org.vishia.util

Class QueuePrc<T>

java.lang.Object

org.vishia.util.QueuePrc<T>

Type Parameters:

T -

public abstract class QueuePrc<T>
extends java.lang.Object

Helper class to handle with queues. Basically, it prevents add to queue on already existing object in the queue.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) boolean	bPreventRequeue
(package private) java.util.Map<java.lang.String,T>	idxinQueue
(package private) java.util.List<T>	queue

Constructor Summary

Constructors

Constructor and Description
QueuePrc(boolean preventRequeue) Constructs

Method Summary

Modifier and Type	Method and Description
T	addToQueue(int pos, T obj) Adds an object to the queue and checks before whether it is contained already.
T	getFromQueue() Gets the next Object from begin of the queue and removes it also from the existence check.
abstract java.lang.String	key(T obj) Should be defined by usage.
void	reset(boolean preventRequeue) Resets the queue, cleans, also for prevent requeue.

Methods inherited from class java.lang.Object

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

Field Detail

queue

java.util.List<T> queue

idxinQueue

java.util.Map<java.lang.String,T> idxinQueue

bPreventRequeue

boolean bPreventRequeue

Constructor Detail

QueuePrc

public QueuePrc(boolean preventRequeue)

Constructs

Parameters:

preventRequeue - true means, later the same obj cannot be added again in the queue. If addToQueue(int, Object) is called with the same Object is prevented, till #reset() is called.

Method Detail

key

public abstract java.lang.String key(T obj)

Should be defined by usage. This operation should build a key which determines the functional same instance which may be already in queue to prevent multiple add to queue.

Parameters:

obj -

Returns:

String as key.

addToQueue

public T addToQueue(int pos,
                    T obj)

Adds an object to the queue and checks before whether it is contained already. The key to check contained is built with key(Object). This should be unique to identify the same instance.

Parameters:

pos - 0 on begin, -1 on end

obj - to add

Returns:

null if ok, else the already added instance with same key.

getFromQueue

public T getFromQueue()

Gets the next Object from begin of the queue and removes it also from the existence check. It means, later the same obj can be already added again in the queue.

Returns:

null if the queue is empty.

reset

public void reset(boolean preventRequeue)

Resets the queue, cleans, also for prevent requeue. The queue is empty as after ctor.

Parameters:

preventRequeue -