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
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.reflect;
  27 
  28 import 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 
  34 public 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 either a Method or Constructor.
  40   // Static initializers are returned as Method objects.
  41   public Member   getMethodAt        (int index) { return getMethodAt0        (constantPoolOop, index); }
  42   public Member   getMethodAtIfLoaded(int index) { return getMethodAtIfLoaded0(constantPoolOop, index); }
  43   public Field    getFieldAt         (int index) { return getFieldAt0         (constantPoolOop, index); }
  44   public Field    getFieldAtIfLoaded (int index) { return getFieldAtIfLoaded0 (constantPoolOop, index); }
  45   // Fetches the class name, member (field, method or interface
  46   // method) name, and type descriptor as an array of three Strings
  47   public String[] getMemberRefInfoAt (int index) { return getMemberRefInfoAt0 (constantPoolOop, index); }
  48   // Fetches the name and type from name_and_type index as an array of two Strings
  49   public String[] getNameAndTypeRefInfoAt
  50                                      (int index) { return getNameAndTypeRefInfoAt0 (constantPoolOop, index); }
  51   // Fetches the invokedynamic name and type descriptor as an array of two Strings
  52   public String[] getInvokedynamicRefInfoAt
  53                                      (int index) { return getInvokedynamicRefInfoAt0 (constantPoolOop, index); }
  54   public int      getIntAt           (int index) { return getIntAt0           (constantPoolOop, index); }
  55   public long     getLongAt          (int index) { return getLongAt0          (constantPoolOop, index); }
  56   public float    getFloatAt         (int index) { return getFloatAt0         (constantPoolOop, index); }
  57   public double   getDoubleAt        (int index) { return getDoubleAt0        (constantPoolOop, index); }
  58   public String   getStringAt        (int index) { return getStringAt0        (constantPoolOop, index); }
  59   public String   getUTF8At          (int index) { return getUTF8At0          (constantPoolOop, index); }
  60   public Tag      getTagAt           (int index) { return Tag.valueOf(
  61                                                           getTagAt0           (constantPoolOop, index));}
  62 
  63   public static enum Tag {
  64       UTF8,
  65       INTEGER,
  66       FLOAT,
  67       LONG,
  68       DOUBLE,
  69       CLASS,
  70       STRING,
  71       FIELDREF,
  72       METHODREF,
  73       INTERFACEMETHODREF,
  74       NAMEANDTYPE,
  75       METHODHANDLE,
  76       METHODTYPE,
  77       INVOKEDYNAMIC,
  78       INVALID,
  79       UNRESOLVED_CLASS,
  80       CLASS_INDEX,
  81       STRING_INDEX,
  82       UNRESOLVED_CLASS_IN_ERROR,
  83       METHODHANDLE_IN_ERROR,
  84       METHODTYPE_IN_ERROR;
  85 
  86       private static Tag valueOf(byte v) {
  87           switch (v) {
  88               case   0: return INVALID;
  89               case   1: return UTF8;
  90               case   3: return INTEGER;
  91               case   4: return FLOAT;
  92               case   5: return LONG;
  93               case   6: return DOUBLE;
  94               case   7: return CLASS;
  95               case   8: return STRING;
  96               case   9: return FIELDREF;
  97               case  10: return METHODREF;
  98               case  11: return INTERFACEMETHODREF;
  99               case  12: return NAMEANDTYPE;
 100               case  15: return METHODHANDLE;
 101               case  16: return METHODTYPE;
 102               case  18: return INVOKEDYNAMIC;
 103               // The tags 100 - 105 are hotspot specific ones
 104               // (not from JVM spec) used in constantTag.hpp
 105               case 100: return UNRESOLVED_CLASS;
 106               case 101: return CLASS_INDEX;
 107               case 102: return STRING_INDEX;
 108               case 103: return UNRESOLVED_CLASS_IN_ERROR;
 109               case 104: return METHODHANDLE_IN_ERROR;
 110               case 105: return METHODTYPE_IN_ERROR;
 111               default:
 112                   throw new IllegalArgumentException("Unknown constant pool tag " + v);
 113           }
 114       }
 115    }
 116   //---------------------------------------------------------------------------
 117   // Internals only below this point
 118   //
 119 
 120   static {
 121       Reflection.registerFieldsToFilter(ConstantPool.class, new String[] { "constantPoolOop" });
 122   }
 123 
 124   // HotSpot-internal constant pool object (set by the VM, name known to the VM)
 125   private Object constantPoolOop;
 126 
 127   private native int      getSize0            (Object constantPoolOop);
 128   private native Class<?> getClassAt0         (Object constantPoolOop, int index);
 129   private native Class<?> getClassAtIfLoaded0 (Object constantPoolOop, int index);
 130   private native Member   getMethodAt0        (Object constantPoolOop, int index);
 131   private native Member   getMethodAtIfLoaded0(Object constantPoolOop, int index);
 132   private native Field    getFieldAt0         (Object constantPoolOop, int index);
 133   private native Field    getFieldAtIfLoaded0 (Object constantPoolOop, int index);
 134   private native String[] getMemberRefInfoAt0 (Object constantPoolOop, int index);
 135   private native String[] getNameAndTypeRefInfoAt0
 136                                               (Object constantPoolOop, int index);
 137   private native String[] getInvokedynamicRefInfoAt0
 138                                               (Object constantPoolOop, int index);
 139   private native int      getIntAt0           (Object constantPoolOop, int index);
 140   private native long     getLongAt0          (Object constantPoolOop, int index);
 141   private native float    getFloatAt0         (Object constantPoolOop, int index);
 142   private native double   getDoubleAt0        (Object constantPoolOop, int index);
 143   private native String   getStringAt0        (Object constantPoolOop, int index);
 144   private native String   getUTF8At0          (Object constantPoolOop, int index);
 145   private native byte     getTagAt0           (Object constantPoolOop, int index);
 146 }