com.vladium.jcd.cls
Class ConstantCollection

java.lang.Object
  com.vladium.jcd.cls.ConstantCollection

All Implemented Interfaces:

IConstantCollection, IClassFormatOutput, java.lang.Cloneable

final class ConstantCollection
extends java.lang.Object
implements IConstantCollection

Author:

(C) 2001, Vladimir Roubtsov

Nested Class Summary

private static class

ConstantCollection.ConstantIterator

Nested classes/interfaces inherited from interface com.vladium.jcd.cls.IConstantCollection

IConstantCollection.IConstantComparator, IConstantCollection.IConstantIterator

Field Summary

private ObjectIntMap	m_CONSTANT_Utf8_index
private java.util.List	m_constants
private int	m_size

Constructor Summary

ConstantCollection(int capacity)

Method Summary

void	accept(IClassDefVisitor visitor, java.lang.Object ctx)
int	add(CONSTANT_info constant) Appends 'constant' to the end of the collection.
java.lang.Object	clone() Performs a deep copy.
int	find(int type, IConstantCollection.IConstantComparator comparator) Searches the pool for a matching constant of given type with equality semantics expressed by 'comparator'.
int	findCONSTANT_Utf8(java.lang.String value) Convenience method that can lookup CONSTANT_Utf8 entries in O(1) time on average.
CONSTANT_info	get(int index) Returns a CONSTANT_info at a given pool index.
private ObjectIntMap	getCONSTANT_Utf8_index()
IConstantCollection.IConstantIterator	iterator() Returns a fail-fast iterator over all valid entries in the pool.
CONSTANT_info	set(int index, CONSTANT_info constant) Replaces an existing constant pool entry.
int	size() Returns the number of CONSTANT_info entries in this collection.
void	writeInClassFormat(UDataOutputStream out)

Methods inherited from class java.lang.Object

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

Field Detail

m_constants

private java.util.List m_constants

m_size

private int m_size

m_CONSTANT_Utf8_index

private transient ObjectIntMap m_CONSTANT_Utf8_index

Constructor Detail

ConstantCollection

ConstantCollection(int capacity)

Method Detail

get

public CONSTANT_info get(int index)

Description copied from interface: IConstantCollection

Returns a CONSTANT_info at a given pool index. Note that 'index' is 1-based [the way an index would be embedded in bytecode instructions]. Note that because CONSTANT_Long and CONSTANT_Double entries occupy two consequitive index slots certain index values inside the valid range can be invalid; use IConstantCollection.iterator() to iterate only over valid entries in a transparent fashion.

Specified by:

get in interface IConstantCollection

Parameters:

index - constant pool index [must be in [1, size()] range]

Returns:

CONSTANT_info constant pool entry at this index [never null]

iterator

public IConstantCollection.IConstantIterator iterator()

Description copied from interface: IConstantCollection

Returns a fail-fast iterator over all valid entries in the pool. The resulting object would be invalidated by simultaneous mutation to the underlying collection pool.

Specified by:

iterator in interface IConstantCollection

Returns:

IConstantIterator iterator over all entries in the collection [never null]

find

public int find(int type,
                IConstantCollection.IConstantComparator comparator)

Description copied from interface: IConstantCollection

Searches the pool for a matching constant of given type with equality semantics expressed by 'comparator'. This method guarantees that when comparator.equals(c) is called c.type() is 'type'. The cost is O(pool size). When multiple matches exist, the location of the first one found will be returned (chosen in some indeterministic way).

Specified by:

find in interface IConstantCollection

Parameters:

type - type of constants to filter by [not validated]

comparator - [may not be null]

Returns:

index of the first found entry [-1 if not found]

findCONSTANT_Utf8

public int findCONSTANT_Utf8(java.lang.String value)

Description copied from interface: IConstantCollection

Convenience method that can lookup CONSTANT_Utf8 entries in O(1) time on average. Note that .class format does not guarantee that all such entries are not duplicated in the pool. When multiple matches exist, the location of the first one found will be returned (chosen in some indeterministic way).

Specified by:

findCONSTANT_Utf8 in interface IConstantCollection

Parameters:

value - string value on which to match [may not be null]

Returns:

index of the first found entry [-1 if not found]

size

public int size()

Description copied from interface: IConstantCollection

Returns the number of CONSTANT_info entries in this collection.

Specified by:

size in interface IConstantCollection

Returns:

the number of constants in this pool [can be 0]

clone

public java.lang.Object clone()

Performs a deep copy.

Specified by:

clone in interface IConstantCollection

Overrides:

clone in class java.lang.Object

writeInClassFormat

public void writeInClassFormat(UDataOutputStream out)
                        throws java.io.IOException

Specified by:

writeInClassFormat in interface IClassFormatOutput

Throws:

java.io.IOException

accept

public void accept(IClassDefVisitor visitor,
                   java.lang.Object ctx)

Specified by:

accept in interface IConstantCollection

set

public CONSTANT_info set(int index,
                         CONSTANT_info constant)

Description copied from interface: IConstantCollection

Replaces an existing constant pool entry. A replacement can be made only for a constant of the same width as the constant currently occupying the slot.

Specified by:

set in interface IConstantCollection

Parameters:

index - constant pool index [must be in [1, size()] range]

constant - new entry to set [may not be null; input unchecked]

Returns:

CONSTANT_info previous contents at this pool index [never null]

add

public int add(CONSTANT_info constant)

Description copied from interface: IConstantCollection

Appends 'constant' to the end of the collection. No duplicate checks are made.

Specified by:

add in interface IConstantCollection

Parameters:

constant - new constant [may not be null; input unchecked]

Returns:

the pool index of the newly added entry [always positive]

getCONSTANT_Utf8_index

private ObjectIntMap getCONSTANT_Utf8_index()