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Java > Open Source Codes > freemarker > template > utility > ObjectConstructor


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
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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 java.util.List JavaDoc;
56 import freemarker.ext.beans.BeansWrapper;
57 import freemarker.template.*;
58 import freemarker.template.utility.ClassUtil;
59
60 /**
61  * An object that you can make available in a template
62  * to instantiate arbitrary beans-wrapped objects in a template.
63  * Beware of this class's security implications. It allows
64  * the instantiation of arbitrary objects and invoking
65  * methods on them. Usage is something like:
66  * <br>
67  * <br>myDataModel.put("objectConstructor", new ObjectConstructor());
68  * <br>
69  * <br>And then from your FTL code:
70  * <br>
71  * <br>&lt;#assign aList = objectConstructor("java.util.ArrayList", 100)&gt;
72  */
73
74 public class ObjectConstructor implements TemplateMethodModelEx
75 {
76     public Object JavaDoc exec(List JavaDoc args) throws TemplateModelException {
77         if (args.isEmpty()) {
78             throw new TemplateModelException("This method must have at least one argument, the name of the class to instantiate.");
79         }
80         String JavaDoc classname = args.get(0).toString();
81         Class JavaDoc cl = null;
82         try {
83             cl = ClassUtil.forName(classname);
84         }
85         catch (Exception JavaDoc e) {
86             throw new TemplateModelException(e.getMessage());
87         }
88         BeansWrapper bw = BeansWrapper.getDefaultInstance();
89         Object JavaDoc obj = bw.newInstance(cl, args.subList(1, args.size()));
90         return bw.wrap(obj);
91     }
92 }
93
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