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
18 package javax.servlet.jsp.tagext;
19
20 import java.util.Hashtable;
21
22 /**
23 * The (translation-time only) attribute/value information for a tag instance.
24 *
25 * <p>
26 * TagData is only used as an argument to the isValid, validate, and
27 * getVariableInfo methods of TagExtraInfo, which are invoked at
28 * translation time.
29 */
30
31 public class TagData implements Cloneable {
32
33 /**
34 * Distinguished value for an attribute to indicate its value
35 * is a request-time expression (which is not yet available because
36 * TagData instances are used at translation-time).
37 */
38
39 public static final Object REQUEST_TIME_VALUE = new Object();
40
41
42 /**
43 * Constructor for TagData.
44 *
45 * <p>
46 * A typical constructor may be
47 * <pre>
48 * static final Object[][] att = {{"connection", "conn0"}, {"id", "query0"}};
49 * static final TagData td = new TagData(att);
50 * </pre>
51 *
52 * All values must be Strings except for those holding the
53 * distinguished object REQUEST_TIME_VALUE.
54
55 * @param atts the static attribute and values. May be null.
56 */
57 public TagData(Object[] atts[]) {
58 if (atts == null) {
59 attributes = new Hashtable<String, Object>();
60 } else {
61 attributes = new Hashtable<String, Object>(atts.length);
62 }
63
64 if (atts != null) {
65 for (int i = 0; i < atts.length; i++) {
66 attributes.put((String) atts[i][0], atts[i][1]);
67 }
68 }
69 }
70
71 /**
72 * Constructor for a TagData.
73 *
74 * If you already have the attributes in a hashtable, use this
75 * constructor.
76 *
77 * @param attrs A hashtable to get the values from.
78 */
79 public TagData(Hashtable<String, Object> attrs) {
80 this.attributes = attrs;
81 }
82
83 /**
84 * The value of the tag's id attribute.
85 *
86 * @return the value of the tag's id attribute, or null if no such
87 * attribute was specified.
88 */
89
90 public String getId() {
91 return getAttributeString(TagAttributeInfo.ID);
92 }
93
94 /**
95 * The value of the attribute.
96 * If a static value is specified for an attribute that accepts a
97 * request-time attribute expression then that static value is returned,
98 * even if the value is provided in the body of a <jsp:attribute> action.
99 * The distinguished object REQUEST_TIME_VALUE is only returned if
100 * the value is specified as a request-time attribute expression
101 * or via the <jsp:attribute> action with a body that contains
102 * dynamic content (scriptlets, scripting expressions, EL expressions,
103 * standard actions, or custom actions). Returns null if the attribute
104 * is not set.
105 *
106 * @param attName the name of the attribute
107 * @return the attribute's value
108 */
109
110 public Object getAttribute(String attName) {
111 return attributes.get(attName);
112 }
113
114 /**
115 * Set the value of an attribute.
116 *
117 * @param attName the name of the attribute
118 * @param value the value.
119 */
120 public void setAttribute(String attName,
121 Object value) {
122 attributes.put(attName, value);
123 }
124
125 /**
126 * Get the value for a given attribute.
127 *
128 * @param attName the name of the attribute
129 * @return the attribute value string
130 * @throws ClassCastException if attribute value is not a String
131 */
132
133 public String getAttributeString(String attName) {
134 Object o = attributes.get(attName);
135 if (o == null) {
136 return null;
137 } else {
138 return (String) o;
139 }
140 }
141
142 /**
143 * Enumerates the attributes.
144 *
145 *@return An enumeration of the attributes in a TagData
146 */
147 public java.util.Enumeration<String> getAttributes() {
148 return attributes.keys();
149 };
150
151 // private data
152
153 private Hashtable<String, Object> attributes; // the tagname/value map
154 }