InstagramDataCollector.java

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regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance *
http://www.apache.org/licenses/LICENSE-2.0 *
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package org.apache.streams.instagram.provider;

import org.apache.streams.core.StreamsDatum;
import org.apache.streams.instagram.api.Instagram;
import org.apache.streams.instagram.config.InstagramConfiguration;
import org.apache.streams.instagram.config.InstagramOAuthConfiguration;
import org.apache.streams.util.ComponentUtils;
import org.apache.streams.util.api.requests.backoff.BackOffStrategy;
import org.apache.streams.util.api.requests.backoff.impl.ExponentialBackOffStrategy;
import org.apache.streams.util.oauth.tokens.tokenmanager.SimpleTokenManager;
import org.apache.streams.util.oauth.tokens.tokenmanager.impl.BasicTokenManager;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collection;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Executes on all of the Instagram requests to collect the Instagram data.
 * <p/>
 * If errors/exceptions occur when trying to gather data for a particular user, that user is skipped and the collector
 * move on to the next user.  If a rate limit exception occurs it employs an exponential back off strategy.
 */
public abstract class InstagramDataCollector<T> implements Runnable {

  private static final Logger LOGGER = LoggerFactory.getLogger(InstagramDataCollector.class);

  protected Queue<StreamsDatum> dataQueue; //exposed for testing
  private InstagramConfiguration config;
  protected AtomicBoolean isCompleted;
  private SimpleTokenManager<InstagramOAuthConfiguration> tokenManger;
  protected int consecutiveErrorCount;
  protected BackOffStrategy backOffStrategy;
  private Instagram instagram;

  /**
   * InstagramDataCollector constructor.
   * @param queue Queue of StreamsDatum
   * @param config InstagramConfiguration
   */
  public InstagramDataCollector(Instagram instagram, Queue<StreamsDatum> queue, InstagramConfiguration config) {
    this.dataQueue = queue;
    this.config = config;
    this.isCompleted = new AtomicBoolean(false);
    this.tokenManger = new BasicTokenManager<InstagramOAuthConfiguration>();
    this.consecutiveErrorCount = 0;
    this.backOffStrategy = new ExponentialBackOffStrategy(2);
    this.instagram = instagram;
  }


  /**
   * If there are authorized tokens available, it sets a new token for the client and returns
   * the client.  If there are no available tokens, it simply returns the client that was
   * initialized in the constructor with client id.
   * @return result
   */
  protected Instagram getNextInstagramClient() {
    //    if (this.tokenManger.numAvailableTokens() > 0) {
    //      this.instagram.setAccessToken(this.tokenManger.getNextAvailableToken());
    //    }
    return this.instagram;
  }

  /**
   * Return the number of available tokens for this data collector.
   * @return numbeer of available tokens
   */
  protected int numAvailableTokens() {
    return this.tokenManger.numAvailableTokens();
  }

  /**
   * Queues the Instagram data to be output by the provider.
   * @param userData data to queue
   * @param userId user id who the data came from
   */
  protected void queueData(Collection<T> userData, String userId) {
    if (userData == null) {
      LOGGER.warn("User id, {}, returned a NULL data from instagram.", userId);
    } else {
      for (T data : userData) {
        ComponentUtils.offerUntilSuccess(convertToStreamsDatum(data), this.dataQueue);
      }
    }
  }

  /**
   * @return true when the collector has queued all of the available Instagram data for the provided users.
   */
  public boolean isCompleted() {
    return this.isCompleted.get();
  }

  /**
   * Takes an Instagram Object and sets it as the document of a streams datum and sets the id of the streams datum.
   * @param item item
   * @return StreamsDatum
   */
  protected abstract StreamsDatum convertToStreamsDatum(T item);


}