01: /*
02: * Copyright 2004 Brian S O'Neill
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16:
17: package org.cojen.classfile.attribute;
18:
19: import java.io.DataInput;
20: import java.io.DataOutput;
21: import java.io.IOException;
22: import org.cojen.classfile.Attribute;
23: import org.cojen.classfile.ConstantInfo;
24: import org.cojen.classfile.ConstantPool;
25:
26: /**
27: * This class corresponds to the ConstantValue_attribute structure as defined
28: * in section 4.7.3 of <i>The Java Virtual Machine Specification</i>.
29: *
30: * @author Brian S O'Neill
31: */
32: public class ConstantValueAttr extends Attribute {
33:
34: private final ConstantInfo mConstant;
35:
36: public ConstantValueAttr(ConstantPool cp, ConstantInfo constant) {
37: super (cp, CONSTANT_VALUE);
38: mConstant = constant;
39: }
40:
41: public ConstantValueAttr(ConstantPool cp, String name,
42: ConstantInfo constant) {
43: super (cp, name);
44: mConstant = constant;
45: }
46:
47: public ConstantValueAttr(ConstantPool cp, String name, int length,
48: DataInput din) throws IOException {
49: super (cp, name);
50: int index = din.readUnsignedShort();
51: if ((length -= 2) > 0) {
52: din.skipBytes(length);
53: }
54: mConstant = cp.getConstant(index);
55: }
56:
57: public ConstantInfo getConstant() {
58: return mConstant;
59: }
60:
61: public int getLength() {
62: return 2;
63: }
64:
65: public void writeDataTo(DataOutput dout) throws IOException {
66: dout.writeShort(mConstant.getIndex());
67: }
68: }
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