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Java > Open Source Codes > proguard > evaluation > value > ValueFactory


1 /*
2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
3  * of Java bytecode.
4  *
5  * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu)
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  *
12  * This program is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with this program; if not, write to the Free Software Foundation, Inc.,
19  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 package proguard.evaluation.value;
22
23 import proguard.classfile.*;
24 import proguard.classfile.util.ClassUtil;
25
26 /**
27  * This class provides methods to create and reuse Value objects.
28  *
29  * @author Eric Lafortune
30  */
31 public class ValueFactory
32 {
33     // Shared copies of Value objects, to avoid creating a lot of objects.
34 static final IntegerValue INTEGER_VALUE = new IntegerValue();
35     static final LongValue LONG_VALUE = new LongValue();
36     static final FloatValue FLOAT_VALUE = new FloatValue();
37     static final DoubleValue DOUBLE_VALUE = new DoubleValue();
38
39     static final ReferenceValue REFERENCE_VALUE_NULL = new ReferenceValue(null, null, true);
40     static final ReferenceValue REFERENCE_VALUE_JAVA_LANG_OBJECT_MAYBE_NULL = new ReferenceValue(ClassConstants.INTERNAL_NAME_JAVA_LANG_OBJECT, null, true);
41     static final ReferenceValue REFERENCE_VALUE_JAVA_LANG_OBJECT_NOT_NULL = new ReferenceValue(ClassConstants.INTERNAL_NAME_JAVA_LANG_OBJECT, null, false);
42
43
44     /**
45      * Creates a new undefined Value of the given type.
46      * The type must be a fully specified internal type for primitives, classes,
47      * or arrays.
48      */
49     public Value createValue(String JavaDoc type, Clazz referencedClass, boolean mayBeNull)
50     {
51         switch (type.charAt(0))
52         {
53             case ClassConstants.INTERNAL_TYPE_VOID: return null;
54             case ClassConstants.INTERNAL_TYPE_BOOLEAN:
55             case ClassConstants.INTERNAL_TYPE_BYTE:
56             case ClassConstants.INTERNAL_TYPE_CHAR:
57             case ClassConstants.INTERNAL_TYPE_SHORT:
58             case ClassConstants.INTERNAL_TYPE_INT: return INTEGER_VALUE;
59             case ClassConstants.INTERNAL_TYPE_LONG: return LONG_VALUE;
60             case ClassConstants.INTERNAL_TYPE_FLOAT: return FLOAT_VALUE;
61             case ClassConstants.INTERNAL_TYPE_DOUBLE: return DOUBLE_VALUE;
62             default: return createReferenceValue(ClassUtil.isInternalArrayType(type) ?
63                                                                                        type :
64                                                                                        ClassUtil.internalClassNameFromClassType(type),
65                                                                                    referencedClass,
66                                                                                    mayBeNull);
67         }
68     }
69
70     /**
71      * Creates a new IntegerValue with an undefined value.
72      */
73     public IntegerValue createIntegerValue()
74     {
75         return INTEGER_VALUE;
76     }
77
78     /**
79      * Creates a new IntegerValue with a given specific value.
80      */
81     public IntegerValue createIntegerValue(int value)
82     {
83         return createIntegerValue();
84     }
85
86
87     /**
88      * Creates a new LongValue with an undefined value.
89      */
90     public LongValue createLongValue()
91     {
92         return LONG_VALUE;
93     }
94
95     /**
96      * Creates a new LongValue with a given specific value.
97      */
98     public LongValue createLongValue(long value)
99     {
100         return createLongValue();
101     }
102
103
104     /**
105      * Creates a new FloatValue with an undefined value.
106      */
107     public FloatValue createFloatValue()
108     {
109         return FLOAT_VALUE;
110     }
111
112     /**
113      * Creates a new FloatValue with a given specific value.
114      */
115     public FloatValue createFloatValue(float value)
116     {
117         return createFloatValue();
118     }
119
120
121     /**
122      * Creates a new DoubleValue with an undefined value.
123      */
124     public DoubleValue createDoubleValue()
125     {
126         return DOUBLE_VALUE;
127     }
128
129     /**
130      * Creates a new DoubleValue with a given specific value.
131      */
132     public DoubleValue createDoubleValue(double value)
133     {
134         return createDoubleValue();
135     }
136
137
138     /**
139      * Creates a new ReferenceValue that represents <code>null</code>.
140      */
141     public ReferenceValue createReferenceValueNull()
142     {
143         return REFERENCE_VALUE_NULL;
144     }
145
146
147     /**
148      * Creates a new ReferenceValue of the given type. The type must be an
149      * internal class name or an array type. If the type is <code>null</code>,
150      * the ReferenceValue represents <code>null</code>.
151      */
152     public ReferenceValue createReferenceValue(String JavaDoc type,
153                                                Clazz referencedClass,
154                                                boolean mayBeNull)
155     {
156         return type == null ? REFERENCE_VALUE_NULL :
157                !type.equals(ClassConstants.INTERNAL_NAME_JAVA_LANG_OBJECT) ? new ReferenceValue(type, referencedClass, mayBeNull) :
158                mayBeNull ? REFERENCE_VALUE_JAVA_LANG_OBJECT_MAYBE_NULL :
159                                                                              REFERENCE_VALUE_JAVA_LANG_OBJECT_NOT_NULL;
160     }
161
162
163     /**
164      * Creates a new ReferenceValue for arrays of the given type and length.
165      * The type must be a fully specified internal type for primitives, classes,
166      * or arrays.
167      */
168     public ReferenceValue createArrayReferenceValue(String JavaDoc type,
169                                                     Clazz referencedClass,
170                                                     IntegerValue arrayLength)
171     {
172         return createArrayReferenceValue(type,
173                                          referencedClass,
174                                          arrayLength,
175                                          createValue(type, referencedClass, false));
176     }
177
178
179     /**
180      * Creates a new ReferenceValue for arrays of the given type and length,
181      * containing the given element. The type must be a fully specified internal
182      * type for primitives, classes, or arrays.
183      */
184     public ReferenceValue createArrayReferenceValue(String JavaDoc type,
185                                                     Clazz referencedClass,
186                                                     IntegerValue arrayLength,
187                                                     Value elementValue)
188     {
189         return createReferenceValue(ClassConstants.INTERNAL_TYPE_ARRAY + type,
190                                     referencedClass,
191                                     false);
192     }
193 }
194
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