Package org.apache.tools.ant.taskdefs.optional.depend.constantpool

Class ConstantPool

java.lang.Object
org.apache.tools.ant.taskdefs.optional.depend.constantpool.ConstantPool
public class ConstantPool extends Object
The constant pool of a Java class. The constant pool is a collection of constants used in a Java class file. It stores strings, constant values, class names, method names, field names etc.
See Also:

  • Constructor Details

    • ConstantPool

      public ConstantPool()
      Initialise the constant pool.

  • Method Details

    • read

      public void read(DataInputStream classStream) throws IOException
      Read the constant pool from a class input stream.
      Parameters:
      classStream - the DataInputStream of a class file.
      Throws:
      IOException - if there is a problem reading the constant pool from the stream

    • size

      public int size()
      Get the size of the constant pool.
      Returns:
      the size of the constant pool

    • addEntry

      public int addEntry(ConstantPoolEntry entry)
      Add an entry to the constant pool.
      Parameters:
      entry - the new entry to be added to the constant pool.
      Returns:
      the index into the constant pool at which the entry is stored.

    • resolve

      public void resolve()
      Resolve the entries in the constant pool. Resolution of the constant pool involves transforming indexes to other constant pool entries into the actual data for that entry.

    • getEntry

      public ConstantPoolEntry getEntry(int index)
      Get an constant pool entry at a particular index.
      Parameters:
      index - the index into the constant pool.
      Returns:
      the constant pool entry at that index.

    • getUTF8Entry

      public int getUTF8Entry(String value)
      Get the index of a given UTF8 constant pool entry.
      Parameters:
      value - the string value of the UTF8 entry.
      Returns:
      the index at which the given string occurs in the constant pool or -1 if the value does not occur.

    • getClassEntry

      public int getClassEntry(String className)
      Get the index of a given CONSTANT_CLASS entry in the constant pool.
      Parameters:
      className - the name of the class for which the class entry index is required.
      Returns:
      the index at which the given class entry occurs in the constant pool or -1 if the value does not occur.

    • getConstantEntry

      public int getConstantEntry(Object constantValue)
      Get the index of a given constant value entry in the constant pool.
      Parameters:
      constantValue - the constant value for which the index is required.
      Returns:
      the index at which the given value entry occurs in the constant pool or -1 if the value does not occur.

    • getMethodRefEntry

      public int getMethodRefEntry(String methodClassName, String methodName, String methodType)
      Get the index of a given CONSTANT_METHODREF entry in the constant pool.
      Parameters:
      methodClassName - the name of the class which contains the method being referenced.
      methodName - the name of the method being referenced.
      methodType - the type descriptor of the method being referenced.
      Returns:
      the index at which the given method ref entry occurs in the constant pool or -1 if the value does not occur.

    • getInterfaceMethodRefEntry

      public int getInterfaceMethodRefEntry(String interfaceMethodClassName, String interfaceMethodName, String interfaceMethodType)
      Get the index of a given CONSTANT_INTERFACEMETHODREF entry in the constant pool.
      Parameters:
      interfaceMethodClassName - the name of the interface which contains the method being referenced.
      interfaceMethodName - the name of the method being referenced.
      interfaceMethodType - the type descriptor of the method being referenced.
      Returns:
      the index at which the given method ref entry occurs in the constant pool or -1 if the value does not occur.

    • getFieldRefEntry

      public int getFieldRefEntry(String fieldClassName, String fieldName, String fieldType)
      Get the index of a given CONSTANT_FIELDREF entry in the constant pool.
      Parameters:
      fieldClassName - the name of the class which contains the field being referenced.
      fieldName - the name of the field being referenced.
      fieldType - the type descriptor of the field being referenced.
      Returns:
      the index at which the given field ref entry occurs in the constant pool or -1 if the value does not occur.

    • getNameAndTypeEntry

      public int getNameAndTypeEntry(String name, String type)
      Get the index of a given CONSTANT_NAMEANDTYPE entry in the constant pool.
      Parameters:
      name - the name
      type - the type
      Returns:
      the index at which the given NameAndType entry occurs in the constant pool or -1 if the value does not occur.

    • toString

      public String toString()
      Dump the constant pool to a string.
      Overrides:
      toString in class Object
      Returns:
      the constant pool entries as strings