Interface PureStack<E>

All Known Implementing Classes:

ArrayPureStack

public interface PureStack<E>

An interface for a PureStack, that is, a stack that only allows operations on the top of the stack. From Data Structures and the Java Collections Framework, 2nd ed, Collins

Method Summary

Modifier and Type	Method and Description
boolean	isEmpty() Determines if this PureStack object has no elements.
E	peek() Returns the top element on this PureStack object.
E	pop() Removes the top element from this PureStack object.
void	push(E element) Inserts a specified element on the top of this PureStack object.
int	size() Determines the number of elements in this PureStack object.

Method Detail

size

int size()

Determines the number of elements in this PureStack object.

Returns:

the number of elements in this PureStack object.

isEmpty

boolean isEmpty()

Determines if this PureStack object has no elements.

Returns:

true - if this PureStack object has no elements; otherwise, return false.

push

void push(E element)

Inserts a specified element on the top of this PureStack object. The averageTime(n) is constant and worstTime(n) is O(n).

Parameters:

element - - the element to be pushed.

pop

E pop()

Removes the top element from this PureStack object.

Returns:

- the element removed.

Throws:

NoSuchElementException - - if this PureStack object is empty.

peek

E peek()

Returns the top element on this PureStack object.

Returns:

- the element returned.

Throws:

NoSuchElementException - - if this PureStack object is empty.