org.semanticweb.elk.util.concurrent.collections

Class SynchronizedArrayListActivationStack<E>

java.lang.Object

org.semanticweb.elk.util.concurrent.collections.SynchronizedArrayListActivationStack<E>

Type Parameters:

E - the type of elements in the stack

All Implemented Interfaces:

ActivationStack<E>

public class SynchronizedArrayListActivationStack<E>
extends Object
implements ActivationStack<E>

A simple implementation of ActivationStack using an ArrayList for storing elements; addition and removal of elements are synchronized.

Author:

"Yevgeny Kazakov"

Constructor Summary

Constructors

Constructor and Description
SynchronizedArrayListActivationStack()

Method Summary

Modifier and Type	Method and Description
E	peek() Returns but does not remove the head element of the stack.
E	pop() Takes and removes the head element of the stack.
boolean	push(E element) Inserts the given element at the head of the stack.

Methods inherited from class java.lang.Object

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

Constructor Detail

SynchronizedArrayListActivationStack

public SynchronizedArrayListActivationStack()

Method Detail

push

public boolean push(E element)

Description copied from interface: ActivationStack

Inserts the given element at the head of the stack. Returns true if this is the first element inserted after the stack has been cleared. A stack is clear in the beginning and is cleared every time ActivationStack.pop() returns null. Note that the stack might be empty in the sense that ActivationStack.pop() would return null, but not cleared.

Specified by:

push in interface ActivationStack<E>

Parameters:

element - the element to be inserted at the head of the stack

Returns:

true if this is the first element inserted after the stack has been cleared.

pop

public E pop()

Description copied from interface: ActivationStack

Takes and removes the head element of the stack.

Specified by:

pop in interface ActivationStack<E>

Returns:

the head element in the stack or null if there are no elements in the stack

peek

public E peek()

Description copied from interface: ActivationStack

Returns but does not remove the head element of the stack. This method does not modify the stack and calling this method does not have any effect on the results of the other methods.

Specified by:

peek in interface ActivationStack<E>

Returns:

the head element in the stack or null if there are no elements in the stack