Source code: gnu/java/beans/decoder/PropertyContext.java
1 /* gnu.java.beans.decoder.PropertyContext
2 Copyright (C) 2004 Free Software Foundation, Inc.
3
4 This file is part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38 package gnu.java.beans.decoder;
39
40 import java.lang.reflect.InvocationTargetException;
41 import java.lang.reflect.Method;
42
43 /** PropertyContext is a Context implementation that is very similar to MethodContext
44 * and IndexContext. The sole purpose of PropertyContext to find out whether it should
45 * 'set' or 'get' a certain property. This decision is made using the number of
46 * arguments.
47 * <p>When the method call has to be made and there is no argument we 'get' the property.
48 * With one argument it is 'set'.</p>
49 *
50 * @author Robert Schuster
51 */
52 class PropertyContext extends AbstractObjectContext
53 {
54 private Object argument;
55 private String propertyName;
56 private String prefix = "get";
57 private boolean methodCalled;
58
59 PropertyContext(String id, String newPropertyName)
60 {
61 setId(id);
62 propertyName = newPropertyName;
63 }
64
65 /* (non-Javadoc)
66 * @see gnu.java.beans.decoder.Context#addObject(java.lang.Object)
67 */
68 public void addParameterObject(Object o) throws AssemblyException
69 {
70 if (methodCalled)
71 throw new AssemblyException(new IllegalArgumentException("Cannot add parameter object when method was already called."));
72
73 if (argument != null)
74 throw new AssemblyException(new IllegalArgumentException("Property attribut allows zero or one argument only."));
75
76 argument = o;
77 setStatement(true);
78 prefix = "set";
79 }
80
81 /* (non-Javadoc)
82 * @see gnu.java.beans.decoder.Context#endContext(gnu.java.beans.decoder.Context)
83 */
84 public void notifyStatement(Context outerContext) throws AssemblyException
85 {
86 if (methodCalled)
87 return;
88 methodCalled = true;
89
90 Object outerObject = outerContext.getResult();
91
92 if (outerObject == null)
93 throw new AssemblyException(new NullPointerException("No object to access property "
94 + propertyName));
95
96
97 // converts property name into a method name
98 String methodName = prefix + propertyName.substring(0, 1).toUpperCase()
99 + propertyName.substring(1);
100
101 // prepares the argument
102 Object[] args = (argument != null) ? new Object[] { argument } : null;
103
104 try
105 {
106 Method method = MethodFinder.getMethod(outerObject.getClass(),
107 methodName, args);
108
109 // stores the result whether it is available or not
110 setObject(method.invoke(outerObject, args));
111 }
112 catch (NoSuchMethodException nsme)
113 {
114 throw new AssemblyException(nsme);
115 }
116 catch (InvocationTargetException ite)
117 {
118 throw new AssemblyException(ite.getCause());
119 }
120 catch (IllegalAccessException iae)
121 {
122 throw new AssemblyException(iae);
123 }
124 }
125
126 public Object endContext(Context outerContext) throws AssemblyException
127 {
128 notifyStatement(outerContext);
129
130 return getResult();
131 }
132
133 public boolean subContextFailed()
134 {
135 return ! methodCalled;
136 }
137 }