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Java > Open Source Codes > org > jfree > xml > factory > objects > ArrayObjectDescription


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ---------------------------
28  * ArrayObjectDescription.java
29  * ---------------------------
30  * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
31  *
32  * Original Author: Thomas Morgner (taquera@sherito.org);
33  * Contributor(s): David Gilbert (for Object Refinery Limited);
34  *
35  * $Id: ArrayObjectDescription.java,v 1.4 2006/01/27 18:53:15 taqua Exp $
36  *
37  * Changes
38  * -------
39  * 14-Apr-2003 : Initial version
40  * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon
41  */
42 package org.jfree.xml.factory.objects;
43
44 import java.lang.reflect.Array JavaDoc;
45 import java.util.ArrayList JavaDoc;
46 import java.util.Iterator JavaDoc;
47
48 import org.jfree.util.Log;
49
50 /**
51  * Describes an Object- or primitive value array. This object description is
52  * not intended to be created outside the ArrayClassFactory.
53  *
54  * @author Thomas Morgner
55  */
56 public class ArrayObjectDescription extends AbstractObjectDescription {
57
58     /**
59      * Constructs a new array objet description for the given array class.
60      * <P>
61      * Note: throws <code>IllegalArgumentException</code> if the given class is no array.
62      *
63      * @param c the array class object.
64      */
65     public ArrayObjectDescription(final Class JavaDoc c) {
66         super(c);
67         if (!c.isArray()) {
68             throw new IllegalArgumentException JavaDoc("Need an array class");
69         }
70     }
71
72     /**
73      * Creates an object based on the description.
74      *
75      * @return The object.
76      */
77     public Object JavaDoc createObject() {
78         try {
79             final Integer JavaDoc size = (Integer JavaDoc) getParameter("size");
80             if (size == null) {
81                 final ArrayList JavaDoc l = new ArrayList JavaDoc();
82                 int counter = 0;
83                 while (getParameterDefinition(String.valueOf(counter)) != null) {
84                     final Object JavaDoc value = getParameter(String.valueOf(counter));
85                     if (value == null) {
86                         break;
87                     }
88
89                     l.add(value);
90                     counter += 1;
91                 }
92
93                 final Object JavaDoc o = Array.newInstance
94                     (getObjectClass().getComponentType(), l.size());
95                 for (int i = 0; i < l.size(); i++) {
96                     Array.set(o, i, l.get(i));
97                 }
98                 return o;
99             }
100             else {
101                 // a size is given, so we can assume that all values are defined.
102 final Object JavaDoc o = Array.newInstance
103                     (getObjectClass().getComponentType(), size.intValue());
104                 for (int i = 0; i < size.intValue(); i++) {
105                     Array.set(o, i, getParameter(String.valueOf(i)));
106                 }
107                 return o;
108             }
109         }
110         catch (Exception JavaDoc ie) {
111             Log.warn("Unable to instantiate Object", ie);
112             return null;
113         }
114     }
115
116     /**
117      * Sets the parameters of this description object to match the supplied object.
118      *
119      * @param o the object.
120      *
121      * @throws ObjectFactoryException if there is a
122      * problem while reading the properties of the given object.
123      */
124     public void setParameterFromObject(final Object JavaDoc o) throws ObjectFactoryException {
125         if (o == null) {
126             throw new ObjectFactoryException("Given object is null.");
127         }
128
129         if (!o.getClass().isArray()) {
130             throw new ObjectFactoryException("Given object is no array");
131         }
132
133         if (!getObjectClass().isAssignableFrom(o.getClass())) {
134             throw new ObjectFactoryException("Given object is incompatible with base class");
135         }
136
137         final int size = Array.getLength(o);
138         setParameter("size", new Integer JavaDoc(size));
139         for (int i = 0; i < size; i++) {
140             setParameter(String.valueOf(i), Array.get(o, i));
141         }
142     }
143
144     /**
145      * Tries to parse the given parameter string into a positive integer.
146      * Returns -1 if the parsing failed for some reason.
147      *
148      * @param name the name of the parameter.
149      * @return the parsed int value or -1 on errors.
150      */
151     private int parseParameterName(final String JavaDoc name) {
152         try {
153             return Integer.parseInt(name);
154         }
155         catch (Exception JavaDoc e) {
156             return -1;
157         }
158     }
159
160     /**
161      * Returns a parameter definition. If the parameter is invalid, this
162      * function returns null.
163      *
164      * @param name the definition name.
165      *
166      * @return The parameter class or null, if the parameter is not defined.
167      */
168     public Class JavaDoc getParameterDefinition(final String JavaDoc name) {
169         if (name.equals("size")) {
170             return Integer.TYPE;
171         }
172         final int par = parseParameterName(name);
173         if (par < 0) {
174             return null;
175         }
176         return getObjectClass().getComponentType();
177     }
178
179     /**
180      * Returns an iterator for the parameter names.
181      *
182      * @return The iterator.
183      */
184     public Iterator JavaDoc getParameterNames() {
185         final Integer JavaDoc size = (Integer JavaDoc) getParameter("size");
186         if (size == null) {
187             return getDefinedParameterNames();
188         }
189         else {
190             final ArrayList JavaDoc l = new ArrayList JavaDoc();
191             l.add("size");
192             for (int i = 0; i < size.intValue(); i++) {
193                 l.add(String.valueOf(i));
194             }
195             return l.iterator();
196         }
197     }
198
199     /**
200      * Returns a new instance of the object description.
201      *
202      * @return The object description.
203      */
204     public ObjectDescription getInstance() {
205         return new ArrayObjectDescription(getObjectClass());
206     }
207 }
208
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