| /* |
| * Copyright (c) 2008, 2011, 2012 Eike Stepper (Berlin, Germany) 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: |
| * Eike Stepper - initial API and implementation |
| */ |
| package org.eclipse.net4j.util.registry; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * Implementation note: AbstractDelegatingRegistry does not preserve the "modifyable view" contract of |
| * {@link Map#entrySet()} as well as of {@link Map#keySet()}, i.e. they are disconnected sets and modifications applied |
| * to them are not applied to their underlying AbstractDelegatingRegistry. |
| * <p> |
| * |
| * @author Eike Stepper |
| */ |
| public abstract class DelegatingRegistry<K, V> extends Registry<K, V> |
| { |
| private IRegistry<K, V> delegate; |
| |
| public DelegatingRegistry(IRegistry<K, V> delegate) |
| { |
| this.delegate = delegate; |
| } |
| |
| public DelegatingRegistry(IRegistry<K, V> delegate, boolean autoCommit) |
| { |
| super(autoCommit); |
| this.delegate = delegate; |
| } |
| |
| @Override |
| public V get(Object key) |
| { |
| V result = getMap().get(key); |
| if (result == null && delegate != null) |
| { |
| result = delegate.get(key); |
| } |
| |
| return result; |
| } |
| |
| @Override |
| public Set<Entry<K, V>> entrySet() |
| { |
| return mergedEntrySet(); |
| } |
| |
| @Override |
| public Set<K> keySet() |
| { |
| return mergedKeySet(); |
| } |
| |
| @Override |
| public Collection<V> values() |
| { |
| return mergedValues(); |
| } |
| |
| @Override |
| protected V register(K key, V value) |
| { |
| V delegated = delegate != null ? delegate.get(key) : null; |
| V old = getMap().put(key, value); |
| if (old == null) |
| { |
| if (delegated != null) |
| { |
| // Unhidden delegated element now becomes hidden |
| getTransaction().rememberDeregistered(key, delegated); |
| } |
| |
| getTransaction().rememberRegistered(key, value); |
| return delegated; |
| } |
| |
| getTransaction().rememberDeregistered(key, old); |
| getTransaction().rememberRegistered(key, value); |
| return old; |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| protected V deregister(Object key) |
| { |
| V delegated = delegate != null ? delegate.get(key) : null; |
| V old = getMap().remove(key); |
| if (old != null) |
| { |
| getTransaction().rememberDeregistered((K)key, old); |
| if (delegated != null) |
| { |
| // Hidden delegated element now becomes unhidden |
| getTransaction().rememberRegistered((K)key, delegated); |
| } |
| } |
| |
| return old; |
| } |
| |
| protected Set<Entry<K, V>> mergedEntrySet() |
| { |
| final Map<K, V> merged = new HashMap<K, V>(); |
| if (delegate != null) |
| { |
| merged.putAll(delegate); |
| } |
| |
| merged.putAll(getMap()); |
| return merged.entrySet(); |
| } |
| |
| protected Set<K> mergedKeySet() |
| { |
| final Set<K> merged = new HashSet<K>(); |
| if (delegate != null) |
| { |
| merged.addAll(delegate.keySet()); |
| } |
| |
| merged.addAll(getMap().keySet()); |
| return merged; |
| } |
| |
| protected Collection<V> mergedValues() |
| { |
| final List<V> result = new ArrayList<V>(); |
| for (K key : keySet()) |
| { |
| result.add(get(key)); |
| } |
| |
| return result; |
| } |
| } |