/*
 *  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.commons.collections.bag;

import java.util.Comparator;

import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.SortedBag;

Decorates another SortedBag to validate that additions
match a specified predicate.

This bag exists to provide validation for the decorated bag.
It is normally created to decorate an empty bag.
If an object cannot be added to the bag, an IllegalArgumentException is thrown.

One usage would be to ensure that no null entries are added to the bag.
SortedBag bag = PredicatedSortedBag.decorate(new TreeBag(), NotNullPredicate.INSTANCE);

This class is Serializable from Commons Collections 3.1.
Author:
Stephen Colebourne, Paul Jack
Since:
Commons Collections 3.0
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $/**
 * Decorates another <code>SortedBag</code> to validate that additions
 * match a specified predicate.
 * <p>
 * This bag exists to provide validation for the decorated bag.
 * It is normally created to decorate an empty bag.
 * If an object cannot be added to the bag, an IllegalArgumentException is thrown.
 * <p>
 * One usage would be to ensure that no null entries are added to the bag.
 * <pre>SortedBag bag = PredicatedSortedBag.decorate(new TreeBag(), NotNullPredicate.INSTANCE);</pre>
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 *
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
 * 
 * @author Stephen Colebourne
 * @author Paul Jack
 */
public class PredicatedSortedBag
        extends PredicatedBag implements SortedBag {

    
Serialization version /** Serialization version */
    private static final long serialVersionUID = 3448581314086406616L;

    
Factory method to create a predicated (validating) bag.

If there are any elements already in the bag being decorated, they
are validated.
Params:
bag –  the bag to decorate, must not be null
predicate –  the predicate to use for validation, must not be null
Throws:
IllegalArgumentException – if bag or predicate is null
IllegalArgumentException – if the bag contains invalid elements
Returns:
a new predicated SortedBag/**
     * Factory method to create a predicated (validating) bag.
     * <p>
     * If there are any elements already in the bag being decorated, they
     * are validated.
     * 
     * @param bag  the bag to decorate, must not be null
     * @param predicate  the predicate to use for validation, must not be null
     * @return a new predicated SortedBag
     * @throws IllegalArgumentException if bag or predicate is null
     * @throws IllegalArgumentException if the bag contains invalid elements
     */
    public static SortedBag decorate(SortedBag bag, Predicate predicate) {
        return new PredicatedSortedBag(bag, predicate);
    }

    //-----------------------------------------------------------------------
    
Constructor that wraps (not copies).

If there are any elements already in the bag being decorated, they
are validated.
Params:
bag –  the bag to decorate, must not be null
predicate –  the predicate to use for validation, must not be null
Throws:
IllegalArgumentException – if bag or predicate is null
IllegalArgumentException – if the bag contains invalid elements/**
     * Constructor that wraps (not copies).
     * <p>
     * If there are any elements already in the bag being decorated, they
     * are validated.
     * 
     * @param bag  the bag to decorate, must not be null
     * @param predicate  the predicate to use for validation, must not be null
     * @throws IllegalArgumentException if bag or predicate is null
     * @throws IllegalArgumentException if the bag contains invalid elements
     */
    protected PredicatedSortedBag(SortedBag bag, Predicate predicate) {
        super(bag, predicate);
    }

    
Gets the decorated sorted bag.
Returns:
the decorated bag/**
     * Gets the decorated sorted bag.
     * 
     * @return the decorated bag
     */
    protected SortedBag getSortedBag() {
        return (SortedBag) getCollection();
    }
    
    //-----------------------------------------------------------------------
    public Object first() {
        return getSortedBag().first();
    }

    public Object last() {
        return getSortedBag().last();
    }

    public Comparator comparator() {
        return getSortedBag().comparator();
    }

}