| /******************************************************************************* |
| * Copyright (c) 2006, 2007 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.core.databinding.observable.map; |
| |
| import java.util.AbstractSet; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.eclipse.core.databinding.observable.Diffs; |
| import org.eclipse.core.databinding.observable.set.IObservableSet; |
| import org.eclipse.core.databinding.observable.set.ISetChangeListener; |
| import org.eclipse.core.databinding.observable.set.SetChangeEvent; |
| |
| /** |
| * Maps objects to one of their attributes. Tracks changes to the underlying |
| * observable set of objects (keys), as well as changes to attribute values. |
| */ |
| public abstract class ComputedObservableMap extends AbstractObservableMap { |
| |
| private final IObservableSet keySet; |
| |
| private ISetChangeListener setChangeListener = new ISetChangeListener() { |
| public void handleSetChange(SetChangeEvent event) { |
| Set addedKeys = new HashSet(event.diff.getAdditions()); |
| Set removedKeys = new HashSet(event.diff.getRemovals()); |
| Map oldValues = new HashMap(); |
| Map newValues = new HashMap(); |
| for (Iterator it = removedKeys.iterator(); it.hasNext();) { |
| Object removedKey = it.next(); |
| Object oldValue = doGet(removedKey); |
| unhookListener(removedKey); |
| if (oldValue != null) { |
| oldValues.put(removedKey, oldValue); |
| } |
| } |
| for (Iterator it = addedKeys.iterator(); it.hasNext();) { |
| Object addedKey = it.next(); |
| hookListener(addedKey); |
| Object newValue = doGet(addedKey); |
| newValues.put(addedKey, newValue); |
| } |
| fireMapChange(Diffs.createMapDiff(addedKeys, removedKeys, |
| Collections.EMPTY_SET, oldValues, newValues)); |
| } |
| }; |
| |
| private Set entrySet = new EntrySet(); |
| |
| private class EntrySet extends AbstractSet { |
| |
| public Iterator iterator() { |
| final Iterator keyIterator = keySet.iterator(); |
| return new Iterator() { |
| |
| public boolean hasNext() { |
| return keyIterator.hasNext(); |
| } |
| |
| public Object next() { |
| final Object key = keyIterator.next(); |
| return new Map.Entry() { |
| |
| public Object getKey() { |
| return key; |
| } |
| |
| public Object getValue() { |
| return get(getKey()); |
| } |
| |
| public Object setValue(Object value) { |
| return put(getKey(), value); |
| } |
| }; |
| } |
| |
| public void remove() { |
| keyIterator.remove(); |
| } |
| }; |
| } |
| |
| public int size() { |
| return keySet.size(); |
| } |
| |
| } |
| |
| /** |
| * @param keySet |
| */ |
| public ComputedObservableMap(IObservableSet keySet) { |
| super(keySet.getRealm()); |
| this.keySet = keySet; |
| this.keySet.addSetChangeListener(setChangeListener); |
| } |
| |
| protected void init() { |
| for (Iterator it = this.keySet.iterator(); it.hasNext();) { |
| Object key = it.next(); |
| hookListener(key); |
| } |
| } |
| |
| protected final void fireSingleChange(Object key, Object oldValue, |
| Object newValue) { |
| fireMapChange(Diffs.createMapDiffSingleChange(key, oldValue, newValue)); |
| } |
| |
| public Set entrySet() { |
| return entrySet; |
| } |
| |
| public Set keySet() { |
| return keySet; |
| } |
| |
| final public Object get(Object key) { |
| return doGet(key); |
| } |
| |
| final public Object put(Object key, Object value) { |
| return doPut(key, value); |
| } |
| |
| /** |
| * @param removedKey |
| */ |
| protected abstract void unhookListener(Object removedKey); |
| |
| /** |
| * @param addedKey |
| */ |
| protected abstract void hookListener(Object addedKey); |
| |
| /** |
| * @param key |
| * @return the value for the given key |
| */ |
| protected abstract Object doGet(Object key); |
| |
| /** |
| * @param key |
| * @param value |
| * @return the old value for the given key |
| */ |
| protected abstract Object doPut(Object key, Object value); |
| } |