001/* 002 * This library is part of OpenCms - 003 * the Open Source Content Management System 004 * 005 * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) 006 * 007 * This library is free software; you can redistribute it and/or 008 * modify it under the terms of the GNU Lesser General Public 009 * License as published by the Free Software Foundation; either 010 * version 2.1 of the License, or (at your option) any later version. 011 * 012 * This library is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * For further information about Alkacon Software, please see the 018 * company website: http://www.alkacon.com 019 * 020 * For further information about OpenCms, please see the 021 * project website: http://www.opencms.org 022 * 023 * You should have received a copy of the GNU Lesser General Public 024 * License along with this library; if not, write to the Free Software 025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 026 */ 027 028package org.opencms.util; 029 030import java.util.Enumeration; 031import java.util.HashMap; 032import java.util.List; 033import java.util.Map; 034 035import org.apache.commons.collections.Transformer; 036import org.apache.commons.collections.map.LRUMap; 037import org.apache.commons.collections.map.LazyMap; 038 039/** 040 * Provides Map wrapping utility functions for Java generics.<p> 041 * 042 * @since 8.0.0 043 */ 044public final class CmsCollectionsGenericWrapper { 045 046 /** 047 * Hides the public constructor.<p> 048 */ 049 private CmsCollectionsGenericWrapper() { 050 051 // empty 052 } 053 054 /** 055 * Provides a wrapper to access the {@link LazyMap} functionality that avoids warnings with Java 1.5 generic code.<p> 056 * 057 * @param <K> the type of keys maintained by the returned map 058 * @param <V> the type of mapped values 059 * @param T the transformer to use for the Lazy Map 060 * 061 * @return a {@link LazyMap} of the required generic type 062 */ 063 public static <K, V> Map<K, V> createLazyMap(Transformer T) { 064 065 return LazyMap.decorate(new HashMap<K, V>(), T); 066 } 067 068 /** 069 * Provides a wrapper to create a {@link LRUMap} that avoids warnings with Java 1.5 generic code.<p> 070 * 071 * @param <K> the type of keys maintained by the returned map 072 * @param <V> the type of mapped values 073 * 074 * @return a {@link LRUMap} of the required generic type 075 */ 076 @SuppressWarnings("unchecked") 077 public static <K, V> Map<K, V> createLRUMap() { 078 079 return new LRUMap(); 080 } 081 082 /** 083 * Provides a wrapper to create a {@link LRUMap} with the given size that avoids warnings with Java 1.5 generic code.<p> 084 * 085 * @param <K> the type of keys maintained by the returned map 086 * @param <V> the type of mapped values 087 * @param size the initial size of the created Map 088 * 089 * @return a {@link LRUMap} with the given size of the required generic type 090 */ 091 @SuppressWarnings("unchecked") 092 public static <K, V> Map<K, V> createLRUMap(int size) { 093 094 return new LRUMap(size); 095 } 096 097 /** 098 * Provides a wrapper to convert an enumeration that avoids warnings with Java 1.5 generic code.<p> 099 * 100 * @param <K> the type of the returned enumeration elements 101 * @param enumeration the enumeration to be converted 102 * 103 * @return a {@link Enumeration} with the required generic type 104 */ 105 @SuppressWarnings("unchecked") 106 public static <K> Enumeration<K> enumeration(Enumeration<?> enumeration) { 107 108 return (Enumeration<K>)enumeration; 109 } 110 111 /** 112 * Provides a wrapper to convert an object into a list that avoids warnings with Java 1.5 generic code.<p> 113 * 114 * @param <K> the type of the returned list elements 115 * @param o the object to be converted 116 * 117 * @return a {@link List} with the required generic type 118 */ 119 @SuppressWarnings("unchecked") 120 public static <K> List<K> list(Object o) { 121 122 return (List<K>)o; 123 } 124 125 /** 126 * Provides a wrapper to convert an object into a map that avoids warnings with Java 1.5 generic code.<p> 127 * 128 * @param <K> the type of keys maintained by the returned map 129 * @param <V> the type of mapped values 130 * @param o the object to be converted 131 * 132 * @return a {@link Map} of the required generic type 133 */ 134 @SuppressWarnings("unchecked") 135 public static <K, V> Map<K, V> map(Object o) { 136 137 return (Map<K, V>)o; 138 } 139}