src/main/java/com/intel/jndn/utils/ClientObserver.java

/*
 * File name: ClientObserver.java
 * 
 * Purpose: 
 * 
 * © Copyright Intel Corporation. All rights reserved.
 * Intel Corporation, 2200 Mission College Boulevard,
 * Santa Clara, CA 95052-8119, USA
 */
package com.intel.jndn.utils;

import java.util.ArrayList;
import java.util.List;
import java.util.Observable;
import java.util.Observer;
import net.named_data.jndn.Data;
import net.named_data.jndn.Interest;
import net.named_data.jndn.OnData;

/**
 *
 * @author Andrew Brown <andrew.brown@intel.com>
 */
public class ClientObserver implements Observer {

  protected List<ClientObservableEvent> events = new ArrayList<>();
  protected long timestamp;
  protected OnData then;
  protected boolean stopThread;

  /**
   * Constructor
   */
  public ClientObserver() {
    timestamp = System.currentTimeMillis();
  }

  /**
   * Receive notifications from observables
   *
   * @param o
   * @param arg
   */
  @Override
  public void update(Observable o, Object arg) {
    ClientObservableEvent event = (ClientObservableEvent) arg;
    events.add(event);
    // call onData callbacks
    if (Data.class.isInstance(event.packet) && then != null) {
      then.onData(null, (Data) event.packet);
    }
  }

  /**
   * Register a handler for data packets
   *
   * @param handler
   * @return
   */
  public ClientObserver then(OnData handler) {
    then = handler;
    return this;
  }

  /**
   * Count the number of observed packets by type
   *
   * @param type
   * @return
   */
  public int count(Class type) {
    int count = 0;
    for (ClientObservableEvent event : events) {
      if (type.isInstance(event.packet)) {
        count++;
      }
    }
    return count;
  }

  /**
   * Count the number of interest packets observed (received or sent)
   *
   * @return
   */
  public int requests() {
    return count(Interest.class);
  }

  /**
   * Count the number of Data packets observed
   *
   * @return
   */
  public int responses() {
    return count(Data.class);
  }

  /**
   * Count the number of errors
   *
   * @return
   */
  public int errors() {
    return count(Exception.class);
  }

  /**
   * Get time since observer start
   *
   * @return
   */
  public long getTimeSinceStart() {
    if (getLast() != null) {
      return getLast().getTimestamp() - timestamp;
    }
    return -1;
  }

  /**
   * Retrieve first event
   *
   * @return event or null
   */
  public ClientObservableEvent getFirst() {
    if (events.size() > 0) {
      return events.get(0);
    }
    return null;
  }

  /**
   * Retrieve last event
   *
   * @return event or null
   */
  public ClientObservableEvent getLast() {
    if (events.size() > 0) {
      return events.get(events.size() - 1);
    }
    return null;
  }

  /**
   * Stop the current Client thread
   */
  public void stop() {
    stopThread = true;
  }

  /**
   * Check the current stop status
   *
   * @return
   */
  public boolean mustStop() {
    return stopThread;
  }
}