bundles/common/org.eclipse.apogy.common.emf.databinding/src/org/eclipse/apogy/common/emf/databinding/EMFReferenceIObervableValue.java

/*******************************************************************************
 * Copyright (c) 2018 Agence spatiale canadienne / Canadian Space Agency
 * 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:
<<<<<<< HEAD
 *     Pierre Allard - initial API and implementation
 *     Regent L'Archeveque
 * 
=======
 *     Pierre Allard, 
 *     Regent L'Archeveque - initial API and implementation
 *     
>>>>>>> refs/heads/eclipse_pa
 * SPDX-License-Identifier: EPL-1.0
 *     
 *******************************************************************************/
package org.eclipse.apogy.common.emf.databinding;

import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.value.ValueDiff;
import org.eclipse.emf.common.notify.Adapter;
import org.eclipse.emf.common.notify.Notification;
import org.eclipse.emf.common.notify.impl.AdapterImpl;
import org.eclipse.emf.databinding.EObjectObservableValue;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.emf.ecore.util.ExtendedMetaData;

public class EMFReferenceIObervableValue extends EObjectObservableValue {
	protected Adapter valueInternalAdapter = null;
	protected EObject featurevalue;

	public EMFReferenceIObervableValue(EObject eObject, EStructuralFeature eStructuralFeature) {
		super(eObject, eStructuralFeature);
		this.featurevalue = (EObject) (ExtendedMetaData.INSTANCE.getAffiliation(eObject.eClass(),
				eStructuralFeature) == null ? null : eObject.eGet(eStructuralFeature));

		// Register interval value listener to new value if applicable.
		if (this.featurevalue != null) {
			this.featurevalue.eAdapters().add(getValueInternalAdapter());
		}
	}

	@Override
	protected Object doGetValue() {
		return this.featurevalue;
	}

	@Override
	protected void firstListenerAdded() {
		this.listener = new AdapterImpl() {
			@Override
			public void notifyChanged(Notification notification) {
				if (EMFReferenceIObervableValue.this.eStructuralFeature == notification.getFeature()
						&& !notification.isTouch()) {
					// Unregister interval value listener from old value if applicable.
					if (notification.getOldValue() instanceof EObject) {
						((EObject) notification.getOldValue()).eAdapters().remove(getValueInternalAdapter());
					}

					// Register interval value listener to new value if applicable.
					if (notification.getNewValue() instanceof EObject) {
						((EObject) notification.getNewValue()).eAdapters().add(getValueInternalAdapter());
						EMFReferenceIObervableValue.this.featurevalue = ((EObject) notification.getNewValue());
					} else {
						EMFReferenceIObervableValue.this.featurevalue = null;
					}

					final ValueDiff<Object> diff = Diffs.createValueDiff(notification.getOldValue(),
							notification.getNewValue());
					getRealm().exec(new Runnable() {
						@Override
						public void run() {
							fireValueChange(diff);
						}
					});
				}
			}
		};
		this.eObject.eAdapters().add(this.listener);
	}

	@Override
	protected void lastListenerRemoved() {
		// Removes valueInternalAdapter if applicable.
		if (this.featurevalue != null)
			this.featurevalue.eAdapters().remove(getValueInternalAdapter());
		super.lastListenerRemoved();
	}

	protected Adapter getValueInternalAdapter() {
		if (this.valueInternalAdapter == null) {
			this.valueInternalAdapter = new AdapterImpl() {
				@Override
				public void notifyChanged(Notification msg) {
					// Forces update
					Object obj = msg.getNotifier();
					if (obj instanceof EObject) {
						EObject oldvalue = (EObject) obj;
						EMFReferenceIObervableValue.this.featurevalue = EcoreUtil.copy(oldvalue);
						final ValueDiff diff = Diffs.createValueDiff(null,
								EMFReferenceIObervableValue.this.featurevalue);

						getRealm().exec(new Runnable() {
							@Override
							public void run() {
								fireValueChange(diff);
							}
						});
					}
				};
			};
		}

		return this.valueInternalAdapter;
	}
}