1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.compress.harmony.unpack200.bytecode;
18
19 import java.io.DataOutputStream;
20 import java.io.IOException;
21 import java.util.Objects;
22
23 /**
24 * Abstract superclass for class file attributes
25 */
26 public abstract class Attribute extends ClassFileEntry {
27
28 protected final CPUTF8 attributeName;
29
30 private int attributeNameIndex;
31
32 public Attribute(final CPUTF8 attributeName) {
33 this.attributeName = attributeName;
34 }
35
36 @Override
37 protected void doWrite(final DataOutputStream dos) throws IOException {
38 dos.writeShort(attributeNameIndex);
39 dos.writeInt(getLength());
40 writeBody(dos);
41 }
42
43 @Override
44 public boolean equals(final Object obj) {
45 if (this == obj) {
46 return true;
47 }
48 if (obj == null) {
49 return false;
50 }
51 if (this.getClass() != obj.getClass()) {
52 return false;
53 }
54 final Attribute other = (Attribute) obj;
55 return Objects.equals(attributeName, other.attributeName);
56 }
57
58 protected CPUTF8 getAttributeName() {
59 return attributeName;
60 }
61
62 protected abstract int getLength();
63
64 /**
65 * Answer the length of the receiver including its header (the u2 for the attribute name and the u4 for the attribute length). This is relevant when
66 * attributes are nested within other attributes - the outer attribute needs to take the inner attribute headers into account when calculating its length.
67 *
68 * @return int adjusted length
69 */
70 protected int getLengthIncludingHeader() {
71 return getLength() + 2 + 4;
72 }
73
74 @Override
75 protected ClassFileEntry[] getNestedClassFileEntries() {
76 return new ClassFileEntry[] { getAttributeName() };
77 }
78
79 /**
80 * Answer true if the receiver needs to have BCI renumbering applied to it; otherwise answer false.
81 *
82 * @return boolean BCI renumbering required
83 */
84 public boolean hasBCIRenumbering() {
85 return false;
86 }
87
88 @Override
89 public int hashCode() {
90 return Objects.hash(attributeName);
91 }
92
93 /**
94 * Answer true if the receiver is a source file attribute (which gets special handling when the class is built); otherwise answer false.
95 *
96 * @return boolean source file attribute
97 */
98 public boolean isSourceFileAttribute() {
99 return false;
100 }
101
102 @Override
103 protected void resolve(final ClassConstantPool pool) {
104 super.resolve(pool);
105 attributeNameIndex = pool.indexOf(attributeName);
106 }
107
108 protected abstract void writeBody(DataOutputStream dos) throws IOException;
109
110 }