/*
* Copyright 2003-2004 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.util.Comparator;
import org.apache.commons.collections.Predicate;
import org.apache.commons.collections.SortedBag;
/**
* 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: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
*
* @author Stephen Colebourne
* @author Paul Jack
*/
public class PredicatedSortedBag
extends PredicatedBag implements SortedBag {
/** Serialization version */
private static final long serialVersionUID = 3448581314086406616L;
/**
* 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).
* <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.
*
* @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();
}
}