargetToModel() {
target.getRealm().exec(() -> {
SetDiff<T> diff = Diffs.computeSetDiff(Collections.emptySet(), 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 UpdateSetStrategy in the future if clients
* need more control over how the two sets are kept in sync.
*/
private <S, D1, D2 extends D1> void doUpdate(final IObservableSet<S> source, final IObservableSet<D1> destination,
final SetDiff<? extends S> diff, final UpdateSetStrategy<? super S, D2> updateSetStrategy,
final boolean explicit, final boolean clearDestination) {
final int policy = updateSetStrategy.getUpdatePolicy();
if (policy == UpdateSetStrategy.POLICY_NEVER)
return;
if (policy == UpdateSetStrategy.POLICY_ON_REQUEST && !explicit)
return;
if (!destination.getRealm().isCurrent()) {
/*
* If the destination is different from the source realm, we have to avoid lazy
* diff calculation.
*/
diff.getAdditions();
diff.getRemovals();
}
destination.getRealm().exec(() -> {
if (destination == target) {
updatingTarget = true;
} else {
updatingModel = true;
}
MultiStatus multiStatus = BindingStatus.ok();
try {
if (clearDestination) {
destination.clear();
}
for (S element : diff.getRemovals()) {
IStatus setterStatus1 = updateSetStrategy.doRemove(destination, updateSetStrategy.convert(element));
mergeStatus(multiStatus, setterStatus1);
// TODO - at this point, the two sets
// will be out of sync if an error
// occurred...
}
for (S element : diff.getAdditions()) {
IStatus setterStatus2 = updateSetStrategy.doAdd(destination, updateSetStrategy.convert(element));
mergeStatus(multiStatus, setterStatus2);
// TODO - at this point, the two sets
// 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.removeSetChangeListener(targetChangeListener);
targetChangeListener = null;
}
if (modelChangeListener != null) {
model.removeSetChangeListener(modelChangeListener);
modelChangeListener = null;
}
super.dispose();
}
}
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