/* ====================================================================
* Limited Evaluation License:
*
* This software is open source, but licensed. The license with this package
* is an evaluation license, which may not be used for productive systems. If
* you want a full license, please contact us.
*
* The exclusive owner of this work is the OpenRate project.
* This work, including all associated documents and components
* is Copyright of the OpenRate project 2006-2015.
*
* The following restrictions apply unless they are expressly relaxed in a
* contractual agreement between the license holder or one of its officially
* assigned agents and you or your organisation:
*
* 1) This work may not be disclosed, either in full or in part, in any form
* electronic or physical, to any third party. This includes both in the
* form of source code and compiled modules.
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* methods and technologies. These trade secrets may not be disclosed to
* third parties in any form, either directly or in summary or paraphrased
* form, nor may these trade secrets be used to construct products of a
* similar or competing nature either by you or third parties.
* 3) This work may not be included in full or in part in any application.
* 4) You may not remove or alter any proprietary legends or notices contained
* in or on this work.
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* you received this work in a compiled form.
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* 9) You agree to use this software exclusively for evaluation purposes, and
* that you shall not use this software to derive commercial profit or
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* (including but not limited to, procurement of substitute goods or services;
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* This software contains portions by The Apache Software Foundation, Robert
* Half International.
* ====================================================================
*/
package OpenRate.buffer;
import OpenRate.record.IRecord;
import java.util.Collection;
import java.util.LinkedList;
/**
* Buffer implementation using an LinkedListQueue as the buffering element.
* As this is one of the performance sensitive parts of the system, you might
* want to define different buffering structures, depending on the limitations
* of the application that you are working on. However the ArrayListQueue will
* fulfill the requirements for a large majority of applications, as it:
* - Preserves record ordering
* - Allows easy addition and extraction
* - Is reasonably fast
*/
public class LinkedListQueueBuffer
extends AbstractBuffer
{
// The main storage object of the buffer
private LinkedList<IRecord> queueHelperBatch;
// the locking object so that we make sure that the multi-threadedness of
// the object is guaranteed
private final Object lock;
/**
* Default constructor.
*/
public LinkedListQueueBuffer()
{
super();
//queueHelper = Collections.synchronizedList(new LinkedList());
queueHelperBatch = new LinkedList<>();
lock = new Object();
}
/**
* Push an entire collection of batch records into the buffer.
* This is the main event for the addition of records into a buffer.
*
* @param collection The collection of records to push
*/
@Override
public void push(Collection<IRecord> collection)
{
synchronized (lock)
{
// blocks waiting for queue availability.
queueHelperBatch.addAll(collection);
}
// tell the downstream modules that there is stuff to do
notifyMonitors();
}
/**
* Retrieve a number of batch records from the buffer. The number of records
* that is returned is either all of the records available in the case that the
* number of records is less than the specified maximum, or the specified
* maximum. Note that the primary reason for limiting the number of records
* that can be pulled at a time is to:
* - make sure that a particularly slow module does not block the processing
* - to allow multiple instances of the same plug in to work on records
* in parallel, thus removing bottlenecks
*
* Note that the records are retrieved from the head of the list, despite the
* fact that retrieving from the tail could provide a higher performance. In
* the case that you really do not care about ordering, you could tweak this.
*/
@Override
public Collection<IRecord> pull(int max)
{
LinkedList<IRecord> list = new LinkedList<>();
synchronized (lock)
{
int size = queueHelperBatch.size();
for (int i = 0; (i < max) && (size > 0); ++i)
{
// It would be faster to pull from the end of the array instead
// of the beginning, but if order matters (and mostly it will) we have
// to work from the head of the queue.
// In cases where order really does not matter, we could use:
// Object o = queueHelper.remove(--size);
IRecord o = queueHelperBatch.remove();
list.add(o);
}
}
return list;
}
/**
* Return the number of events in the buffer
*/
@Override
public int getEventCount()
{
return queueHelperBatch.size();
}
}