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public class java.util.Stack

(source file: Stack.java)
java.lang.Object
   |
   +----java.util.AbstractCollection<A>
           |
           +----java.util.AbstractList<A>
                   |
                   +----java.util.Vector
                           |
                           +----java.util.Stack
The pure class interface. 
public class Stack
  extends Vector
The Stack class represents a last-in-first-out (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.

Constuctor Index

O Stack()

Methods

O empty()
Tests if this stack is empty.
O peek()
Looks at the object at the top of this stack without removing it from the stack
O pop()
Removes the object at the top of this stack and returns that object as the value of this
O push(Object)
Pushes an item onto the top of this stack
O search(Object)
Returns the 1-based position where an object is on this stack

Constructors

O Stack
public Stack();

Methods

O push
public Object push(Object item);
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:
addElement

O pop

public synchronized Object 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.

O peek

public synchronized Object 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.

O empty

public boolean empty();
Tests if this stack is empty.

Returns:
true if and only if this stack contains no items; false otherwise.

O search

public synchronized int search(Object o);
Returns the 1-based position where an object is on this stack. If the object o 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 distance 1. The equals method is used to compare o to the items in this stack.

Parameters:
o - the desired object.
Returns:
the 1-based 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.

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