org.eclipse.hyades.collection.correlation
Class Stack

java.lang.Object
  org.eclipse.hyades.collection.correlation.Stack

Direct Known Subclasses:

CorrelatorStack, ServiceRegistry

public class Stack

extends java.lang.Object

This class offers a simple and efficient implementation of a thread-safe, growable stack.

Field Summary

protected int	increment The size by which the stack grows if more space is required.
java.lang.Object	privateStorage Any private storage that may be necessary for this class.
protected java.lang.Object[]	stack The stack of objects.
protected int	top The top-most item on the stack.

Constructor Summary

Stack(int size, int increment)
Creates an empty stack of size with an increment for holding Objects.

Method Summary

java.lang.Object	peek() Peeks at the top-most item on the stack, or returns null if the stack is empty.
java.lang.Object	peek(int offset) Peeks at the offsetth item from the top of the stack, with the top-most item being 0.
java.lang.Object	pop() Pops the top-most item off the stack, or null if the stack if empty.
void	push(java.lang.Object item) Pushes an item onto the stack.

Methods inherited from class java.lang.Object

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

Field Detail

stack

protected java.lang.Object[] stack

The stack of objects.

top

protected int top

The top-most item on the stack. A value of -1 indicates that the stack is currently empty.

increment

protected int increment

The size by which the stack grows if more space is required.

privateStorage

public java.lang.Object privateStorage

Any private storage that may be necessary for this class. This is particularly useful when the generality of a super-class and the specialization of a sub-class are desired at the same time, making sub-classing unfeasible. This field is not managed by the class.

Constructor Detail

Stack

public Stack(int size,
             int increment)

Creates an empty stack of size with an increment for holding Objects.

Parameters:

size - the initial size of the stack

increment - the size by which the stack grows if its current capacity is insufficient

Method Detail

peek

public java.lang.Object peek()

Peeks at the top-most item on the stack, or returns null if the stack is empty.

Returns:

the top-most item on the stack, or null if the stack is empty.

peek

public java.lang.Object peek(int offset)

Peeks at the offsetth item from the top of the stack, with the top-most item being 0.

Parameters:

offset - any non-negative value indicating the desired item on the stack

Returns:

the offsetth item from the top of the stack, or null if the offset is out of range.

push

public void push(java.lang.Object item)

Pushes an item onto the stack. If there is no room left on the stack, the size of the stack is incremented automatically by increment, after which the item is pushed onto the new stack.

Parameters:

item - the object to be pushed onto the stack

pop

public java.lang.Object pop()

Pops the top-most item off the stack, or null if the stack if empty.

Returns:

the top-most item on the stack, or null if the stack is empty.