1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
/*******************************************************************************
* Copyright (c) 2008, 2009 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0, which accompanies this distribution
* and is available at http://www.eclipse.org/legal/epl-v10.html.
*
* Contributors:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.utility.internal.model.value;
import org.eclipse.jpt.utility.internal.BidiTransformer;
import org.eclipse.jpt.utility.model.value.WritablePropertyValueModel;
/**
* A <code>TransformationWritablePropertyValueModel</code> wraps another
* {@link WritablePropertyValueModel} and uses a {@link BidiTransformer}
* to:<ul>
* <li>transform the wrapped value before it is returned by {@link #getValue()}
* <li>"reverse-transform" the new value that comes in via
* {@link #setValue(Object)}
* </ul>
* As an alternative to building a {@link BidiTransformer},
* a subclass of <code>TransformationWritablePropertyValueModel</code> can
* override {@link #transform_(Object)} and {@link #reverseTransform_(Object)};
* or, if something other than null should be returned when the wrapped value
* is null or the new value is null, override {@link #transform(Object)}
* and {@link #reverseTransform(Object)}.
*/
public class TransformationWritablePropertyValueModel<T1, T2>
extends TransformationPropertyValueModel<T1, T2>
implements WritablePropertyValueModel<T2>
{
// ********** constructors/initialization **********
/**
* Construct a writable property value model with the specified nested
* writable property value model and the default bidi transformer.
* Use this constructor if you want to override the
* {@link #transform_(Object)} and {@link #reverseTransform_(Object)}
* (or {@link #transform(Object)} and {@link #reverseTransform(Object)})
* methods instead of building a {@link BidiTransformer}.
*/
public TransformationWritablePropertyValueModel(WritablePropertyValueModel<T1> valueHolder) {
super(valueHolder);
}
/**
* Construct a writable property value model with the specified nested
* writable property value model and bidi transformer.
*/
public TransformationWritablePropertyValueModel(WritablePropertyValueModel<T1> valueHolder, BidiTransformer<T1, T2> transformer) {
super(valueHolder, transformer);
}
@Override
protected BidiTransformer<T1, T2> buildTransformer() {
return new DefaultBidiTransformer();
}
// ********** WritablePropertyValueModel implementation **********
public void setValue(T2 value) {
// "reverse-transform" the object before passing it to the the nested value model
this.getValueHolder().setValue(this.reverseTransform(value));
}
// ********** behavior **********
/**
* "Reverse-transform" the specified value and return the result.
* This is called by {@link #setValue(Object)}.
*/
protected T1 reverseTransform(T2 value) {
return this.getTransformer().reverseTransform(value);
}
/**
* "Reverse-transform" the specified, non-null, value and return the result.
*/
protected T1 reverseTransform_(@SuppressWarnings("unused") T2 value) {
throw new RuntimeException("This method was not overridden."); //$NON-NLS-1$
}
// ********** queries **********
/**
* Our constructors accept only a {@link WritablePropertyValueModel<T1>},
* so this cast should be safe.
*/
@SuppressWarnings("unchecked")
protected WritablePropertyValueModel<T1> getValueHolder() {
return (WritablePropertyValueModel<T1>) this.valueHolder;
}
/**
* Our constructors accept only a {@link BidiTransformer<T1, T2>},
* so this cast should be safe.
*/
protected BidiTransformer<T1, T2> getTransformer() {
return (BidiTransformer<T1, T2>) this.transformer;
}
// ********** default bidi transformer **********
/**
* The default bidi transformer will return null if the wrapped value is null.
* If the wrapped value is not null, it is transformed by a subclass
* implementation of {@link #transform_(Object)}.
* The default bidi transformer will also return null if the new value is null.
* If the new value is not null, it is reverse-transformed by a subclass
* implementation of {@link #reverseTransform_(Object)}.
*/
protected class DefaultBidiTransformer
extends DefaultTransformer
implements BidiTransformer<T1, T2>
{
public T1 reverseTransform(T2 value) {
return (value == null) ? null : TransformationWritablePropertyValueModel.this.reverseTransform_(value);
}
}
}
|
