1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2000,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42 */
43
44 package org.exolab.jms.selector;
45
46 import javax.jms.DeliveryMode;
47 import javax.jms.JMSException;
48 import javax.jms.Message;
49
50
51 /***
52 * This class implements an identifier. When evaluated, this returns
53 * the value of named header identifier or property, or null if the
54 * identifier is null or the property does not exist.
55 *
56 * @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:44 $
57 * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
58 * @see org.exolab.jms.selector.Expression
59 * @see org.exolab.jms.selector.Identifiers
60 */
61 class Identifier implements Expression {
62
63 /***
64 * The identifier name
65 */
66 private final String _name;
67
68 /***
69 * If true the identifier is a header identifier, otherwise it is an user
70 * identifier
71 */
72 private final boolean _headerField;
73
74 /***
75 * Persistent delivery mode
76 */
77 private static final SString PERSISTENT =
78 new SString(Identifiers.PERSISTENT);
79
80 /***
81 * Non-persistent delivery mode
82 */
83 private static final SString NON_PERSISTENT =
84 new SString(Identifiers.NON_PERSISTENT);
85
86
87 /***
88 * Construct a new <code>Identifier</code>
89 *
90 * @param name the identifier name
91 * @throws SelectorException if the identifier cannot be queried by
92 * selectors
93 */
94 public Identifier(final String name) throws SelectorException {
95 _name = name;
96
97 if (Identifiers.isJMSIdentifier(_name)) {
98 if (!Identifiers.isQueryableJMSIdentifier(_name)) {
99 throw new SelectorException("Invalid header field: " + _name);
100 }
101 _headerField = true;
102 } else {
103 _headerField = false;
104 }
105 }
106
107 /***
108 * Evaluate the expression
109 *
110 * @param msg the message to use to obtain any header identifier and
111 * property values
112 * @return the evaluated result, or <code>null</code> if the value of the
113 * expression is unknown
114 */
115 public final SObject evaluate(final Message msg) {
116 SObject value = null;
117 try {
118 if (_headerField) {
119 if (_name.equals(Identifiers.JMS_DELIVERY_MODE)) {
120 value = deliveryMode(msg.getJMSDeliveryMode());
121 } else if (_name.equals(Identifiers.JMS_PRIORITY)) {
122 value = new SLong(msg.getJMSPriority());
123 } else if (_name.equals(Identifiers.JMS_TIMESTAMP)) {
124 value = new SLong(msg.getJMSTimestamp());
125 } else if (_name.equals(Identifiers.JMS_MESSAGE_ID)) {
126 String id = msg.getJMSMessageID();
127 if (id != null) {
128 value = new SString(id);
129 }
130 } else if (_name.equals(Identifiers.JMS_CORRELATION_ID)) {
131 String id = msg.getJMSCorrelationID();
132 if (id != null) {
133 value = new SString(id);
134 }
135 } else if (_name.equals(Identifiers.JMS_TYPE)) {
136 String type = msg.getJMSType();
137 if (type != null) {
138 value = new SString(type);
139 }
140 }
141 } else {
142 value = SObjectFactory.create(msg.getObjectProperty(_name));
143 }
144 } catch (JMSException ignore) {
145
146 }
147 return value;
148 }
149
150 /***
151 * Return a string representation of this expression.
152 *
153 * @return a string representation of this expression
154 */
155 public final String toString() {
156 return _name;
157 }
158
159 /***
160 * Converts the delivery mode to a string
161 *
162 * @param mode the delivery mode. One of
163 * <code>DeliveryMode.PERSISTENT</code> or
164 * <code>DeliveryMode.NON_PERSISTENT</code>
165 * @return the stringified representation of the delivery mode
166 */
167 private SString deliveryMode(final int mode) {
168 SString result = PERSISTENT;
169 if (mode == DeliveryMode.NON_PERSISTENT) {
170 result = NON_PERSISTENT;
171 }
172 return result;
173 }
174
175 }