1 /*
2 * $Id: ResourceTag.java 471754 2006-11-06 14:55:09Z husted $
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21 package org.apache.struts.taglib.bean;
22
23 import org.apache.struts.taglib.TagUtils;
24 import org.apache.struts.util.MessageResources;
25
26 import javax.servlet.jsp.JspException;
27 import javax.servlet.jsp.tagext.TagSupport;
28
29 import java.io.IOException;
30 import java.io.InputStream;
31 import java.io.InputStreamReader;
32
33 /**
34 * Define a scripting variable based on the contents of the specified web
35 * application resource.
36 *
37 * @version $Rev: 471754 $ $Date: 2004-10-16 12:38:42 -0400 (Sat, 16 Oct 2004)
38 * $
39 */
40 public class ResourceTag extends TagSupport {
41 // ------------------------------------------------------------- Properties
42
43 /**
44 * Buffer size to use when reading the input stream.
45 */
46 protected static final int BUFFER_SIZE = 256;
47
48 /**
49 * The message resources for this package.
50 */
51 protected static MessageResources messages =
52 MessageResources.getMessageResources(
53 "org.apache.struts.taglib.bean.LocalStrings");
54
55 /**
56 * The name of the scripting variable that will be exposed as a page scope
57 * attribute.
58 */
59 protected String id = null;
60
61 /**
62 * Return an InputStream to the specified resource if this is non-null.
63 */
64 protected String input = null;
65
66 /**
67 * The module-relative URI of the resource whose contents are to be
68 * exposed.
69 */
70 protected String name = null;
71
72 public String getId() {
73 return (this.id);
74 }
75
76 public void setId(String id) {
77 this.id = id;
78 }
79
80 public String getInput() {
81 return (this.input);
82 }
83
84 public void setInput(String input) {
85 this.input = input;
86 }
87
88 public String getName() {
89 return (this.name);
90 }
91
92 public void setName(String name) {
93 this.name = name;
94 }
95
96 // --------------------------------------------------------- Public Methods
97
98 /**
99 * Retrieve the required property and expose it as a scripting variable.
100 *
101 * @throws JspException if a JSP exception has occurred
102 */
103 public int doStartTag() throws JspException {
104 // Acquire an input stream to the specified resource
105 InputStream stream =
106 pageContext.getServletContext().getResourceAsStream(name);
107
108 if (stream == null) {
109 JspException e =
110 new JspException(messages.getMessage("resource.get", name));
111
112 TagUtils.getInstance().saveException(pageContext, e);
113 throw e;
114 }
115
116 // If we are returning an InputStream, do so and return
117 if (input != null) {
118 pageContext.setAttribute(id, stream);
119
120 return (SKIP_BODY);
121 }
122
123 // Accumulate the contents of this resource into a StringBuffer
124 try {
125 StringBuffer sb = new StringBuffer();
126 InputStreamReader reader = new InputStreamReader(stream);
127 char[] buffer = new char[BUFFER_SIZE];
128 int n = 0;
129
130 while (true) {
131 n = reader.read(buffer);
132
133 if (n < 1) {
134 break;
135 }
136
137 sb.append(buffer, 0, n);
138 }
139
140 reader.close();
141 pageContext.setAttribute(id, sb.toString());
142 } catch (IOException e) {
143 TagUtils.getInstance().saveException(pageContext, e);
144 throw new JspException(messages.getMessage("resource.get", name));
145 }
146
147 return (SKIP_BODY);
148 }
149
150 /**
151 * Release all allocated resources.
152 */
153 public void release() {
154 super.release();
155 id = null;
156 input = null;
157 name = null;
158 }
159 }