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 */ 017 package org.apache.commons.chain.impl; 018 019 020 import java.util.HashMap; 021 import java.util.Collections; 022 import java.util.Iterator; 023 import java.util.Map; 024 import org.apache.commons.chain.Catalog; 025 import org.apache.commons.chain.Command; 026 027 028 /** 029 * <p>Simple in-memory implementation of {@link Catalog}. This class can 030 * also be used as the basis for more advanced implementations.</p> 031 * 032 * <p>This implementation is thread-safe.</p> 033 * 034 * @author Craig R. McClanahan 035 * @author Matthew J. Sgarlata 036 * @version $Revision: 480477 $ $Date: 2006-11-29 08:34:52 +0000 (Wed, 29 Nov 2006) $ 037 */ 038 039 public class CatalogBase implements Catalog { 040 041 042 // ----------------------------------------------------- Instance Variables 043 044 045 /** 046 * <p>The map of named {@link Command}s, keyed by name. 047 */ 048 protected Map commands = Collections.synchronizedMap(new HashMap()); 049 050 051 // --------------------------------------------------------- Constructors 052 053 /** 054 * Create an empty catalog. 055 */ 056 public CatalogBase() { } 057 058 /** 059 * <p>Create a catalog whose commands are those specified in the given <code>Map</code>. 060 * All Map keys should be <code>String</code> and all values should be <code>Command</code>.</p> 061 * 062 * @param commands Map of Commands. 063 * 064 * @since Chain 1.1 065 */ 066 public CatalogBase( Map commands ) { 067 this.commands = Collections.synchronizedMap(commands); 068 } 069 070 // --------------------------------------------------------- Public Methods 071 072 073 /** 074 * <p>Add a new name and associated {@link Command} 075 * to the set of named commands known to this {@link Catalog}, 076 * replacing any previous command for that name. 077 * 078 * @param name Name of the new command 079 * @param command {@link Command} to be returned 080 * for later lookups on this name 081 */ 082 public void addCommand(String name, Command command) { 083 084 commands.put(name, command); 085 086 } 087 088 /** 089 * <p>Return the {@link Command} associated with the 090 * specified name, if any; otherwise, return <code>null</code>.</p> 091 * 092 * @param name Name for which a {@link Command} 093 * should be retrieved 094 * @return The Command associated with the specified name. 095 */ 096 public Command getCommand(String name) { 097 098 return ((Command) commands.get(name)); 099 100 } 101 102 103 /** 104 * <p>Return an <code>Iterator</code> over the set of named commands 105 * known to this {@link Catalog}. If there are no known commands, 106 * an empty Iterator is returned.</p> 107 * @return An iterator of the names in this Catalog. 108 */ 109 public Iterator getNames() { 110 111 return (commands.keySet().iterator()); 112 113 } 114 115 /** 116 * Converts this Catalog to a String. Useful for debugging purposes. 117 * @return a representation of this catalog as a String 118 */ 119 public String toString() { 120 121 Iterator names = getNames(); 122 StringBuffer str = 123 new StringBuffer("[" + this.getClass().getName() + ": "); 124 125 while (names.hasNext()) { 126 str.append(names.next()); 127 if (names.hasNext()) { 128 str.append(", "); 129 } 130 } 131 str.append("]"); 132 133 return str.toString(); 134 135 } 136 }