| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.openjpa.util; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| |
| /** |
| * Default {@link CollectionChangeTracker}. |
| * |
| * @author Abe White |
| * @nojavadoc |
| */ |
| public class CollectionChangeTrackerImpl |
| extends AbstractChangeTracker |
| implements CollectionChangeTracker { |
| |
| private final Collection _coll; |
| private final boolean _dups; |
| private final boolean _order; |
| |
| /** |
| * Constructor. |
| * |
| * @param coll the collection to delegate to |
| * @param dups true if the collection allows duplicates, false otherwise |
| * @param order true if the collection is ordered, false otherwise |
| */ |
| public CollectionChangeTrackerImpl(Collection coll, boolean dups, |
| boolean order) { |
| _coll = coll; |
| _dups = dups; |
| _order = order; |
| } |
| |
| /** |
| * Whether the underlying collection allows duplicates. |
| */ |
| public boolean allowsDuplicates() { |
| return _dups; |
| } |
| |
| /** |
| * Whether the underlying collection is ordered. |
| */ |
| public boolean isOrdered() { |
| return _order; |
| } |
| |
| public void added(Object elem) { |
| super.added(elem); |
| } |
| |
| public void removed(Object elem) { |
| super.removed(elem); |
| } |
| |
| protected int initialSequence() { |
| if (_order) |
| return _coll.size(); |
| return super.initialSequence(); |
| } |
| |
| protected void add(Object elem) { |
| if (rem == null || !rem.remove(elem)) { |
| // after a point it's inefficient to keep tracking |
| if (getAutoOff() |
| && getAdded().size() + getRemoved().size() >= _coll.size()) |
| stopTracking(); |
| else { |
| if (add == null) { |
| if (_dups || _order) |
| add = new ArrayList(); |
| else |
| add = newSet(); |
| } |
| add.add(elem); |
| } |
| } else if (_order) |
| stopTracking(); |
| else { |
| if (change == null) |
| change = newSet(); |
| change.add(elem); |
| } |
| } |
| |
| protected void remove(Object elem) { |
| // if the collection contains multiple copies of the elem, we can't |
| // use change tracking because some back-ends can't just delete a |
| // single copy of a elem |
| if (_dups && getAutoOff() && _coll.contains(elem)) |
| stopTracking(); |
| else if (add == null || !add.remove(elem)) { |
| // after a point it's inefficient to keep tracking |
| if (getAutoOff() |
| && getRemoved().size() + getAdded().size() >= _coll.size()) |
| stopTracking(); |
| else { |
| if (rem == null) |
| rem = newSet(); |
| rem.add(elem); |
| } |
| } |
| } |
| |
| protected void change(Object elem) { |
| throw new InternalException(); |
| } |
| } |