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/OpenJDK 8

Class 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 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>();
Since:
JDK1.0

Fields

Fields inherited from class java.util.Vector

capacityIncrement, elementCount, elementData

Fields inherited from class java.util.AbstractList

modCount

Constructors

Stack

public Stack()

Creates an empty Stack.

Methods

push

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:
Vector.addElement(E)

pop

public 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

public 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.

empty

public boolean empty()

Tests if this stack is empty.

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

search

public 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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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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