/*   **********************************************************************  **
 **   Copyright notice                                                       **
 **                                                                          **
 **   (c) 2005-2006 RSSOwl Development Team                                  **
 **   http://www.rssowl.org/                                                 **
 **                                                                          **
 **   All rights reserved                                                    **
 **                                                                          **
 **   This program and the accompanying materials are made available under   **
 **   the terms of the Eclipse Public License v1.0 which accompanies this    **
 **   distribution, and is available at:                                     **
 **   http://www.rssowl.org/legal/epl-v10.html                               **
 **                                                                          **
 **   A copy is found in the file epl-v10.html and important notices to the  **
 **   license from the team is found in the textfile LICENSE.txt distributed **
 **   in this package.                                                       **
 **                                                                          **
 **   This copyright notice MUST APPEAR in all copies of the file!           **
 **                                                                          **
 **   Contributors:                                                          **
 **     RSSOwl Development Team - initial API and implementation             **
 **                                                                          **
 **  **********************************************************************  */

package org.rssowl.core.util;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * @author bpasero
 * @param <T>
 */
public abstract class BatchedBuffer<T> {
  private int fBatchInterval;
  private List<T> fBuffer;
  private Job fBufferProcessor;

  /**
   * @param batchInterval
   */
  protected BatchedBuffer(int batchInterval) {
    fBatchInterval = batchInterval;
    fBuffer = new ArrayList<T>();
    fBufferProcessor = createBufferProcessor();
  }

  private Job createBufferProcessor() {
    Job job = new Job("Batched Buffer Processor") {
      @Override
      protected IStatus run(IProgressMonitor monitor) {
        synchronized (fBuffer) {
          receive(new HashSet<T>(fBuffer));
          fBuffer.clear();
        }

        return Status.OK_STATUS;
      }
    };

    job.setSystem(true);
    job.setUser(false);

    return job;
  }

  /**
   * @param objects
   */
  public abstract void receive(Set<T> objects);

  /**
   * @param objects
   */
  public void add(Set<T> objects) {
    synchronized (fBuffer) {

      /* New Batch */
      if (fBuffer.isEmpty()) {
        fBuffer.addAll(objects);
        fBufferProcessor.schedule(fBatchInterval);
      }

      /* Existing Batch */
      else {
        fBuffer.addAll(objects);
      }
    }
  }
}