net.datastructures
Interface Stack

All Known Implementing Classes:

ArrayStack, NodeStack

public interface Stack

Interface for a stack: a collection of objects that are inserted and removed according to the last-in first-out principle.

Author:

Roberto Tamassia, Michael Goodrich

See Also:

EmptyStackException

Method Summary

boolean	isEmpty() Return whether the stack is empty.
Object	pop() Remove the top element from the stack.
void	push(Object element) Insert an element at the top of the stack.
int	size() Return the number of elements in the stack.
Object	top() Inspect the element at the top of the stack.

Method Detail

size

public int size()

Return the number of elements in the stack.

Returns:

number of elements in the stack.

isEmpty

public boolean isEmpty()

Return whether the stack is empty.

Returns:

true if the stack is empty, false otherwise.

top

public Object top()
           throws EmptyStackException

Inspect the element at the top of the stack.

Returns:

top element in the stack.

Throws:

EmptyStackException - if the stack is empty.

push

public void push(Object element)

Insert an element at the top of the stack.

Parameters:

element - element to be inserted.

pop

public Object pop()
           throws EmptyStackException

Remove the top element from the stack.

Returns:

element removed.

Throws:

EmptyStackException - if the stack is empty.