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/*******************************************************************************
* Copyright (c) 2007, 2008 Oracle. 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:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.utility.internal.model.value;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import org.eclipse.jpt.utility.internal.CollectionTools;
import org.eclipse.jpt.utility.internal.iterators.ReadOnlyListIterator;
import org.eclipse.jpt.utility.model.Model;
import org.eclipse.jpt.utility.model.event.StateChangeEvent;
import org.eclipse.jpt.utility.model.listener.ChangeListener;
import org.eclipse.jpt.utility.model.listener.ListChangeListener;
import org.eclipse.jpt.utility.model.listener.StateChangeListener;
import org.eclipse.jpt.utility.model.value.ListValueModel;
import org.eclipse.jpt.utility.model.value.PropertyValueModel;
/**
* This extension of AspectAdapter provides ListChange support
* by adapting a subject's state change events to a minimum set
* of list change events.
*/
public abstract class ListCurator<S extends Model, E>
extends AspectAdapter<S>
implements ListValueModel<E>
{
/** How the list looked before the last state change */
private final ArrayList<E> record;
/** A listener that listens for the subject's state to change */
private final StateChangeListener stateChangeListener;
// ********** constructors **********
/**
* Construct a Curator for the specified subject.
*/
protected ListCurator(S subject) {
this(new StaticPropertyValueModel<S>(subject));
}
/**
* Construct a curator for the specified subject holder.
* The subject holder cannot be null.
*/
protected ListCurator(PropertyValueModel<? extends S> subjectHolder) {
super(subjectHolder);
this.record = new ArrayList<E>();
this.stateChangeListener = this.buildStateChangeListener();
}
// ********** initialization **********
/**
* The subject's state has changed, do inventory and report to listeners.
*/
protected StateChangeListener buildStateChangeListener() {
return new StateChangeListener() {
public void stateChanged(StateChangeEvent event) {
ListCurator.this.submitInventoryReport();
}
@Override
public String toString() {
return "state change listener";
}
};
}
// ********** ListValueModel implementation **********
public Iterator<E> iterator() {
return this.listIterator();
}
public ListIterator<E> listIterator() {
return new ReadOnlyListIterator<E>(this.record);
}
/**
* Return the item at the specified index of the subject's list aspect.
*/
public E get(int index) {
return this.record.get(index);
}
/**
* Return the size of the subject's list aspect.
*/
public int size() {
return this.record.size();
}
/**
* Return an array manifestation of the subject's list aspect.
*/
public Object[] toArray() {
return this.record.toArray();
}
// ********** AspectAdapter implementation **********
@Override
protected Object getValue() {
return this.iterator();
}
@Override
protected Class<? extends ChangeListener> getListenerClass() {
return ListChangeListener.class;
}
@Override
protected String getListenerAspectName() {
return LIST_VALUES;
}
@Override
protected boolean hasListeners() {
return this.hasAnyListChangeListeners(LIST_VALUES);
}
/**
* The aspect has changed, notify listeners appropriately.
*/
@Override
protected void fireAspectChange(Object oldValue, Object newValue) {
this.fireListChanged(LIST_VALUES);
}
/**
* The subject is not null - add our listener.
*/
@Override
protected void engageSubject_() {
((Model) this.subject).addStateChangeListener(this.stateChangeListener);
// synch our list *after* we start listening to the subject,
// since its value might change when a listener is added
CollectionTools.addAll(this.record, this.iteratorForRecord());
}
/**
* The subject is not null - remove our listener.
*/
@Override
protected void disengageSubject_() {
((Model) this.subject).removeStateChangeListener(this.stateChangeListener);
// clear out the list when we are not listening to the subject
this.record.clear();
}
// ********** ListCurator protocol **********
/**
* This is intended to be different from #ListValueModel.iterator().
* It is intended to be used only when the subject changes or the
* subject's "state" changes (as signified by a state change event).
*/
protected abstract Iterator<E> iteratorForRecord();
// ********** behavior **********
void submitInventoryReport() {
List<E> newRecord = CollectionTools.list(this.iteratorForRecord());
int recordIndex = 0;
// add items from the new record
for (E newItem : newRecord) {
this.inventoryNewItem(recordIndex, newItem);
recordIndex++;
}
// clean out items that are no longer in the new record
for (recordIndex = 0; recordIndex < this.record.size(); ) {
E item = this.record.get(recordIndex);
if (newRecord.contains(item)) {
recordIndex++;
} else {
this.removeItemFromInventory(recordIndex, item);
}
}
}
private void inventoryNewItem(int recordIndex, E newItem) {
List<E> rec = new ArrayList<E>(this.record);
if ((recordIndex < rec.size()) && rec.get(recordIndex).equals(newItem)) {
return;
}
if (rec.contains(newItem)) {
this.removeItemFromInventory(recordIndex, rec.get(recordIndex));
this.inventoryNewItem(recordIndex, newItem);
} else {
this.addItemToInventory(recordIndex, newItem);
}
}
private void addItemToInventory(int index, E item) {
this.addItemToList(index, item, this.record, LIST_VALUES);
}
private void removeItemFromInventory(int index, E item) {
this.removeItemFromList(index, this.record, LIST_VALUES);
}
}
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