001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.collections4.bag; 018 019import java.util.Comparator; 020 021import org.apache.commons.collections4.Predicate; 022import org.apache.commons.collections4.SortedBag; 023 024/** 025 * Decorates another {@link SortedBag} to validate that additions 026 * match a specified predicate. 027 * <p> 028 * This bag exists to provide validation for the decorated bag. 029 * It is normally created to decorate an empty bag. 030 * If an object cannot be added to the bag, an {@link IllegalArgumentException} is thrown. 031 * <p> 032 * One usage would be to ensure that no null entries are added to the bag. 033 * <pre>SortedBag bag = PredicatedSortedBag.decorate(new TreeBag(), NotNullPredicate.INSTANCE);</pre> 034 * <p> 035 * This class is Serializable from Commons Collections 3.1. 036 * 037 * @since 3.0 038 * @version $Id: PredicatedSortedBag.html 972421 2015-11-14 20:00:04Z tn $ 039 */ 040public class PredicatedSortedBag<E> extends PredicatedBag<E> implements SortedBag<E> { 041 042 /** Serialization version */ 043 private static final long serialVersionUID = 3448581314086406616L; 044 045 /** 046 * Factory method to create a predicated (validating) bag. 047 * <p> 048 * If there are any elements already in the bag being decorated, they 049 * are validated. 050 * 051 * @param <E> the type of the elements in the bag 052 * @param bag the bag to decorate, must not be null 053 * @param predicate the predicate to use for validation, must not be null 054 * @return a new predicated SortedBag 055 * @throws IllegalArgumentException if bag or predicate is null 056 * @throws IllegalArgumentException if the bag contains invalid elements 057 * @since 4.0 058 */ 059 public static <E> PredicatedSortedBag<E> predicatedSortedBag(final SortedBag<E> bag, 060 final Predicate<? super E> predicate) { 061 return new PredicatedSortedBag<E>(bag, predicate); 062 } 063 064 //----------------------------------------------------------------------- 065 /** 066 * Constructor that wraps (not copies). 067 * <p>If there are any elements already in the bag being decorated, they 068 * are validated. 069 * 070 * @param bag the bag to decorate, must not be null 071 * @param predicate the predicate to use for validation, must not be null 072 * @throws IllegalArgumentException if bag or predicate is null 073 * @throws IllegalArgumentException if the bag contains invalid elements 074 */ 075 protected PredicatedSortedBag(final SortedBag<E> bag, final Predicate<? super E> predicate) { 076 super(bag, predicate); 077 } 078 079 /** 080 * Gets the decorated sorted bag. 081 * 082 * @return the decorated bag 083 */ 084 @Override 085 protected SortedBag<E> decorated() { 086 return (SortedBag<E>) super.decorated(); 087 } 088 089 //----------------------------------------------------------------------- 090 091 public E first() { 092 return decorated().first(); 093 } 094 095 public E last() { 096 return decorated().last(); 097 } 098 099 public Comparator<? super E> comparator() { 100 return decorated().comparator(); 101 } 102 103}