rp.util
Class TwoList

java.lang.Object
  |
  +--rp.util.TwoList

Direct Known Subclasses:

DOMObject, DOMRelation, DOMRelation.Endpoint

public class TwoList

extends java.lang.Object

A utility baseclass providing storage and associated functions operating on two doubly-linked circular lists, A and B. One element of the list is specially designated as the head.

Version:

$Revision: 1.1 $, $Date: 2001/06/25 15:03:48 $

Nested Class Summary

protected static interface	TwoList.Iterator Used for iterating over TwoList lists (A or B).
protected static class	TwoList.IteratorA An implementation of the Iterator interface for A-lists.
protected static class	TwoList.IteratorB An implementation of the Iterator interface for B-lists.

Field Summary

protected TwoList	headA
protected TwoList	headB
protected TwoList	nextA
protected TwoList	nextB
protected int	numsA
protected int	numsB
protected TwoList	prevA
protected TwoList	prevB

Constructor Summary

protected

TwoList() Initializes node storage as unused.

Method Summary

protected void	addA(TwoList head) Adds this element at the rear of the A-list headed by the parameter.
protected void	addB(TwoList head) Adds this element at the rear of the B-list headed by the parameter.
protected int	countA() Returns the number of nodes in the A-list of which this node is a part (or head).
protected int	countB() Returns the number of nodes in the B-list of which this node is a part (or head).
protected void	decommissionAsHeadA() Frees this A head node to be used again.
protected void	decommissionAsHeadB() Frees this B head node to be used again.
protected TwoList	firstA() Returns the first element on the A-list, or null if none.
protected TwoList	firstB() Returns the first element on the B-list, or null if none.
TwoList	headA() Returns the head of the A-list or null if not initialized.
TwoList	headB() Returns the head of the B-list or null if not initialized.
protected void	initAsHeadA() Initializes this node as the head of an empty A-list.
protected void	initAsHeadB() Initializes this node as the head of an empty B-list.
protected boolean	isElementA() Tests if this node is an element of an A-list (but not the head)
protected boolean	isElementB() Tests if this node is an element of a B-list (but not the head)
protected boolean	isHeadA() Tests if this node is a head of an A-list.
protected boolean	isHeadB() Tests if this node is a head of a B-list.
protected void	rmA() Removes this element from the A-list.
protected void	rmB()

Methods inherited from class java.lang.Object

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

Field Detail

numsA

protected int numsA

numsB

protected int numsB

headA

protected TwoList headA

headB

protected TwoList headB

nextA

protected TwoList nextA

nextB

protected TwoList nextB

prevA

protected TwoList prevA

prevB

protected TwoList prevB

Constructor Detail

TwoList

protected TwoList()

Initializes node storage as unused. Protected constructor indicating use as baseclass.

Method Detail

initAsHeadA

protected void initAsHeadA()

Initializes this node as the head of an empty A-list.

initAsHeadB

protected void initAsHeadB()

Initializes this node as the head of an empty B-list.

decommissionAsHeadA

protected void decommissionAsHeadA()

Frees this A head node to be used again.

decommissionAsHeadB

protected void decommissionAsHeadB()

Frees this B head node to be used again.

isHeadA

protected boolean isHeadA()

Tests if this node is a head of an A-list.

Returns:

if this node is the head of an A-list.

isHeadB

protected boolean isHeadB()

Tests if this node is a head of a B-list.

Returns:

if this node is the head of a B-list.

isElementA

protected boolean isElementA()

Tests if this node is an element of an A-list (but not the head)

Returns:

if this node is an element of an A-list.

isElementB

protected boolean isElementB()

Tests if this node is an element of a B-list (but not the head)

Returns:

if this node is an element of a B-list.

countA

protected int countA()

Returns the number of nodes in the A-list of which this node is a part (or head).

Returns:

the number of elements in the A-list.

countB

protected int countB()

Returns the number of nodes in the B-list of which this node is a part (or head).

Returns:

the number of elements in the B-list.

headA

public TwoList headA()

Returns the head of the A-list or null if not initialized.

Returns:

the head of the A-list.

headB

public TwoList headB()

Returns the head of the B-list or null if not initialized.

Returns:

the head of the B-list.

firstA

protected TwoList firstA()

Returns the first element on the A-list, or null if none. Only valid for heads.

Returns:

the first element on the A-list, or null if none.

firstB

protected TwoList firstB()

Returns the first element on the B-list, or null if none. Only valid for heads.

Returns:

the first element on the B-list, or null if none.

addA

protected void addA(TwoList head)

Adds this element at the rear of the A-list headed by the parameter.

Parameters:

head - the head of the list to which to add this element

addB

protected void addB(TwoList head)

Adds this element at the rear of the B-list headed by the parameter.

Parameters:

head - the head of the list to which to add this element

rmA

protected void rmA()

Removes this element from the A-list. Illegal for heads.

rmB

protected void rmB()