org.apache.commons.collections
Class ArrayStack
ArrayList
org.apache.commons.collections.ArrayStack
- Buffer, Collection
public class ArrayStack
extends ArrayList
An implementation of the
java.util.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.
The removal order of an
ArrayStack
is based on insertion
order: The most recently added element is removed first. The iteration
order is
not the same as the removal order. The iterator returns
elements from the bottom up, whereas the
remove()
method removes
them from the top down.
Unlike
Stack
,
ArrayStack
accepts null entries.
Note: this class should be bytecode-identical to the
version in commons collections. This is required to allow backwards
compability with both previous versions of BeanUtils and also allow
coexistance with both collections 2.1 and 3.0.
$Revision: 1.1 $ $Date: 2004/05/10 19:50:13 $- Craig R. McClanahan
- Paul Jack
- Stephen Colebourne
ArrayStack() - Constructs a new empty
ArrayStack .
|
ArrayStack(int initialSize) - Constructs a new empty
ArrayStack with an initial size.
|
boolean | empty() - Return
true if this stack is currently empty.
|
Object | get() - Returns the element on the top of the stack.
|
Object | peek() - Returns the top item off of this stack without removing it.
|
Object | peek(int n) - Returns the n'th item down (zero-relative) from the top of this
stack without removing it.
|
Object | pop() - Pops the top item off of this stack and return it.
|
Object | push(Object item) - Pushes a new item onto the top of this stack.
|
Object | remove() - Removes the element on the top of the stack.
|
int | search(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 .
|
serialVersionUID
private static final long serialVersionUID
Ensure serialization compatibility
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.
initialSize
- the initial size to use
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.
- true if the stack is currently empty
get
public Object get()
Returns the element on the top of the stack.
- get in interface Buffer
- the element on the top of the stack
peek
public Object peek()
throws EmptyStackException
Returns the top item off of this stack without removing it.
- the top item on the stack
peek
public Object peek(int n)
throws EmptyStackException
Returns the n'th item down (zero-relative) from the top of this
stack without removing it.
n
- the number of items down to go
- the n'th item on the stack, zero relative
pop
public Object pop()
throws EmptyStackException
Pops the top item off of this stack and return it.
- the top item on the stack
push
public Object push(Object item)
Pushes a new item onto the top of this stack. The pushed item is also
returned. This is equivalent to calling add
.
item
- the item to be added
remove
public Object remove()
Removes the element on the top of the stack.
- remove in interface Buffer
search
public int search(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.
object
- the object to be searched for
- the 1-based depth into the stack of the object, or -1 if not found
Copyright (c) 2001-2004 - Apache Software Foundation