OpenJDK 1.22 · java.util.Stack · APIdia, the JavaDoc alternative

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>();

Modifier and Type	Field and Description
private static final long	serialVersionUID Hides java.util.Vector.serialVersionUID. use serialVersionUID from JDK 1.0.2 for interoperability

Constructor Summary

Access	Constructor and Description
public	Stack() Creates an empty Stack.

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: `true` if and only if this stack contains no items; `false` otherwise. empty() Tests if this stack is empty.
public synchronized E	Returns: the object at the top of this stack (the last item of the `Vector` object). peek() Looks at the object at the top of this stack without removing it from the stack.
public synchronized E	Returns: The object at the top of this stack (the last item of the `Vector` object). pop() Removes the object at the top of this stack and returns that object as the value of this function.
public E	Returns: the `item` argument. push(E the item to be pushed onto this stack. item) Pushes an item onto the top of this stack.
public synchronized int	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. search(Object the desired object. o) Returns the 1-based position where an object is on this stack.

Field Detail

serialVersionUID	back to summary
private static final long serialVersionUID Hides java.util.Vector.serialVersionUID. use serialVersionUID from JDK 1.0.2 for interoperability Annotations @Serial

serialVersionUID

back to summary

private static final long serialVersionUID

Hides java.util.Vector.serialVersionUID.

use serialVersionUID from JDK 1.0.2 for interoperability

Annotations

@Serial

Constructor Detail

Stack	back to summary
public Stack() Creates an empty Stack.

Method Detail

empty back to summary

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

public boolean empty()

Tests if this stack is empty.

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

peek back to summary

peek	back to summary
public synchronized E peek() Looks at the object at the top of this stack without removing it from the stack. Returns:E the object at the top of this stack (the last item of the `Vector` object). Exceptions EmptyStackException: if this stack is empty.

public synchronized E peek()

Looks at the object at the top of this stack without removing it from the stack.

Returns:E

the object at the top of this stack (the last item of the Vector object).

Exceptions

EmptyStackException:: if this stack is empty.

pop back to summary

pop	back to summary
public synchronized E pop() Removes the object at the top of this stack and returns that object as the value of this function. Returns:E The object at the top of this stack (the last item of the `Vector` object). Exceptions 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:E

The object at the top of this stack (the last item of the Vector object).

Exceptions

EmptyStackException:: if this stack is empty.

push back to summary

push	back to summary
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:E the item to be pushed onto this stack. Returns:E the `item` argument. See Also `java.util.Vector#addElement`

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:E: the item to be pushed onto this stack.

Returns:E

the item argument.

See Also

java.util.Vector#addElement

search back to summary

search	back to summary
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:Object the desired object. Returns:int 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.

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:Object: the desired object.

Returns:int

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.

public Class Stack<E>

Field Summary

Constructor Summary

Method Summary

Field Detail

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Method Detail