1 /*
2 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 package sun.jvm.hotspot.oops;
26
27 import java.io.*;
28
29 import sun.jvm.hotspot.runtime.*;
30
31 // Super class for all fields in an object
32 public class Field {
33
34 Field(FieldIdentifier id, long offset, boolean isVMField) {
35 this.offset = offset;
36 this.id = id;
37 this.isVMField = isVMField;
38 }
39
40 /** Constructor for fields that are named in an InstanceKlass's
41 fields array (i.e., named, non-VM fields) */
42 Field(InstanceKlass holder, int fieldArrayIndex) {
43 this.holder = holder;
44 this.fieldArrayIndex = fieldArrayIndex;
45
46 ConstantPool cp = holder.getConstants();
47 TypeArray fields = holder.getFields();
48 short access = fields.getShortAt(fieldArrayIndex + InstanceKlass.ACCESS_FLAGS_OFFSET);
49 short nameIndex = fields.getShortAt(fieldArrayIndex + InstanceKlass.NAME_INDEX_OFFSET);
50 short signatureIndex = fields.getShortAt(fieldArrayIndex + InstanceKlass.SIGNATURE_INDEX_OFFSET);
51 initialValueIndex = fields.getShortAt(fieldArrayIndex + InstanceKlass.INITVAL_INDEX_OFFSET);
52 offset = VM.getVM().buildIntFromShorts(fields.getShortAt(fieldArrayIndex + InstanceKlass.LOW_OFFSET),
53 fields.getShortAt(fieldArrayIndex + InstanceKlass.HIGH_OFFSET));
54 short genericSignatureIndex = fields.getShortAt(fieldArrayIndex + InstanceKlass.GENERIC_SIGNATURE_INDEX_OFFSET);
55 Symbol name = cp.getSymbolAt(nameIndex);
56 id = new NamedFieldIdentifier(name.asString());
57 signature = cp.getSymbolAt(signatureIndex);
58 if (genericSignatureIndex != 0) {
59 genericSignature = cp.getSymbolAt(genericSignatureIndex);
60 } else {
61 genericSignature = null;
62 }
63
64 fieldType = new FieldType(signature);
65 accessFlags = new AccessFlags(access);
66 }
67
68 private long offset;
69 private FieldIdentifier id;
70 private boolean isVMField;
71 // Java fields only
72 private InstanceKlass holder;
73 private FieldType fieldType;
74 private Symbol signature;
75 private Symbol genericSignature;
76 private AccessFlags accessFlags;
77 private int fieldArrayIndex;
78 private int initialValueIndex;
79
80 /** Returns the byte offset of the field within the object or klass */
81 public long getOffset() { return offset; }
82
83 /** Returns the identifier of the field */
84 public FieldIdentifier getID() { return id; }
85
86 /** Indicates whether this is a VM field */
87 public boolean isVMField() { return isVMField; }
88
89 /** Indicates whether this is a named field */
90 public boolean isNamedField() { return (id instanceof NamedFieldIdentifier); }
91
92 public void printOn(PrintStream tty) {
93 getID().printOn(tty);
94 tty.print(" {" + getOffset() + "} :");
95 }
96
97 /** (Named, non-VM fields only) Returns the InstanceKlass containing
98 this (static or non-static) field. */
99 public InstanceKlass getFieldHolder() {
100 return holder;
101 }
102
103 /** (Named, non-VM fields only) Returns the index in the fields
104 TypeArray for this field. Equivalent to the "index" in the VM's
105 fieldDescriptors. */
106 public int getFieldArrayIndex() {
107 return fieldArrayIndex;
108 }
109
110 /** (Named, non-VM fields only) Retrieves the access flags. */
111 public long getAccessFlags() { return accessFlags.getValue(); }
112 public AccessFlags getAccessFlagsObj() { return accessFlags; }
113
114 /** (Named, non-VM fields only) Returns the type of this field. */
115 public FieldType getFieldType() { return fieldType; }
116
117 /** (Named, non-VM fields only) Returns the signature of this
118 field. */
119 public Symbol getSignature() { return signature; }
120 public Symbol getGenericSignature() { return genericSignature; }
121
122 //
123 // Following acccessors are for named, non-VM fields only
124 //
125 public boolean isPublic() { return accessFlags.isPublic(); }
126 public boolean isPrivate() { return accessFlags.isPrivate(); }
127 public boolean isProtected() { return accessFlags.isProtected(); }
128 public boolean isPackagePrivate() { return !isPublic() && !isPrivate() && !isProtected(); }
129
130 public boolean isStatic() { return accessFlags.isStatic(); }
131 public boolean isFinal() { return accessFlags.isFinal(); }
132 public boolean isVolatile() { return accessFlags.isVolatile(); }
133 public boolean isTransient() { return accessFlags.isTransient(); }
134
135 public boolean isSynthetic() { return accessFlags.isSynthetic(); }
136 public boolean isEnumConstant() { return accessFlags.isEnum(); }
137
138 public boolean hasInitialValue() { return initialValueIndex != 0; }
139
140 public boolean equals(Object obj) {
141 if (obj == null) {
142 return false;
143 }
144
145 if (! (obj instanceof Field)) {
146 return false;
147 }
148
149 Field other = (Field) obj;
150 return this.getFieldHolder().equals(other.getFieldHolder()) &&
151 this.getID().equals(other.getID());
152 }
153
154 public int hashCode() {
155 return getFieldHolder().hashCode() ^ getID().hashCode();
156 }
157 }