1/*
2 * Copyright (c) 2003, 2015, 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 * questions.
24 */
25
26package jdk.internal.reflect;
27
28import java.lang.reflect.*;
29
30/** Provides reflective access to the constant pools of classes.
31    Currently this is needed to provide reflective access to annotations
32    but may be used by other internal subsystems in the future. */
33
34public class ConstantPool {
35  // Number of entries in this constant pool (= maximum valid constant pool index)
36  public int      getSize()                      { return getSize0            (constantPoolOop);        }
37  public Class<?> getClassAt         (int index) { return getClassAt0         (constantPoolOop, index); }
38  public Class<?> getClassAtIfLoaded (int index) { return getClassAtIfLoaded0 (constantPoolOop, index); }
39  // Returns a class reference index for a method or a field.
40  public int getClassRefIndexAt(int index) {
41      return getClassRefIndexAt0(constantPoolOop, index);
42  }
43  // Returns either a Method or Constructor.
44  // Static initializers are returned as Method objects.
45  public Member   getMethodAt        (int index) { return getMethodAt0        (constantPoolOop, index); }
46  public Member   getMethodAtIfLoaded(int index) { return getMethodAtIfLoaded0(constantPoolOop, index); }
47  public Field    getFieldAt         (int index) { return getFieldAt0         (constantPoolOop, index); }
48  public Field    getFieldAtIfLoaded (int index) { return getFieldAtIfLoaded0 (constantPoolOop, index); }
49  // Fetches the class name, member (field, method or interface
50  // method) name, and type descriptor as an array of three Strings
51  public String[] getMemberRefInfoAt (int index) { return getMemberRefInfoAt0 (constantPoolOop, index); }
52  // Returns a name and type reference index for a method, a field or an invokedynamic.
53  public int getNameAndTypeRefIndexAt(int index) {
54      return getNameAndTypeRefIndexAt0(constantPoolOop, index);
55  }
56  // Fetches the name and type from name_and_type index as an array of two Strings
57  public String[] getNameAndTypeRefInfoAt(int index) {
58      return getNameAndTypeRefInfoAt0(constantPoolOop, index);
59  }
60  public int      getIntAt           (int index) { return getIntAt0           (constantPoolOop, index); }
61  public long     getLongAt          (int index) { return getLongAt0          (constantPoolOop, index); }
62  public float    getFloatAt         (int index) { return getFloatAt0         (constantPoolOop, index); }
63  public double   getDoubleAt        (int index) { return getDoubleAt0        (constantPoolOop, index); }
64  public String   getStringAt        (int index) { return getStringAt0        (constantPoolOop, index); }
65  public String   getUTF8At          (int index) { return getUTF8At0          (constantPoolOop, index); }
66  public Tag getTagAt(int index) {
67      return Tag.valueOf(getTagAt0(constantPoolOop, index));
68  }
69
70  public static enum Tag {
71      UTF8(1),
72      INTEGER(3),
73      FLOAT(4),
74      LONG(5),
75      DOUBLE(6),
76      CLASS(7),
77      STRING(8),
78      FIELDREF(9),
79      METHODREF(10),
80      INTERFACEMETHODREF(11),
81      NAMEANDTYPE(12),
82      METHODHANDLE(15),
83      METHODTYPE(16),
84      INVOKEDYNAMIC(18),
85      INVALID(0);
86
87      private final int tagCode;
88
89      private Tag(int tagCode) {
90          this.tagCode = tagCode;
91      }
92
93      private static Tag valueOf(byte v) {
94          for (Tag tag : Tag.values()) {
95              if (tag.tagCode == v) {
96                  return tag;
97              }
98          }
99          throw new IllegalArgumentException("Unknown constant pool tag code " + v);
100      }
101   }
102  //---------------------------------------------------------------------------
103  // Internals only below this point
104  //
105
106  static {
107      Reflection.registerFieldsToFilter(ConstantPool.class, new String[] { "constantPoolOop" });
108  }
109
110  // HotSpot-internal constant pool object (set by the VM, name known to the VM)
111  private Object constantPoolOop;
112
113  private native int      getSize0            (Object constantPoolOop);
114  private native Class<?> getClassAt0         (Object constantPoolOop, int index);
115  private native Class<?> getClassAtIfLoaded0 (Object constantPoolOop, int index);
116  private native int      getClassRefIndexAt0 (Object constantPoolOop, int index);
117  private native Member   getMethodAt0        (Object constantPoolOop, int index);
118  private native Member   getMethodAtIfLoaded0(Object constantPoolOop, int index);
119  private native Field    getFieldAt0         (Object constantPoolOop, int index);
120  private native Field    getFieldAtIfLoaded0 (Object constantPoolOop, int index);
121  private native String[] getMemberRefInfoAt0 (Object constantPoolOop, int index);
122  private native int      getNameAndTypeRefIndexAt0(Object constantPoolOop, int index);
123  private native String[] getNameAndTypeRefInfoAt0(Object constantPoolOop, int index);
124  private native int      getIntAt0           (Object constantPoolOop, int index);
125  private native long     getLongAt0          (Object constantPoolOop, int index);
126  private native float    getFloatAt0         (Object constantPoolOop, int index);
127  private native double   getDoubleAt0        (Object constantPoolOop, int index);
128  private native String   getStringAt0        (Object constantPoolOop, int index);
129  private native String   getUTF8At0          (Object constantPoolOop, int index);
130  private native byte     getTagAt0           (Object constantPoolOop, int index);
131}
132