org.apache.tomcat.util.digester
Class ArrayStack

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

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable, java.util.Collection, java.util.List, java.util.RandomAccess

public class ArrayStack
extends java.util.ArrayList

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

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:

java.lang.IllegalArgumentException - if the specified initial size is negative

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

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

Returns:

the top item on the stack

Throws:

java.util.EmptyStackException - if the stack is empty

peek

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

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

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

Returns:

the top item on the stack

Throws:

java.util.EmptyStackException - if the stack is empty

push

public java.lang.Object push(java.lang.Object 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

search

public int search(java.lang.Object object)

Returns 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:

object - the object to be searched for

Returns:

the 1-based depth into the stack of the object, or -1 if not found