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1   /*
2    * Copyright 1999-2004 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.chain.impl;
17  
18  
19  import java.util.HashMap;
20  import java.util.Collections;
21  import java.util.Iterator;
22  import java.util.Map;
23  import org.apache.commons.chain.Catalog;
24  import org.apache.commons.chain.Command;
25  
26  
27  /***
28   * <p>Simple in-memory implementation of {@link Catalog}.  This class can
29   * also be used as the basis for more advanced implementations.</p>
30   *
31   * <p>This implementation is thread-safe.</p>
32   *
33   * @author Craig R. McClanahan
34   * @author Matthew J. Sgarlata
35   * @version $Revision: 411876 $ $Date: 2006-06-05 19:02:19 +0100 (Mon, 05 Jun 2006) $
36   */
37  
38  public class CatalogBase implements Catalog {
39  
40  
41      // ----------------------------------------------------- Instance Variables
42  
43  
44      /***
45       * <p>The map of named {@link Command}s, keyed by name.
46       */
47      protected Map commands = Collections.synchronizedMap(new HashMap());
48  
49  
50      // --------------------------------------------------------- Constructors
51  
52      /***
53       * Create an empty catalog.
54       */
55      public CatalogBase() { }
56  
57      /***
58       * <p>Create a catalog whose commands are those specified in the given <code>Map</code>.
59       * All Map keys should be <code>String</code> and all values should be <code>Command</code>.</p>
60       *
61       * @param commands Map of Commands.
62       *
63       * @since Chain 1.1
64       */
65      public CatalogBase( Map commands ) {
66          this.commands = Collections.synchronizedMap(commands);
67      }
68  
69      // --------------------------------------------------------- Public Methods
70  
71  
72      /***
73       * <p>Add a new name and associated {@link Command}
74       * to the set of named commands known to this {@link Catalog},
75       * replacing any previous command for that name.
76       *
77       * @param name Name of the new command
78       * @param command {@link Command} to be returned
79       *  for later lookups on this name
80       */
81      public void addCommand(String name, Command command) {
82  
83          commands.put(name, command);
84  
85      }
86  
87      /***
88       * <p>Return the {@link Command} associated with the
89       * specified name, if any; otherwise, return <code>null</code>.</p>
90       *
91       * @param name Name for which a {@link Command}
92       *  should be retrieved
93       * @return The Command associated with the specified name.
94       */
95      public Command getCommand(String name) {
96  
97          return ((Command) commands.get(name));
98  
99      }
100 
101 
102     /***
103      * <p>Return an <code>Iterator</code> over the set of named commands
104      * known to this {@link Catalog}.  If there are no known commands,
105      * an empty Iterator is returned.</p>
106      * @return An iterator of the names in this Catalog.
107      */
108     public Iterator getNames() {
109 
110         return (commands.keySet().iterator());
111 
112     }
113 
114     /***
115      * Converts this Catalog to a String.  Useful for debugging purposes.
116      * @return a representation of this catalog as a String
117      */
118     public String toString() {
119 
120         Iterator names = getNames();
121         StringBuffer str =
122             new StringBuffer("[" + this.getClass().getName() + ": ");
123 
124         while (names.hasNext()) {
125             str.append(names.next());
126             if (names.hasNext()) {
127             str.append(", ");
128             }
129         }
130         str.append("]");
131 
132         return str.toString();
133 
134     }
135 }