org.apache.commons.collections
Class ArrayStack

java.lang.Object
  |
  +--java.util.AbstractCollection
        |
        +--java.util.AbstractList
              |
              +--java.util.ArrayList
                    |
                    +--org.apache.commons.collections.ArrayStack

All Implemented Interfaces:

Cloneable, Collection, List, Serializable

public class ArrayStack

extends ArrayList

An implementation of the Stack API that is based on an ArrayList instead of a Vector, so it is not synchronized to protect against multi-threaded access. The implementation is therefore operates faster in environments where you do not need to worry about multiple thread contention.

Version:

$Revision: 1.4 $ $Date: 2002/02/10 08:07:42 $

Author:

Craig R. McClanahan

See Also:

Stack, Serialized Form

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

ArrayStack()

Method Summary

boolean	empty() Return true if this stack is currently empty.
Object	peek() Return the top item off of this stack without removing it.
Object	peek(int n) Return the n'th item down (zero-relative) from the top of this stack without removing it.
Object	pop() Pop the top item off of this stack and return it.
Object	push(Object item) Push a new item onto the top of this stack.
int	search(Object o) Return the one-based position of the distance from the top that the specified object exists on this stack, where the top-most element is considered to be at distance 1.

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, clone, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, remove, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

equals, hashCode, iterator, listIterator, listIterator, subList

Methods inherited from class java.util.AbstractCollection

containsAll, remove, removeAll, retainAll, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.List

containsAll, equals, hashCode, iterator, listIterator, listIterator, remove, removeAll, retainAll, subList

Constructor Detail

ArrayStack

public ArrayStack()

Method Detail

empty

public boolean empty()

Return true if this stack is currently empty.

peek

public Object peek()
            throws EmptyStackException

Return the top item off of this stack without removing it.

Throws:

EmptyStackExceptino - if the stack is empty

peek

public Object peek(int n)
            throws EmptyStackException

Return the n'th item down (zero-relative) from the top of this stack without removing it.

Parameters:

n - Number of items down to go

Throws:

EmptyStackException - if there are not enough items on the stack to satisfy this request

pop

public Object pop()
           throws EmptyStackException

Pop the top item off of this stack and return it.

Throws:

EmptyStackException - if the stack is empty

push

public Object push(Object item)

Push a new item onto the top of this stack. The pushed item is also returned.

Parameters:

item - Item to be added

search

public int search(Object o)

Return the one-based position of the distance from the top that the specified object exists on this stack, where the top-most element is considered to be at distance 1. If the object is not present on the stack, return -1 instead. The equals() method is used to compare to the items in this stack.

Parameters:

o - Object to be searched for