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:

• The Java Virtual Machine Specification

Constructor Summary

Constructors

Constructor	Description
ConstantPool()	Initialise the constant pool.

Method Summary

Modifier and Type	Method	Description
int	addEntry(ConstantPoolEntry entry)	Add an entry to the constant pool.
int	getClassEntry(String className)	Get the index of a given CONSTANT_CLASS entry in the constant pool.
int	getConstantEntry(Object constantValue)	Get the index of a given constant value entry in the constant pool.
ConstantPoolEntry	getEntry(int index)	Get an constant pool entry at a particular index.
int	getFieldRefEntry(String fieldClassName, String fieldName, String fieldType)	Get the index of a given CONSTANT_FIELDREF entry in the constant pool.
int	getInterfaceMethodRefEntry(String interfaceMethodClassName, String interfaceMethodName, String interfaceMethodType)	Get the index of a given CONSTANT_INTERFACEMETHODREF entry in the constant pool.
int	getMethodRefEntry(String methodClassName, String methodName, String methodType)	Get the index of a given CONSTANT_METHODREF entry in the constant pool.
int	getNameAndTypeEntry(String name, String type)	Get the index of a given CONSTANT_NAMEANDTYPE entry in the constant pool.
int	getUTF8Entry(String value)	Get the index of a given UTF8 constant pool entry.
void	read(DataInputStream classStream)	Read the constant pool from a class input stream.
void	resolve()	Resolve the entries in the constant pool.
int	size()	Get the size of the constant pool.
String	toString()	Dump the constant pool to a string.

Methods inherited from class java.lang.Object

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

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