org.apache.bcel.classfile

Class ConstantPool

public class ConstantPool extends Object implements Cloneable, Node, 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 386056 2006-03-15 11:31:56Z tcurdt $

Author: M. Dahm

See Also: Constant ConstantPoolGen

Field Summary
Constant[]	constant_pool
int	constant_pool_count

Constructor Summary
	ConstantPool(Constant[] constant_pool)
	ConstantPool(DataInputStream file) Read constants from given file stream.

Method Summary
void	accept(Visitor v) Called by objects that are traversing the nodes of the tree implicitely defined by the contents of a Java class.
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.
ConstantPool	copy()
void	dump(DataOutputStream file) Dump constant pool to file stream in binary format.
static String	escape(String str)
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.
Constant[]	getConstantPool()
String	getConstantString(int index, byte tag) Get string from constant pool and bypass the indirection of `ConstantClass' and `ConstantString' objects.
int	getLength()
void	setConstant(int index, Constant constant)
void	setConstantPool(Constant[] constant_pool)
String	toString()

Field Detail

constant_pool

private Constant[] constant_pool

constant_pool_count

private int constant_pool_count

Constructor Detail

ConstantPool

public ConstantPool(Constant[] constant_pool)

Parameters: constant_pool Array of constants

ConstantPool

ConstantPool(DataInputStream file)

Read constants from given file stream.

Parameters: file Input stream

Throws: IOException ClassFormatException

Method Detail

accept

public void accept(Visitor v)

Called by objects that are traversing the nodes of the tree implicitely defined by the contents of a Java class. I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.

Parameters: v Visitor object

constantToString

public String constantToString(Constant c)

Resolve constant to a string representation.

Parameters: c Constant to be printed

Returns: String representation

constantToString

public String constantToString(int index, byte tag)

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

copy

public ConstantPool copy()

Returns: deep copy of this constant pool

dump

public void dump(DataOutputStream file)

Dump constant pool to file stream in binary format.

Parameters: file Output file stream

Throws: IOException

escape

private static final String escape(String str)

getConstant

public Constant getConstant(int index)

Get constant from constant pool.

Parameters: index Index in constant pool

Returns: Constant value

getConstant

public Constant getConstant(int index, byte tag)

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

getConstantPool

public Constant[] getConstantPool()

Returns: Array of constants.

getConstantString

public String getConstantString(int index, byte tag)

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