1 /*
2 * Copyright (c) 2003 The Visigoth Software Society. All rights
3 * reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
15 * distribution.
16 *
17 * 3. The end-user documentation included with the redistribution, if
18 * any, must include the following acknowledgement:
19 * "This product includes software developed by the
20 * Visigoth Software Society (http://www.visigoths.org/)."
21 * Alternately, this acknowledgement may appear in the software itself,
22 * if and wherever such third-party acknowledgements normally appear.
23 *
24 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
25 * project contributors may be used to endorse or promote products derived
26 * from this software without prior written permission. For written
27 * permission, please contact visigoths@visigoths.org.
28 *
29 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
30 * nor may "FreeMarker" or "Visigoth" appear in their names
31 * without prior written permission of the Visigoth Software Society.
32 *
33 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
34 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
36 * DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
37 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
38 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
39 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
40 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
41 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
42 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
43 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 * ====================================================================
46 *
47 * This software consists of voluntary contributions made by many
48 * individuals on behalf of the Visigoth Software Society. For more
49 * information on the Visigoth Software Society, please see
50 * http://www.visigoths.org/
51 */
52
53 package freemarker.template.utility;
54
55 import freemarker.template.SimpleNumber;
56 import freemarker.template.TemplateBooleanModel;
57 import freemarker.template.TemplateCollectionModel;
58 import freemarker.template.TemplateHashModelEx;
59 import freemarker.template.TemplateModel;
60 import freemarker.template.TemplateModelException;
61 import freemarker.template.TemplateModelIterator;
62 import freemarker.template.TemplateNumberModel;
63 import freemarker.template.TemplateScalarModel;
64 import freemarker.template.TemplateSequenceModel;
65
66 /**
67 * Frequently used constant {@link TemplateModel} values.
68 *
69 * <p>These constants should be stored in the {@link TemplateModel}
70 * sub-interfaces, but for bacward compatibility they are stored here instead.
71 * Starting from FreeMarker 2.4 they should be copyed (not moved!) into the
72 * {@link TemplateModel} sub-interfaces, and this class should be marked as
73 * deprecated.</p>
74 *
75 * @version $Id: Constants.java,v 1.2 2004/11/28 12:58:34 ddekany Exp $
76 */
77 public class Constants {
78
79 public static final TemplateBooleanModel TRUE = TemplateBooleanModel.TRUE;
80
81 public static final TemplateBooleanModel FALSE = TemplateBooleanModel.FALSE;
82
83 public static final TemplateScalarModel EMPTY_STRING = (TemplateScalarModel) TemplateScalarModel.EMPTY_STRING;
84
85 public static final TemplateNumberModel ZERO = new SimpleNumber(0);
86
87 public static final TemplateNumberModel ONE = new SimpleNumber(1);
88
89 public static final TemplateNumberModel MINUS_ONE = new SimpleNumber(-1);
90
91 public static final TemplateModelIterator EMPTY_ITERATOR = new TemplateModelIterator() {
92
93 public TemplateModel next() throws TemplateModelException {
94 throw new TemplateModelException("The collection has no more elements.");
95 }
96
97 public boolean hasNext() throws TemplateModelException {
98 return false;
99 }
100
101 };
102
103 public static final TemplateCollectionModel EMPTY_COLLECTION = new TemplateCollectionModel() {
104
105 public TemplateModelIterator iterator() throws TemplateModelException {
106 return EMPTY_ITERATOR;
107 }
108
109 };
110
111 public static final TemplateSequenceModel EMPTY_SEQUENCE
112 = new TemplateSequenceModel() {
113
114 public TemplateModel get(int index) throws TemplateModelException {
115 return null;
116 }
117
118 public int size() throws TemplateModelException {
119 return 0;
120 }
121
122 };
123
124 public static final TemplateHashModelEx EMPTY_HASH = new TemplateHashModelEx() {
125
126 public int size() throws TemplateModelException {
127 return 0;
128 }
129
130 public TemplateCollectionModel keys() throws TemplateModelException {
131 return EMPTY_COLLECTION;
132 }
133
134 public TemplateCollectionModel values() throws TemplateModelException {
135 return EMPTY_COLLECTION;
136 }
137
138 public TemplateModel get(String key) throws TemplateModelException {
139 return null;
140 }
141
142 public boolean isEmpty() throws TemplateModelException {
143 return true;
144 }
145
146 };
147
148 }