Android Open Source - ubihelper Subscription

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Back to project page ubihelper.

License

The source code is released under:

GNU General Public License

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Java Source Code

/**
 * Copyright (c) 2012 The University of Nottingham
 * //from  w  ww. j  a  va  2s.c  o  m
 * This file is part of ubihelper
 *
 *  ubihelper is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ubihelper is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with ubihelper. If not, see <http://www.gnu.org/licenses/>.
 *  
 *  @author Chris Greenhalgh (cmg@cs.nott.ac.uk), The University of Nottingham
 */

package uk.ac.horizon.ubihelper.channel;

import java.util.logging.Logger;

import org.json.JSONObject;

/** Subscription to a channel.
 * 
 * @author cmg
 *
 */
public abstract class Subscription {
  static Logger logger = Logger.getLogger(Subscription.class.getName());
  private String channelName;
  private String id;
  private double period;
  private long minInterval;
  private long expires = 0;
  private long lastValueTime = 0;
  /**
   * @param channel
   * @param id
   * @param period
   * @param minInterval
   */
  public Subscription(String channelName) {
    super();
    this.channelName = channelName;
  }

  public Subscription(String channelName, String subscriptionId) {
    super();
    this.channelName = channelName;
    this.id = subscriptionId;
  }

  /** update metadata */
  public synchronized void updateConfiguration(double period, double minInterval, double timeout) {
    this.period = period;
    this.minInterval = (long)(1000*minInterval);
    if (timeout==0) 
      expires = Long.MAX_VALUE;
    else
      expires = System.currentTimeMillis()+(long)(1000*timeout);
  }

  /** expired? */
  synchronized boolean isExpired() {
    return System.currentTimeMillis()>expires;
  }

  /** new value */
  synchronized void addValue(JSONObject value) {
    long now = System.currentTimeMillis();
    long elapsed = now-lastValueTime;
    if (elapsed<minInterval) {
      logger.warning("Discarded value, elapsed="+elapsed+" vs "+minInterval+"ms");
      return;
    }
    lastValueTime = now;
    handleAddValue(value);
  }
  
  protected abstract void handleAddValue(JSONObject value);

  /**
   * @return the channel
   */
  public String getChannelName() {
    return channelName;
  }
  /**
   * @return the id
   */
  public String getId() {
    return id;
  }
  /** from ChannelManager.addSubscription */
  void init(String id) {
    this.id = id;
  }
  /**
   * @return the period
   */
  public double getPeriod() {
    return period;
  }

  /**
   * @return the expires
   */
  public long getExpires() {
    return expires;
  }
  
}

Java Source Code List