java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractList<E>
java.util.Vector<E>
java.util.Stack<E>
 All Implemented Interfaces:
Serializable
,Cloneable
,Iterable<E>
,Collection<E>
,List<E>
,RandomAccess
public class Stack<E> extends Vector<E>
The
Stack
class represents a lastinfirstout
(LIFO) stack of objects. It extends class Vector
with five
operations that allow a vector to be treated as a stack. The usual
push
and pop
operations are provided, as well as a
method to peek
at the top item on the stack, a method to test
for whether the stack is empty
, and a method to search
the stack for an item and discover how far it is from the top.
When a stack is first created, it contains no items.
A more complete and consistent set of LIFO stack operations is
provided by the Deque
interface and its implementations, which
should be used in preference to this class. For example:
Deque<Integer> stack = new ArrayDeque<Integer>();
 Since:
 1.0
 See Also:
 Serialized Form

Field Summary

Constructor Summary
Constructors Constructor Description Stack()
Creates an empty Stack. 
Method Summary
Modifier and Type Method Description boolean
empty()
Tests if this stack is empty.E
peek()
Looks at the object at the top of this stack without removing it from the stack.E
pop()
Removes the object at the top of this stack and returns that object as the value of this function.E
push(E item)
Pushes an item onto the top of this stack.int
search(Object o)
Returns the 1based position where an object is on this stack.Methods declared in class java.util.Vector
add, add, addAll, addAll, addElement, capacity, clear, clone, contains, containsAll, copyInto, elementAt, elements, ensureCapacity, equals, firstElement, forEach, get, hashCode, indexOf, indexOf, insertElementAt, isEmpty, iterator, lastElement, lastIndexOf, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeAllElements, removeElement, removeElementAt, removeIf, removeRange, replaceAll, retainAll, set, setElementAt, setSize, size, spliterator, subList, toArray, toArray, toString, trimToSize

Constructor Details

Stack
public Stack()Creates an empty Stack.


Method Details

push
Pushes an item onto the top of this stack. This has exactly the same effect as:addElement(item)
 Parameters:
item
 the item to be pushed onto this stack. Returns:
 the
item
argument.  See Also:
Vector.addElement(E)

pop
Removes the object at the top of this stack and returns that object as the value of this function. Returns:
 The object at the top of this stack (the last item
of the
Vector
object).  Throws:
EmptyStackException
 if this stack is empty.

peek
Looks at the object at the top of this stack without removing it from the stack. Returns:
 the object at the top of this stack (the last item
of the
Vector
object).  Throws:
EmptyStackException
 if this stack is empty.

empty
public boolean empty()Tests if this stack is empty. Returns:
true
if and only if this stack contains no items;false
otherwise.

search
Returns the 1based position where an object is on this stack. If the objecto
occurs as an item in this stack, this method returns the distance from the top of the stack of the occurrence nearest the top of the stack; the topmost item on the stack is considered to be at distance1
. Theequals
method is used to compareo
to the items in this stack. Parameters:
o
 the desired object. Returns:
 the 1based position from the top of the stack where
the object is located; the return value
1
indicates that the object is not on the stack.
