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Java > Open Source Codes > org > apache > commons > chain > impl > NonDelegatingCommand


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 org.apache.commons.chain.Command;
20 import org.apache.commons.chain.Context;
21
22
23 /**
24  * <p>Implementation of {@link Command} that simply logs its identifier
25  * and returns.</p>
26  *
27  * @author Craig R. McClanahan
28  * @version $Revision: 1.6 $ $Date: 2004/02/25 00:01:05 $
29  */
30
31 public class NonDelegatingCommand implements Command {
32
33
34     // ------------------------------------------------------------ Constructor
35
36
37     public NonDelegatingCommand() {
38     this("");
39     }
40
41
42     // Construct an instance that will log the specified identifier
43 public NonDelegatingCommand(String JavaDoc id) {
44         this.id = id;
45     }
46
47
48     // ----------------------------------------------------- Instance Variables
49
50
51     // The identifier to log for this Command instance
52 protected String JavaDoc id = null;
53
54     String JavaDoc getId() {
55         return (this.id);
56     }
57
58     public void setId(String JavaDoc id) {
59     this.id = id;
60     }
61
62
63     // -------------------------------------------------------- Command Methods
64
65
66     // Execution method for this Command
67 public boolean execute(Context context) throws Exception JavaDoc {
68
69         if (context == null) {
70             throw new IllegalArgumentException JavaDoc();
71         }
72         log(context, id);
73         return (true);
74
75     }
76
77
78
79     // ------------------------------------------------------ Protected Methods
80
81
82     /**
83      * <p>Log the specified <code>id</code> into a StringBuffer attribute
84      * named "log" in the specified <code>context</code>, creating it if
85      * necessary.</p>
86      *
87      * @param context The {@link Context} into which we log the identifiers
88      * @param id The identifier to be logged
89      */
90     protected void log(Context context, String JavaDoc id) {
91         StringBuffer JavaDoc sb = (StringBuffer JavaDoc) context.get("log");
92         if (sb == null) {
93             sb = new StringBuffer JavaDoc();
94             context.put("log", sb);
95         }
96         if (sb.length() > 0) {
97             sb.append('/');
98         }
99         sb.append(id);
100     }
101
102
103 }
104
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