org.apache.commons.collections
public class ArrayStack extends ArrayList implements Buffer
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.
Since: Commons Collections 1.0
Version: $Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
See Also: java.util.Stack
Constructor Summary | |
---|---|
ArrayStack()
Constructs a new empty ArrayStack . | |
ArrayStack(int initialSize)
Constructs a new empty ArrayStack with an initial size.
|
Method Summary | |
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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 . |
ArrayStack
. The initial size
is controlled by ArrayList
and is currently 10.ArrayStack
with an initial size.
Parameters: initialSize the initial size to use
Throws: IllegalArgumentException if the specified initial size is negative
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
Returns: the element on the top of the stack
Throws: BufferUnderflowException if the stack is empty
Returns: the top item on the stack
Throws: EmptyStackException if the stack is empty
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
Returns: the top item on the stack
Throws: EmptyStackException if the stack is empty
add
.
Parameters: item the item to be added
Returns: the item just pushed
Returns: the removed element
Throws: BufferUnderflowException if the stack is empty
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