jist.swans.misc
Class Mapper

java.lang.Object
  jist.swans.misc.Mapper

public final class Mapper
extends java.lang.Object

Encodes a one-to-one mapping. Used, for example, to dynamically assign port numbers consistently, but in a smaller index range, in order to reduce array sizes.

Since:

SWANS1.0

Version:

$Id: Mapper.java,v 1.8 2004/04/06 16:07:48 barr Exp $

Author:

Rimon Barr <barr+jist@cs.cornell.edu>

Field Summary

private int	limit Mapped (range) limit.
static int	MAP_INVALID Invalid mapping constant.
private int[]	mapFrom Reverse mapping table.
private int[]	mapTo Forward mapping table.
private boolean	sealed Whether this mapping is sealed.

Constructor Summary

Mapper(int max)
Create a mapping with a given index cap.

Mapper(int[] values)
Create a sealed mapping of the provided values.

Method Summary

int	getLimit() Return limit of the range of this mapping.
int	getMap(int i) Return element in the range of the mapping.
int	getMapR(int j) Return element in the domain of the mapping.
private void	init(int max) Private constructor helper method.
private int	map(int i, int j) Define a mapping.
int	mapToNext(int i) Define a mapping.
void	seal() Seal the current mapping; prevent further changes.
int	testMapToNext(int i) Define a mapping if one does not already exist.

Methods inherited from class java.lang.Object

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

Field Detail

MAP_INVALID

public static final int MAP_INVALID

Invalid mapping constant.

See Also:

Constant Field Values

mapTo

private int[] mapTo

Forward mapping table.

mapFrom

private int[] mapFrom

Reverse mapping table.

limit

private int limit

Mapped (range) limit.

sealed

private boolean sealed

Whether this mapping is sealed.

Constructor Detail

Mapper

public Mapper(int max)

Create a mapping with a given index cap.

Parameters:

max - map indices should be non-negative and less than max.

Mapper

public Mapper(int[] values)

Create a sealed mapping of the provided values.

Parameters:

values - array of domain values to map.

Method Detail

init

private void init(int max)

Private constructor helper method.

Parameters:

max - map indices should be non-negative and less than max.

seal

public void seal()

Seal the current mapping; prevent further changes.

map

private int map(int i,
                int j)

Define a mapping. Map i onto j.

Parameters:

i - integer in domain of mapping

j - integer in range of mapping

Returns:

j

mapToNext

public int mapToNext(int i)

Define a mapping. Map i onto one more than the highest value in the range of the mapping.

Parameters:

i - integer in the domain of mapping

Returns:

selected value in the range of the mapping

testMapToNext

public int testMapToNext(int i)

Define a mapping if one does not already exist. Map i onto one more than the highest value in the range of the mapping, unless it is already mapped.

Parameters:

i - integer in the domain of mapping

Returns:

new or corresponding integer in the range of the mapping

getMap

public int getMap(int i)

Return element in the range of the mapping.

Parameters:

i - integer in the domain of the mapping

Returns:

corresponding integer in the range of the mapping

getMapR

public int getMapR(int j)

Return element in the domain of the mapping.

Parameters:

j - integer in the range of the mapping

Returns:

corresponding integer in the domain of the mapping

getLimit

public int getLimit()

Return limit of the range of this mapping.

Returns:

range limit of mapping