de.rwth.utils
Class Position

java.lang.Object
  |
  +--de.rwth.utils.Position

public class Position

extends java.lang.Object

Describes positions in a tree as sequence of child selection indices from the root.

Version:

$Id: Position.java,v 1.2 2002/09/17 06:53:53 mohnen Exp $

Author:

Markus Mohnen

Inner Class Summary

class

Position.Entry Describes a single child selection index;

Field Summary

protected java.util.Stack

stack The representation of the position.

Constructor Summary

Position()
Creates a new Position instance.

Method Summary

boolean	empty() Checks if the Position has no entries.
Position.Entry	get(int i) Returns the element at the specified index (0 for beginning).
boolean	isBelow(Position p) Checks if this position is below another position p.
java.util.Iterator	iterator() Returns an iterator over the entries in this position in proper sequence.
Position.Entry	peek() Looks at the object at the top of this position without removing it.
Position.Entry	pop() Removes the entry at the top of this posotion and returns that entry.
void	push(java.lang.Object o, int i) Creates a new Entry and pushes it onto the top of this position.
void	push(Position.Entry e) Pushes an entry onto the top of this position.
int	size() Returns the number of components.
java.lang.String	toShortString() Creates a short string representation by omitting the objects in the entries.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

stack

protected java.util.Stack stack

The representation of the position.

Constructor Detail

Position

public Position()

Creates a new Position instance.

Method Detail

empty

public boolean empty()

Checks if the Position has no entries.

Returns:

a boolean value

peek

public Position.Entry peek()

Looks at the object at the top of this position without removing it.

Returns:

an Entry value

size

public int size()

Returns the number of components.

Returns:

an int value

push

public void push(Position.Entry e)

Pushes an entry onto the top of this position.

Parameters:

e - an Entry value

push

public void push(java.lang.Object o,
                 int i)

Creates a new Entry and pushes it onto the top of this position.

Parameters:

o - an Object value

i - an int value

pop

public Position.Entry pop()

Removes the entry at the top of this posotion and returns that entry.

Returns:

an Entry value

get

public Position.Entry get(int i)

Returns the element at the specified index (0 for beginning). If the position is less than zero, the positive index counts from the end of the position.

Parameters:

i - an int value: postion

Returns:

an Entry value

iterator

public java.util.Iterator iterator()

Returns an iterator over the entries in this position in proper sequence.

Returns:

an Iterator value

isBelow

public boolean isBelow(Position p)

Checks if this position is below another position p. This is the case iff p is a prefix of this position.

Parameters:

p - a Position value

Returns:

a boolean value

toShortString

public java.lang.String toShortString()

Creates a short string representation by omitting the objects in the entries.

Returns:

a String value

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object