001 /**
002 * GRANITE DATA SERVICES
003 * Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004 *
005 * This file is part of the Granite Data Services Platform.
006 *
007 * Granite Data Services is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * Granite Data Services is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015 * General Public License for more details.
016 *
017 * You should have received a copy of the GNU Lesser General Public
018 * License along with this library; if not, write to the Free Software
019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020 * USA, or see <http://www.gnu.org/licenses/>.
021 */
022 package org.granite.gravity.selector;
023
024 import java.math.BigDecimal;
025
026 import javax.jms.JMSException;
027
028 /**
029 * Represents a constant expression
030 *
031 * @version $Revision: 1.2 $
032 */
033 public class ConstantExpression implements Expression {
034
035 static class BooleanConstantExpression extends ConstantExpression implements BooleanExpression {
036 public BooleanConstantExpression(Object value) {
037 super(value);
038 }
039 public boolean matches(MessageEvaluationContext message) throws JMSException {
040 Object object = evaluate(message);
041 return object!=null && object==Boolean.TRUE;
042 }
043 }
044
045 public static final BooleanConstantExpression NULL = new BooleanConstantExpression(null);
046 public static final BooleanConstantExpression TRUE = new BooleanConstantExpression(Boolean.TRUE);
047 public static final BooleanConstantExpression FALSE = new BooleanConstantExpression(Boolean.FALSE);
048
049 private Object value;
050
051 public static ConstantExpression createFromDecimal(String text) {
052
053 // Strip off the 'l' or 'L' if needed.
054 if( text.endsWith("l") || text.endsWith("L") )
055 text = text.substring(0, text.length()-1);
056
057 Number value;
058 try {
059 value = new Long(text);
060 } catch ( NumberFormatException e) {
061 // The number may be too big to fit in a long.
062 value = new BigDecimal(text);
063 }
064
065 long l = value.longValue();
066 if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE) {
067 value = new Integer(value.intValue());
068 }
069 return new ConstantExpression(value);
070 }
071
072 public static ConstantExpression createFromHex(String text) {
073 Number value = new Long(Long.parseLong(text.substring(2), 16));
074 long l = value.longValue();
075 if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE) {
076 value = new Integer(value.intValue());
077 }
078 return new ConstantExpression(value);
079 }
080
081 public static ConstantExpression createFromOctal(String text) {
082 Number value = new Long(Long.parseLong(text, 8));
083 long l = value.longValue();
084 if (Integer.MIN_VALUE <= l && l <= Integer.MAX_VALUE) {
085 value = new Integer(value.intValue());
086 }
087 return new ConstantExpression(value);
088 }
089
090 public static ConstantExpression createFloat(String text) {
091 Number value = new Double(text);
092 return new ConstantExpression(value);
093 }
094
095 public ConstantExpression(Object value) {
096 this.value = value;
097 }
098
099 public Object evaluate(MessageEvaluationContext message) throws JMSException {
100 return value;
101 }
102
103 public Object getValue() {
104 return value;
105 }
106
107 /**
108 * @see java.lang.Object#toString()
109 */
110 @Override
111 public String toString() {
112 if (value == null) {
113 return "NULL";
114 }
115 if (value instanceof Boolean) {
116 return ((Boolean) value).booleanValue() ? "TRUE" : "FALSE";
117 }
118 if (value instanceof String) {
119 return encodeString((String) value);
120 }
121 return value.toString();
122 }
123
124 /**
125 * TODO: more efficient hashCode()
126 *
127 * @see java.lang.Object#hashCode()
128 */
129 @Override
130 public int hashCode() {
131 return toString().hashCode();
132 }
133
134 /**
135 * TODO: more efficient hashCode()
136 *
137 * @see java.lang.Object#equals(java.lang.Object)
138 */
139 @Override
140 public boolean equals(Object o) {
141
142 if (o == null || !this.getClass().equals(o.getClass())) {
143 return false;
144 }
145 return toString().equals(o.toString());
146
147 }
148
149
150 /**
151 * Encodes the value of string so that it looks like it would look like
152 * when it was provided in a selector.
153 *
154 * @param s the string to encode
155 * @return the encoded string
156 */
157 public static String encodeString(String s) {
158 StringBuffer b = new StringBuffer();
159 b.append('\'');
160 for (int i = 0; i < s.length(); i++) {
161 char c = s.charAt(i);
162 if (c == '\'') {
163 b.append(c);
164 }
165 b.append(c);
166 }
167 b.append('\'');
168 return b.toString();
169 }
170
171 }