org.apache.tomcat.util.digester
Class ArrayStack<E>

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList<E>
          java.util.ArrayList<E>
              org.apache.tomcat.util.digester.ArrayStack<E>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, RandomAccess

public class ArrayStack<E>
extends ArrayList<E>

Imported copy of the ArrayStack class from Commons Collections, which was the only direct dependency from Digester.

WARNNG - This class is public solely to allow it to be used from subpackages of org.apache.commons.digester. It should not be considered part of the public API of Commons Digester. If you want to use such a class yourself, you should use the one from Commons Collections directly.

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.

Unlike Stack, ArrayStack accepts null entries.

Since:

Digester 1.6 (from Commons Collections 1.0)

See Also:

Stack, Serialized Form

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

ArrayStack()
Constructs a new empty ArrayStack.

ArrayStack(int initialSize)
Constructs a new empty ArrayStack with an initial size.

Method Summary

boolean	empty() Return true if this stack is currently empty.
E	peek() Returns the top item off of this stack without removing it.
E	peek(int n) Returns the n'th item down (zero-relative) from the top of this stack without removing it.
E	pop() Pops the top item off of this stack and return it.
E	push(E item) Pushes a new item onto the top of this stack.

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, clone, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, remove, 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, 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, removeAll, retainAll, subList

Constructor Detail

ArrayStack

public ArrayStack()

Constructs a new empty ArrayStack. The initial size is controlled by ArrayList and is currently 10.

ArrayStack

public ArrayStack(int initialSize)

Constructs a new empty ArrayStack with an initial size.

Parameters:

initialSize - the initial size to use

Throws:

IllegalArgumentException - if the specified initial size is negative

Method Detail

empty

public boolean empty()

Return true if this stack is currently empty.

This method exists for compatibility with java.util.Stack. New users of this class should use isEmpty instead.

Returns:

true if the stack is currently empty

peek

public E peek()
       throws EmptyStackException

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

Returns:

the top item on the stack

Throws:

EmptyStackException - if the stack is empty

peek

public E peek(int n)
       throws EmptyStackException

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

Parameters:

n - the number of items down to go

Returns:

the n'th item on the stack, zero relative

Throws:

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

pop

public E pop()
      throws EmptyStackException

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

Returns:

the top item on the stack

Throws:

EmptyStackException - if the stack is empty

push

public E push(E item)

Pushes a new item onto the top of this stack. The pushed item is also returned. This is equivalent to calling add.

Parameters:

item - the item to be added

Returns:

the item just pushed