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 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.internal.reflect;

import java.lang.reflect.*;

import java.util.Set;

/** Provides reflective access to the constant pools of classes.

    Currently this is needed to provide reflective access to annotations

    but may be used by other internal subsystems in the future. */

public class ConstantPool {

  // Number of entries in this constant pool (= maximum valid constant pool index)

  public int      getSize()                      { return getSize0            (constantPoolOop);        }

  public Class<?> getClassAt         (int index) { return getClassAt0         (constantPoolOop, index); }

  public Class<?> getClassAtIfLoaded (int index) { return getClassAtIfLoaded0 (constantPoolOop, index); }

  // Returns a class reference index for a method or a field.

  public int getClassRefIndexAt(int index) {

      return getClassRefIndexAt0(constantPoolOop, index);

  }

  // Returns either a Method or Constructor.

  // Static initializers are returned as Method objects.

  public Member   getMethodAt        (int index) { return getMethodAt0        (constantPoolOop, index); }

  public Member   getMethodAtIfLoaded(int index) { return getMethodAtIfLoaded0(constantPoolOop, index); }

  public Field    getFieldAt         (int index) { return getFieldAt0         (constantPoolOop, index); }

  public Field    getFieldAtIfLoaded (int index) { return getFieldAtIfLoaded0 (constantPoolOop, index); }

  // Fetches the class name, member (field, method or interface

  // method) name, and type descriptor as an array of three Strings

  public String[] getMemberRefInfoAt (int index) { return getMemberRefInfoAt0 (constantPoolOop, index); }

  // Returns a name and type reference index for a method, a field or an invokedynamic.

  public int getNameAndTypeRefIndexAt(int index) {

      return getNameAndTypeRefIndexAt0(constantPoolOop, index);

  }

  // Fetches the name and type from name_and_type index as an array of two Strings

  public String[] getNameAndTypeRefInfoAt(int index) {

      return getNameAndTypeRefInfoAt0(constantPoolOop, index);

  }

  public int      getIntAt           (int index) { return getIntAt0           (constantPoolOop, index); }

  public long     getLongAt          (int index) { return getLongAt0          (constantPoolOop, index); }

  public float    getFloatAt         (int index) { return getFloatAt0         (constantPoolOop, index); }

  public double   getDoubleAt        (int index) { return getDoubleAt0        (constantPoolOop, index); }

  public String   getStringAt        (int index) { return getStringAt0        (constantPoolOop, index); }

  public String   getUTF8At          (int index) { return getUTF8At0          (constantPoolOop, index); }

  public Tag getTagAt(int index) {

      return Tag.valueOf(getTagAt0(constantPoolOop, index));

  }

  public static enum Tag {

      UTF8(1),

      INTEGER(3),

      FLOAT(4),

      LONG(5),

      DOUBLE(6),

      CLASS(7),

      STRING(8),

      FIELDREF(9),

      METHODREF(10),

      INTERFACEMETHODREF(11),

      NAMEANDTYPE(12),

      METHODHANDLE(15),

      METHODTYPE(16),

      INVOKEDYNAMIC(18),

      INVALID(0);

      private final int tagCode;

      private Tag(int tagCode) {

          this.tagCode = tagCode;

      }

      private static Tag valueOf(byte v) {

          for (Tag tag : Tag.values()) {

              if (tag.tagCode == v) {

                  return tag;

              }

          }

          throw new IllegalArgumentException("Unknown constant pool tag code " + v);

      }

   }

  //---------------------------------------------------------------------------

  // Internals only below this point

  //

  static {

      Reflection.registerFieldsToFilter(ConstantPool.class, Set.of("constantPoolOop"));

  }

  // HotSpot-internal constant pool object (set by the VM, name known to the VM)

  private Object constantPoolOop;

  private native int      getSize0            (Object constantPoolOop);

  private native Class<?> getClassAt0         (Object constantPoolOop, int index);

  private native Class<?> getClassAtIfLoaded0 (Object constantPoolOop, int index);

  private native int      getClassRefIndexAt0 (Object constantPoolOop, int index);

  private native Member   getMethodAt0        (Object constantPoolOop, int index);

  private native Member   getMethodAtIfLoaded0(Object constantPoolOop, int index);

  private native Field    getFieldAt0         (Object constantPoolOop, int index);

  private native Field    getFieldAtIfLoaded0 (Object constantPoolOop, int index);

  private native String[] getMemberRefInfoAt0 (Object constantPoolOop, int index);

  private native int      getNameAndTypeRefIndexAt0(Object constantPoolOop, int index);

  private native String[] getNameAndTypeRefInfoAt0(Object constantPoolOop, int index);

  private native int      getIntAt0           (Object constantPoolOop, int index);

  private native long     getLongAt0          (Object constantPoolOop, int index);

  private native float    getFloatAt0         (Object constantPoolOop, int index);

  private native double   getDoubleAt0        (Object constantPoolOop, int index);

  private native String   getStringAt0        (Object constantPoolOop, int index);

  private native String   getUTF8At0          (Object constantPoolOop, int index);

  private native byte     getTagAt0           (Object constantPoolOop, int index);

}