/*
* Copyright 2002-2005 The Apache Software Foundation
*
* Licensed 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.commons.collections.bag;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Collection;
import java.util.Comparator;
import java.util.SortedMap;
import java.util.TreeMap;
import org.apache.commons.collections.SortedBag;
/**
* Implements <code>SortedBag</code>, using a <code>TreeMap</code> to provide
* the data storage. This is the standard implementation of a sorted bag.
* <p>
* Order will be maintained among the bag members and can be viewed through the
* iterator.
* <p>
* A <code>Bag</code> stores each object in the collection together with a
* count of occurrences. Extra methods on the interface allow multiple copies
* of an object to be added or removed at once. It is important to read the
* interface javadoc carefully as several methods violate the
* <code>Collection</code> interface specification.
*
* @since Commons Collections 3.0 (previously in main package v2.0)
* @version $Revision: 348299 $ $Date: 2005-11-22 23:51:45 +0000 (Tue, 22 Nov 2005) $
*
* @author Chuck Burdick
* @author Stephen Colebourne
*/
public class TreeBag
extends AbstractMapBag implements SortedBag, Serializable {
/** Serial version lock */
private static final long serialVersionUID = -7740146511091606676L;
/**
* Constructs an empty <code>TreeBag</code>.
*/
public TreeBag() {
super(new TreeMap());
}
/**
* Constructs an empty bag that maintains order on its unique
* representative members according to the given {@link Comparator}.
*
* @param comparator the comparator to use
*/
public TreeBag(Comparator comparator) {
super(new TreeMap(comparator));
}
/**
* Constructs a <code>TreeBag</code> containing all the members of the
* specified collection.
*
* @param coll the collection to copy into the bag
*/
public TreeBag(Collection coll) {
this();
addAll(coll);
}
//-----------------------------------------------------------------------
public Object first() {
return ((SortedMap) getMap()).firstKey();
}
public Object last() {
return ((SortedMap) getMap()).lastKey();
}
public Comparator comparator() {
return ((SortedMap) getMap()).comparator();
}
//-----------------------------------------------------------------------
/**
* Write the bag out using a custom routine.
*/
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
out.writeObject(comparator());
super.doWriteObject(out);
}
/**
* Read the bag in using a custom routine.
*/
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
Comparator comp = (Comparator) in.readObject();
super.doReadObject(new TreeMap(comp), in);
}
}