cpsc331.collections

Class ArrayStack<E>

java.lang.Object

cpsc331.collections.ArrayStack<E>

All Implemented Interfaces:

BoundedStack<E>

public class ArrayStack<E>
extends java.lang.Object
implements BoundedStack<E>

Provides an implementation of a BoundedStack using an ArrayList whose capacity is never allowed to change.

The constructor requires time linear in the capacity of the BoundedStack being created. All other operations require constant time in the worst case.

Constructor Summary

Constructors

Constructor and Description
ArrayStack(int maxSize) Creates an ArrayList whose size and capacity are both equal to the input maxSize, and whose entries are all null, if this is a positive int - throwing an IllegalArgumentException if the input maxSize is negative, instead.

Method Summary

Modifier and Type	Method and Description
int	capacity() Reports the capacity of this bounded stack.
boolean	isEmpty() Reports whether the stack is currently empty without changing it.
E	peek() Reports the top element of the stack without changing it.
E	pop() Removes an element from the top of the stack and reports it.
void	push(E x) Pushes a new entry onto the stack.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ArrayStack

public ArrayStack(int maxSize)

Creates an ArrayList whose size and capacity are both equal to the input maxSize, and whose entries are all null, if this is a positive int - throwing an IllegalArgumentException if the input maxSize is negative, instead.

Parameters:

maxSize - the capacity of the BoundedStack to be created

Method Detail

push

public void push(E x)
          throws StackFullException

Description copied from interface: BoundedStack

Pushes a new entry onto the stack.

Specified by:

push in interface BoundedStack<E>

Parameters:

x - the object to be pushed onto the stack

Throws:

StackFullException - if the Stack is already full

Precondition:

1. The BoundedStack Invariant is satisfied.
2. An element x of type E has been given as input.

Postcondition:

1. The BoundedStack Invariant is satisfied.
2. If the number of objects presently on this bounded stack was less than the bounded stack's capacity, then the input object x has been pushed onto the top of the stack (which is otherwise unchanged).
3. If the number of objects presently on the bounded stack was equal to the bounded stack's capacity, then a StackFullException is thrown and the stack is not changed.

peek

public E peek()

Description copied from interface: BoundedStack

Reports the top element of the stack without changing it.

Specified by:

peek in interface BoundedStack<E>

Returns:

the element at the top of the stack

pop

public E pop()

Description copied from interface: BoundedStack

Removes an element from the top of the stack and reports it.

Specified by:

pop in interface BoundedStack<E>

Returns:

the element removed from the stack

isEmpty

public boolean isEmpty()

Description copied from interface: BoundedStack

Reports whether the stack is currently empty without changing it.

Specified by:

isEmpty in interface BoundedStack<E>

Returns:

true if the stack is empty, and false otherwise

Precondition:

1. The BoundedStack Invariant is satisfied.

Postcondition:

1. The BoundedStack Invariant is satisfied.
2. The bounded stack is not changed.
3. If the bounded stack was empty before this operation then “true” is returned as output.
4. If the bounded stack was not empty before this operation then “false” is returned as output.

capacity

public int capacity()

Description copied from interface: BoundedStack

Reports the capacity of this bounded stack.

Specified by:

capacity in interface BoundedStack<E>

Returns:

the capacity of this BoundedStack

Precondition:

1. The BoundedStack Invariant is satisfied.

Postcondition:

1. The BoundedStack Invariant is satisfied.
2. The bounded stack is not changed.
3. The capacity of this bounded stack is returned as output.