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;
54
55 /**
56 * <p>An extended hash interface with a couple of extra hooks. If a class
57 * implements this interface, then the built-in operators <code>?size</code>,
58 * <code>?keys</code>, and <code>?values</code> can be applied to its
59 * instances in the template.</p>
60 *
61 * <p>As of version 2.2.2, the engine will automatically wrap the
62 * collections returned by <code>keys</code> and <code>values</code> to
63 * present them as sequences to the template. For performance, you may
64 * wish to return objects that implement both TemplateCollectionModel
65 * and {@link TemplateSequenceModel}. Note that the wrapping to sequence happens
66 * on demand; if the template does not try to use the variable returned by
67 * <code>?keys</code> or <code>?values</code> as sequence (<code>theKeys?size</code>, or <code>theKeys[x]</code>,
68 * or <code>theKeys?sort</code>, etc.), just iterates over the variable
69 * (<code><#list foo?keys as k>...</code>), then no wrapping to
70 * sequence will happen, thus there will be no overhead.
71 *
72 * @author <a href="mailto:jon@revusky.com">Jonathan Revusky</a>
73 * @see SimpleHash
74 * @version $Id: TemplateHashModelEx.java,v 1.13 2003/06/08 00:58:15 herbyderby Exp $
75 */
76 public interface TemplateHashModelEx extends TemplateHashModel {
77
78 /**
79 * @return the number of key/value mappings in the hash.
80 */
81 int size() throws TemplateModelException;
82
83 /**
84 * @return a collection containing the keys in the hash. Every element of
85 * the returned collection must implement the {@link TemplateScalarModel}
86 * (as the keys of hashes are always strings).
87 */
88 TemplateCollectionModel keys() throws TemplateModelException;
89
90 /**
91 * @return a collection containing the values in the hash.
92 */
93 TemplateCollectionModel values() throws TemplateModelException;
94 }
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