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 package sun.invoke.anon;

 /**

  * A visitor called by {@link ConstantPoolParser#parse(ConstantPoolVisitor)}

  * when a constant pool entry is parsed.

  * <p>

  * A visit* method is called when a constant pool entry is parsed.

  * The first argument is always the constant pool index.

  * The second argument is always the constant pool tag,

  * even for methods like {@link #visitUTF8(int, byte, String)} which only apply to one tag.

  * String arguments refer to Utf8 or NameAndType entries declared elsewhere,

  * and are always accompanied by the indexes of those entries.

  * <p>

  * The order of the calls to the visit* methods is not necessarily related

  * to the order of the entries in the constant pool.

  * If one entry has a reference to another entry, the latter (lower-level)

  * entry will be visited first.

  * <p>

  * The following table shows the relation between constant pool entry

  * types and the corresponding visit* methods:

  *

  * <table border=1 cellpadding=5 summary="constant pool visitor methods">

  * <tr><th>Tag(s)</th><th>Method</th></tr>

  * <tr>

  *   <td>{@link #CONSTANT_Utf8}</td>

  *   <td>{@link #visitUTF8(int, byte, String)}</td>

  * </tr><tr>

  *   <td>{@link #CONSTANT_Integer}, {@link #CONSTANT_Float},

  *       {@link #CONSTANT_Long}, {@link #CONSTANT_Double}</td>

  *   <td>{@link #visitConstantValue(int, byte, Object)}</td>

  * </tr><tr>

  *   <td>{@link #CONSTANT_String}, {@link #CONSTANT_Class}</td>

  *   <td>{@link #visitConstantString(int, byte, String, int)}</td>

  * </tr><tr>

  *   <td>{@link #CONSTANT_NameAndType}</td>

  *   <td>{@link #visitDescriptor(int, byte, String, String, int, int)}</td>

  * </tr><tr>

  *   <td>{@link #CONSTANT_Fieldref},

  *       {@link #CONSTANT_Methodref},

  *       {@link #CONSTANT_InterfaceMethodref}</td>

  *   <td>{@link #visitMemberRef(int, byte, String, String, String, int, int)}</td>

  * </tr>

  * </table>

  *

  * @see ConstantPoolPatch

  * @author Remi Forax

  * @author jrose

  */

 public class ConstantPoolVisitor {

   /** Called each time an UTF8 constant pool entry is found.

    * @param index the constant pool index

    * @param tag always {@link #CONSTANT_Utf8}

    * @param utf8 string encoded in modified UTF-8 format passed as a {@code String}

    *

    * @see ConstantPoolPatch#putUTF8(int, String)

    */

   public void visitUTF8(int index, byte tag, String utf8) {

     // do nothing

   }

   /** Called for each constant pool entry that encodes an integer,

    *  a float, a long, or a double.

    *  Constant strings and classes are not managed by this method but

    *  by {@link #visitConstantString(int, byte, String, int)}.

    *

    * @param index the constant pool index

    * @param tag one of {@link #CONSTANT_Integer},

    *            {@link #CONSTANT_Float},

    *            {@link #CONSTANT_Long},

    *            or {@link #CONSTANT_Double}

    * @param value encoded value

    *

    * @see ConstantPoolPatch#putConstantValue(int, Object)

    */

   public void visitConstantValue(int index, byte tag, Object value) {

     // do nothing

   }

   /** Called for each constant pool entry that encodes a string or a class.

    * @param index the constant pool index

    * @param tag one of {@link #CONSTANT_String},

    *            {@link #CONSTANT_Class},

    * @param name string body or class name (using dot separator)

    * @param nameIndex the index of the Utf8 string for the name

    *

    * @see ConstantPoolPatch#putConstantValue(int, byte, Object)

    */

   public void visitConstantString(int index, byte tag,

                                   String name, int nameIndex) {

     // do nothing

   }

   /** Called for each constant pool entry that encodes a name and type.

    * @param index the constant pool index

    * @param tag always {@link #CONSTANT_NameAndType}

    * @param memberName a field or method name

    * @param signature the member signature

    * @param memberNameIndex index of the Utf8 string for the member name

    * @param signatureIndex index of the Utf8 string for the signature

    *

    * @see ConstantPoolPatch#putDescriptor(int, String, String)

    */

   public void visitDescriptor(int index, byte tag,

                               String memberName, String signature,

                               int memberNameIndex, int signatureIndex) {

     // do nothing

   }

   /** Called for each constant pool entry that encodes a field or method.

    * @param index the constant pool index

    * @param tag one of {@link #CONSTANT_Fieldref},

    *            or {@link #CONSTANT_Methodref},

    *            or {@link #CONSTANT_InterfaceMethodref}

    * @param className the class name (using dot separator)

    * @param memberName name of the field or method

    * @param signature the field or method signature

    * @param classNameIndex index of the Utf8 string for the class name

    * @param descriptorIndex index of the NameAndType descriptor constant

    *

    * @see ConstantPoolPatch#putMemberRef(int, byte, String, String, String)

    */

   public void visitMemberRef(int index, byte tag,

                              String className, String memberName, String signature,

                              int classNameIndex, int descriptorIndex) {

     // do nothing

   }

     public static final byte

       CONSTANT_None = 0,

       CONSTANT_Utf8 = 1,

       //CONSTANT_Unicode = 2,               /* unused */

       CONSTANT_Integer = 3,

       CONSTANT_Float = 4,

       CONSTANT_Long = 5,

       CONSTANT_Double = 6,

       CONSTANT_Class = 7,

       CONSTANT_String = 8,

       CONSTANT_Fieldref = 9,

       CONSTANT_Methodref = 10,

       CONSTANT_InterfaceMethodref = 11,

       CONSTANT_NameAndType = 12;

     private static String[] TAG_NAMES = {

         "Empty",

         "Utf8",

         null, //"Unicode",

         "Integer",

         "Float",

         "Long",

         "Double",

         "Class",

         "String",

         "Fieldref",

         "Methodref",

         "InterfaceMethodref",

         "NameAndType"

     };

     public static String tagName(byte tag) {

         String name = null;

         if ((tag & 0xFF) < TAG_NAMES.length)

             name = TAG_NAMES[tag];

         if (name == null)

             name = "Unknown#"+(tag&0xFF);

         return name;

     }

 }