net.cscott.jutil
Class UniqueStack<E>

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList<E>
          net.cscott.jutil.UniqueVector<E>
              net.cscott.jutil.UniqueStack<E>

All Implemented Interfaces:

Cloneable, Iterable<E>, Collection<E>, List<E>, Set<E>

public class UniqueStack<E>
extends UniqueVector<E>

The UniqueStack class represents a last-in-first-out stack of unique objects.

Conforms to the JDK 1.2 Collections API.

Version:

$Id: UniqueStack.java,v 1.3 2006-10-30 19:58:07 cananian Exp $

Author:

C. Scott Ananian

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

UniqueStack()
Creates a UniqueStack.

UniqueStack(Collection<? extends E> c)
Constructs a UniqueStack containing the elements of the specified Collection, in the order they are returned by the collection's iterator in LIFO order.

Method Summary

boolean	empty() Tests if this stack is empty.
E	peek() Looks at the object at the top of this stack without removing it from the stack.
E	pop() Removes the object at the top of this stack and returns that object as the value of this function.
void	push(E item) Pushes an item onto the top of this stack, if it is unique.
int	search(Object o) Returns where an object is on this stack.

Methods inherited from class net.cscott.jutil.UniqueVector

add, add, addElement, capacity, clear, clone, contains, copyInto, elementAt, elements, ensureCapacity, equals, firstElement, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, lastElement, lastIndexOf, lastIndexOf, remove, removeAllElements, removeElement, removeElementAt, set, setElementAt, size, toArray, toArray, toString, trimToSize

Methods inherited from class java.util.AbstractList

addAll, iterator, listIterator, listIterator, removeRange, subList

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, remove, removeAll, retainAll

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

addAll, containsAll, iterator, remove, removeAll, retainAll

Methods inherited from interface java.util.List

addAll, containsAll, remove, removeAll, retainAll

Constructor Detail

UniqueStack

public UniqueStack()

Creates a UniqueStack.

UniqueStack

public UniqueStack(Collection<? extends E> c)

Constructs a UniqueStack containing the elements of the specified Collection, in the order they are returned by the collection's iterator in LIFO order. That is, the first item returned by the collection iterator will be at the bottom of the stack, and thus last to be popped. Duplicate elements in c are skipped.

Method Detail

push

public void push(E item)

Pushes an item onto the top of this stack, if it is unique. Otherwise, does nothing.

Parameters:

item - the item to be pushed onto this stack.

pop

public E pop()

Removes the object at the top of this stack and returns that object as the value of this function.

Returns:

The object at the top of this stack.

Throws:

EmptyStackException - if this empty.

peek

public E peek()

Looks at the object at the top of this stack without removing it from the stack.

Returns:

the object at the top of this stack.

Throws:

EmptyStackException - if this stack is empty.

empty

public boolean empty()

Tests if this stack is empty.

Returns:

true if this stack is empty; false otherwise.

search

public int search(Object o)

Returns where an object is on this stack.

Parameters:

o - the desired object.

Returns:

the distance from the top of the stack where the object is located; the return value -1 indicates that the object is not on the stack.