| /******************************************************************************* |
| * Copyright (c) 2006, 2010 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 |
| * Matthew Hall - bugs 251884, 194734, 301774 |
| *******************************************************************************/ |
| |
| package org.eclipse.core.databinding.observable.map; |
| |
| import java.util.AbstractMap; |
| import java.util.AbstractSet; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.NoSuchElementException; |
| import java.util.Set; |
| import java.util.Map.Entry; |
| |
| import org.eclipse.core.databinding.observable.IDiff; |
| import org.eclipse.core.internal.databinding.observable.Util; |
| |
| /** |
| * @since 1.1 |
| * |
| */ |
| public abstract class MapDiff implements IDiff { |
| /** |
| * Returns true if the diff has no added, removed or changed entries. |
| * |
| * @return true if the diff has no added, removed or changed entries. |
| * @since 1.2 |
| */ |
| public boolean isEmpty() { |
| return getAddedKeys().isEmpty() && getRemovedKeys().isEmpty() |
| && getChangedKeys().isEmpty(); |
| } |
| |
| /** |
| * Applies the changes in this diff to the given map |
| * |
| * @param map |
| * the map to which the diff will be applied |
| * @since 1.2 |
| */ |
| public void applyTo(Map map) { |
| for (Iterator it = getAddedKeys().iterator(); it.hasNext();) { |
| Object key = it.next(); |
| map.put(key, getNewValue(key)); |
| } |
| for (Iterator it = getChangedKeys().iterator(); it.hasNext();) { |
| Object key = it.next(); |
| map.put(key, getNewValue(key)); |
| } |
| for (Iterator it = getRemovedKeys().iterator(); it.hasNext();) { |
| map.remove(it.next()); |
| } |
| } |
| |
| /** |
| * Returns a map showing what <code>map</code> would look like if this diff |
| * were applied to it. |
| * <p> |
| * <b>Note</b>: the returned map is only valid until structural changes are |
| * made to the passed-in map. |
| * |
| * @param map |
| * the map over which the diff will be simulated |
| * @return an unmodifiable map showing what <code>map</code> would look like |
| * if it were passed to the {@link #applyTo(Map)} method. |
| * @see #applyTo(Map) |
| * @since 1.3 |
| */ |
| public Map simulateOn(Map map) { |
| return new DeltaMap(map, this); |
| } |
| |
| private static class DeltaMap extends AbstractMap { |
| |
| private final Map map; |
| private final MapDiff diff; |
| |
| private Set entrySet; |
| |
| public DeltaMap(Map map, MapDiff diff) { |
| this.map = map; |
| this.diff = diff; |
| |
| } |
| |
| public void clear() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean containsKey(Object key) { |
| return diff.getAddedKeys().contains(key) |
| || (map.containsKey(key) && !diff.getRemovedKeys() |
| .contains(key)); |
| } |
| |
| public Set entrySet() { |
| if (entrySet == null) { |
| entrySet = new DeltaMapEntrySet(map, diff); |
| } |
| return entrySet; |
| } |
| |
| public Object get(Object key) { |
| if (diff.getAddedKeys().contains(key)) |
| return diff.getNewValue(key); |
| if (diff.getChangedKeys().contains(key)) |
| return diff.getNewValue(key); |
| if (diff.getRemovedKeys().contains(key)) |
| return null; |
| return map.get(key); |
| } |
| |
| public Object put(Object arg0, Object arg1) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void putAll(Map arg0) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public Object remove(Object key) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| } |
| |
| private static class DeltaMapEntrySet extends AbstractSet { |
| |
| private final Map map; |
| private final MapDiff diff; |
| |
| public DeltaMapEntrySet(Map map, MapDiff diff) { |
| this.map = map; |
| this.diff = diff; |
| } |
| |
| public Iterator iterator() { |
| return new Iterator() { |
| Iterator origEntries = map.entrySet().iterator(); |
| Iterator addedKeys = diff.getAddedKeys().iterator(); |
| |
| boolean haveNext = false; |
| Map.Entry next; |
| |
| public boolean hasNext() { |
| return findNext(); |
| } |
| |
| public Object next() { |
| if (!findNext()) |
| throw new NoSuchElementException(); |
| |
| Map.Entry myNext = next; |
| haveNext = false; |
| next = null; |
| return myNext; |
| } |
| |
| private boolean findNext() { |
| if (haveNext) |
| return true; |
| while (true) { |
| Object candidateKey; |
| Map.Entry candidateEntry; |
| if (origEntries.hasNext()) { |
| candidateEntry = (Map.Entry) origEntries.next(); |
| candidateKey = candidateEntry.getKey(); |
| |
| if (diff.getRemovedKeys().contains(candidateKey)) { |
| continue; |
| } else if (diff.getChangedKeys().contains( |
| candidateKey)) { |
| candidateEntry = new DeltaMapEntry( |
| candidateKey, diff); |
| } else { |
| candidateEntry = new MapEntryWrapper( |
| candidateEntry); |
| } |
| } else if (addedKeys.hasNext()) { |
| candidateKey = addedKeys.next(); |
| candidateEntry = new DeltaMapEntry(candidateKey, |
| diff); |
| } else { |
| return false; |
| } |
| |
| haveNext = true; |
| next = candidateEntry; |
| return true; |
| } |
| } |
| |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| }; |
| } |
| |
| public int size() { |
| return map.size() + diff.getAddedKeys().size() |
| - diff.getRemovedKeys().size(); |
| } |
| |
| } |
| |
| private abstract static class AbstractMapEntry implements Map.Entry { |
| public Object setValue(Object arg0) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean equals(Object obj) { |
| if (!(obj instanceof Map.Entry)) |
| return false; |
| Map.Entry that = (Map.Entry) obj; |
| return Util.equals(this.getKey(), that.getKey()) |
| && Util.equals(this.getValue(), that.getValue()); |
| } |
| |
| public int hashCode() { |
| Object key = getKey(); |
| Object value = getValue(); |
| return hash(key) ^ hash(value); |
| } |
| |
| private int hash(Object key) { |
| return key == null ? 0 : key.hashCode(); |
| } |
| } |
| |
| private static class MapEntryWrapper extends AbstractMapEntry { |
| private final Entry entry; |
| |
| public MapEntryWrapper(Map.Entry entry) { |
| this.entry = entry; |
| } |
| |
| public Object getKey() { |
| return entry.getKey(); |
| } |
| |
| public Object getValue() { |
| return entry.getValue(); |
| } |
| |
| } |
| |
| private static class DeltaMapEntry extends AbstractMapEntry { |
| private final Object key; |
| private final MapDiff diff; |
| |
| public DeltaMapEntry(Object key, MapDiff diff) { |
| this.key = key; |
| this.diff = diff; |
| } |
| |
| public Object getKey() { |
| return key; |
| } |
| |
| public Object getValue() { |
| return diff.getNewValue(key); |
| } |
| |
| } |
| |
| /** |
| * @return the set of keys which were added |
| */ |
| public abstract Set getAddedKeys(); |
| |
| /** |
| * @return the set of keys which were removed |
| */ |
| public abstract Set getRemovedKeys(); |
| |
| /** |
| * @return the set of keys for which the value has changed |
| */ |
| public abstract Set getChangedKeys(); |
| |
| /** |
| * Returns the old value for the given key, which must be an element of |
| * {@link #getRemovedKeys()} or {@link #getChangedKeys()}. |
| * |
| * @param key |
| * @return the old value for the given key. |
| */ |
| public abstract Object getOldValue(Object key); |
| |
| /** |
| * Returns the new value for the given key, which must be an element of |
| * {@link #getChangedKeys()} or {@link #getAddedKeys()}. |
| * |
| * @param key |
| * @return the new value for the given key. |
| */ |
| public abstract Object getNewValue(Object key); |
| } |