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;
18:
19: import java.io.DataOutput;
20: import java.io.IOException;
21:
22: /**
23: * This class corresponds to the cp_info structure as defined in
24: * section 4.4 of <i>The Java Virtual Machine Specification</i>.
25: * Subclasses should override the default hashCode and equals methods so
26: * that the ConstantPool will only contain one instance of this constant.
27: *
28: * @author Brian S O'Neill
29: */
30: public abstract class ConstantInfo {
31:
32: public static final int TAG_UTF8 = 1;
33: public static final int TAG_INTEGER = 3;
34: public static final int TAG_FLOAT = 4;
35: public static final int TAG_LONG = 5;
36: public static final int TAG_DOUBLE = 6;
37: public static final int TAG_CLASS = 7;
38: public static final int TAG_STRING = 8;
39: public static final int TAG_FIELD = 9;
40: public static final int TAG_METHOD = 10;
41: public static final int TAG_INTERFACE_METHOD = 11;
42: public static final int TAG_NAME_AND_TYPE = 12;
43:
44: // mIndex is manipulated by ConstantPool
45: int mIndex = -1;
46: private int mTag;
47:
48: protected ConstantInfo(int tag) {
49: mTag = tag;
50: }
51:
52: /**
53: * The index of this constant in the constant pool. Is -1 if the
54: * index has not yet been resolved. Constant pool indexes are resolved
55: * when the constant pool is written out.
56: */
57: public int getIndex() {
58: return mIndex;
59: }
60:
61: protected boolean hasPriority() {
62: return false;
63: }
64:
65: protected int getEntryCount() {
66: return 1;
67: }
68:
69: public void writeTo(DataOutput dout) throws IOException {
70: dout.writeByte(mTag);
71: }
72: }
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