1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.chain.impl; 18 19 20 import java.util.HashMap; 21 import java.util.Collections; 22 import java.util.Iterator; 23 import java.util.Map; 24 import org.apache.commons.chain.Catalog; 25 import org.apache.commons.chain.Command; 26 27 28 /** 29 * <p>Simple in-memory implementation of {@link Catalog}. This class can 30 * also be used as the basis for more advanced implementations.</p> 31 * 32 * <p>This implementation is thread-safe.</p> 33 * 34 * @author Craig R. McClanahan 35 * @author Matthew J. Sgarlata 36 * @version $Revision: 480477 $ $Date: 2006-11-29 08:34:52 +0000 (Wed, 29 Nov 2006) $ 37 */ 38 39 public class CatalogBase implements Catalog { 40 41 42 // ----------------------------------------------------- Instance Variables 43 44 45 /** 46 * <p>The map of named {@link Command}s, keyed by name. 47 */ 48 protected Map commands = Collections.synchronizedMap(new HashMap()); 49 50 51 // --------------------------------------------------------- Constructors 52 53 /** 54 * Create an empty catalog. 55 */ 56 public CatalogBase() { } 57 58 /** 59 * <p>Create a catalog whose commands are those specified in the given <code>Map</code>. 60 * All Map keys should be <code>String</code> and all values should be <code>Command</code>.</p> 61 * 62 * @param commands Map of Commands. 63 * 64 * @since Chain 1.1 65 */ 66 public CatalogBase( Map commands ) { 67 this.commands = Collections.synchronizedMap(commands); 68 } 69 70 // --------------------------------------------------------- Public Methods 71 72 73 /** 74 * <p>Add a new name and associated {@link Command} 75 * to the set of named commands known to this {@link Catalog}, 76 * replacing any previous command for that name. 77 * 78 * @param name Name of the new command 79 * @param command {@link Command} to be returned 80 * for later lookups on this name 81 */ 82 public void addCommand(String name, Command command) { 83 84 commands.put(name, command); 85 86 } 87 88 /** 89 * <p>Return the {@link Command} associated with the 90 * specified name, if any; otherwise, return <code>null</code>.</p> 91 * 92 * @param name Name for which a {@link Command} 93 * should be retrieved 94 * @return The Command associated with the specified name. 95 */ 96 public Command getCommand(String name) { 97 98 return ((Command) commands.get(name)); 99 100 } 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 }