/*******************************************************************************
* Copyright (c) 2001, 2005 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.jem.internal.instantiation.base;
/*
*/
import java.util.Iterator;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
/**
* Implementers of this interface (an EMF EObject subclass) provide a visiter
* capability to the set features on the EObject. This way only the set features
* are presented to the visitor. This can save a lot of time.
*
* @since 1.1.0
*/
public interface FeatureValueProvider {
/**
* A helper class for FeatureValueProvider.
*
* @see FeatureValueProviderHelper#visitSetFeatures(EObject, Visitor)
*
* @since 1.1.0
*/
public static class FeatureValueProviderHelper {
/**
* A helper to handle where the object may or may not be
* implement FeatureValueProvider. This way it can be a
* common access to do it.
*
* @param eobject
* @param visitor
* @return
*
* @since 1.1.0
*/
public static Object visitSetFeatures(EObject eobject, Visitor visitor) {
if (eobject instanceof FeatureValueProvider)
return ((FeatureValueProvider)eobject).visitSetFeatures(visitor);
else {
// Not a FeatureValueProvider, so do normal.
Iterator features = eobject.eClass().getEAllStructuralFeatures().iterator();
while(features.hasNext()){
EStructuralFeature sf = (EStructuralFeature)features.next();
if(eobject.eIsSet(sf)){
Object result = visitor.isSet(sf, eobject.eGet(sf));
if (result != null)
return result;
}
}
return null;
}
}
/**
* Answers whether any feature is set or not.
* <p>
* <b>Note:</b> This SHOULD NOT be used as a test before deciding whether to do visitSetFeatures or not. It is more efficient to just call
* visitSetFeatures. It should be used only to see if any features are set.
*
* @param eobject
* @return
*
* @since 1.1.0
*/
public static boolean isAnyFeatureSet(EObject eobject) {
if (eobject instanceof FeatureValueProvider)
return ((FeatureValueProvider)eobject).isAnyFeatureSet();
else {
// Not a FeatureValueProvider, so do normal.
Iterator features = eobject.eClass().getEAllStructuralFeatures().iterator();
while(features.hasNext()){
EStructuralFeature sf = (EStructuralFeature)features.next();
if(eobject.eIsSet(sf)){
return true;
}
}
return false;
}
}
private FeatureValueProviderHelper() {
}
}
/**
* The interface for the visiter callback.
*
* @since 1.1.0
*/
public interface Visitor{
/**
* Called for each set feature on the FeatureValueProvider.
*
* @param feature
* @param value
* @return <code>null</code> to continue to next setting, or a value to stop visiting and return that value be the real exception.
* @since 1.1.0
*/
Object isSet(EStructuralFeature feature, Object value);
}
/**
* Visit the set features.
* @param aVisitor
* @param <code>null</code> if all settings visited, or the value returned from the visit (isSet) that returned a non-nullSe.
* @since 1.1.0
*/
public Object visitSetFeatures(Visitor aVisitor);
/**
* Answers whether any feature is set or not.
* <p>
* <b>Note:</b> This SHOULD NOT be used as a test before deciding whether to do visitSetFeatures or not. It is
* more efficient to just call visitSetFeatures. It should be used only to see if any features are set.
*
* @return <code>true</code> if any features are set.
*
* @since 1.1.0
*/
public boolean isAnyFeatureSet();
}