org.apache.struts.util
Class ArrayStack

java.lang.Object
  |
  +--org.apache.struts.util.ArrayStack

All Implemented Interfaces:

java.io.Serializable

public class ArrayStack

extends java.lang.Object

implements java.io.Serializable

Implementation of the java.util.Stack API that is based on an ArrayList rather than a Vector. This means no synchronization locks are utilized internally, so you must synchronize externally if an instance is referenced from multiple threads.

Version:

$Revision: 1.1 $ $Date: 2001/09/17 20:13:30 $

Author:

Craig R. McClanahan

See Also:

Serialized Form

Field Summary

protected java.util.ArrayList

list The underlying collection class.

Constructor Summary

ArrayStack()

Method Summary

void	clear() Remove all elements from this stack.
boolean	empty() Return true if this stack is currently empty.
java.lang.Object	peek() Return the top item off of this stack without removing it.
java.lang.Object	peek(int n) Return the n'th item down (zero-relative) from the top of this stack without removing it.
java.lang.Object	pop() Pop the top item off of this stack and return it.
java.lang.Object	push(java.lang.Object item) Push a new item onto the top of this stack.
int	size() Return the number of items on this stack.

Methods inherited from class java.lang.Object

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

Field Detail

list

protected java.util.ArrayList list

The underlying collection class.

Constructor Detail

ArrayStack

public ArrayStack()

Method Detail

clear

public void clear()

Remove all elements from this stack. After this call, the stack will be empty.

empty

public boolean empty()

Return true if this stack is currently empty.

peek

public java.lang.Object peek()
                      throws java.util.EmptyStackException

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

Throws:

EmptyStackExceptino - if the stack is empty

peek

public java.lang.Object peek(int n)
                      throws java.util.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:

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

pop

public java.lang.Object pop()
                     throws java.util.EmptyStackException

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

Throws:

java.util.EmptyStackException - if the stack is empty

push

public java.lang.Object push(java.lang.Object item)

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

Parameters:

item - Item to be added

size

public int size()

Return the number of items on this stack.