Stack - JRE Emulation | JRE Emulation
public class

Stack

extends Vector<E>
java.lang.Object
   ↳ java.util.AbstractCollection<E>
     ↳ java.util.AbstractList<E>
       ↳ java.util.Vector<E>
         ↳ java.util.Stack<E>

Class Overview

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.

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>();

Summary

[Expand]
Inherited Fields
From class java.util.Vector
From class java.util.AbstractList
Public Constructors
Stack()
Creates an empty Stack.
Public Methods
boolean empty()
Tests if this stack is empty.
synchronized E peek()
Looks at the object at the top of this stack without removing it from the stack.
synchronized 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.
synchronized int search(Object o)
Returns the 1-based position where an object is on this stack.
Inherited Methods
[Expand]
From class java.util.Vector
From class java.util.AbstractList
From class java.util.AbstractCollection
From class java.lang.Object
From interface java.util.List
From interface java.util.Collection
From interface java.lang.Iterable

Public Constructors

public Stack ()

Creates an empty Stack.

Public Methods

public boolean empty ()

Tests if this stack is empty.

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

public synchronized E 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.

public synchronized 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.

public E push (E 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

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.