org.apache.tomcat.util.bcel.classfile
Class ConstantPool

java.lang.Object
  org.apache.tomcat.util.bcel.classfile.ConstantPool

All Implemented Interfaces:

Serializable, Cloneable

public class ConstantPool
extends Object
implements Cloneable, Serializable

This class represents the constant pool, i.e., a table of constants, of a parsed classfile. It may contain null references, due to the JVM specification that skips an entry after an 8-byte constant (double, long) entry. Those interested in generating constant pools programatically should see ConstantPoolGen.

Version:

$Id: ConstantPool.java 1181133 2011-10-10 18:49:14Z markt $

Author:

M. Dahm

See Also:

Constant, Serialized Form

Method Summary

String	constantToString(Constant c) Resolve constant to a string representation.
String	constantToString(int index, byte tag) Retrieve constant at `index' from constant pool and resolve it to a string representation.
Constant	getConstant(int index) Get constant from constant pool.
Constant	getConstant(int index, byte tag) Get constant from constant pool and check whether it has the expected type.
String	getConstantString(int index, byte tag) Get string from constant pool and bypass the indirection of `ConstantClass' and `ConstantString' objects.
int	getLength()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

constantToString

public String constantToString(Constant c)
                        throws ClassFormatException

Resolve constant to a string representation.

Parameters:

c - Constant to be printed

Returns:

String representation

Throws:

ClassFormatException

constantToString

public String constantToString(int index,
                               byte tag)
                        throws ClassFormatException

Retrieve constant at `index' from constant pool and resolve it to a string representation.

Parameters:

index - of constant in constant pool

tag - expected type

Returns:

String representation

Throws:

ClassFormatException

getConstant

public Constant getConstant(int index)

Get constant from constant pool.

Parameters:

index - Index in constant pool

Returns:

Constant value

See Also:

Constant

getConstant

public Constant getConstant(int index,
                            byte tag)
                     throws ClassFormatException

Get constant from constant pool and check whether it has the expected type.

Parameters:

index - Index in constant pool

tag - Tag of expected constant, i.e., its type

Returns:

Constant value

Throws:

ClassFormatException

See Also:

Constant

getConstantString

public String getConstantString(int index,
                                byte tag)
                         throws ClassFormatException

Get string from constant pool and bypass the indirection of `ConstantClass' and `ConstantString' objects. I.e. these classes have an index field that points to another entry of the constant pool of type `ConstantUtf8' which contains the real data.

Parameters:

index - Index in constant pool

tag - Tag of expected constant, either ConstantClass or ConstantString

Returns:

Contents of string reference

Throws:

ClassFormatException

See Also:

ConstantClass, ConstantString

getLength

public int getLength()

Returns:

Length of constant pool.

toString

public String toString()

Overrides:

toString in class Object

Returns:

String representation.