Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * 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 * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.streams.twitter.processor; import com.fasterxml.jackson.databind.ObjectMapper; import com.google.common.collect.Lists; import org.apache.streams.config.StreamsConfigurator; import org.apache.streams.core.StreamsDatum; import org.apache.streams.core.StreamsProcessor; import org.apache.streams.exceptions.ActivitySerializerException; import org.apache.streams.pojo.json.Activity; import org.apache.streams.twitter.TwitterStreamConfiguration; import org.apache.streams.twitter.pojo.Delete; import org.apache.streams.twitter.pojo.Retweet; import org.apache.streams.twitter.pojo.Tweet; import org.apache.streams.twitter.provider.TwitterConfigurator; import org.apache.streams.twitter.provider.TwitterEventClassifier; import org.apache.streams.twitter.serializer.StreamsTwitterMapper; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import twitter4j.*; import twitter4j.conf.ConfigurationBuilder; import java.util.List; import static org.apache.streams.twitter.serializer.util.TwitterActivityUtil.*; /** * Given an Activity, fetches the tweet by the activity object id and replaces the existing activity with the converted activity * from what is returned by the twitter API. */ public class FetchAndReplaceTwitterProcessor implements StreamsProcessor { private static final String PROVIDER_ID = getProvider().getId(); private static final Logger LOGGER = LoggerFactory.getLogger(FetchAndReplaceTwitterProcessor.class); //Default number of attempts before allowing the document through private static final int MAX_ATTEMPTS = 5; //Start the backoff at 4 minutes. This results in a wait period of 4, 8, 12, 16 & 20 min with an attempt of 5 public static final int BACKOFF = 1000 * 60 * 4; private final TwitterStreamConfiguration config; private Twitter client; private ObjectMapper mapper; private int retryCount; public FetchAndReplaceTwitterProcessor() { this(TwitterConfigurator.detectTwitterStreamConfiguration(StreamsConfigurator.config.getConfig("twitter"))); } public FetchAndReplaceTwitterProcessor(TwitterStreamConfiguration config) { this.config = config; } @Override public List<StreamsDatum> process(StreamsDatum entry) { if (entry.getDocument() instanceof Activity) { Activity doc = (Activity) entry.getDocument(); String originalId = doc.getId(); if (PROVIDER_ID.equals(doc.getProvider().getId())) { fetchAndReplace(doc, originalId); } } else { throw new IllegalStateException("Requires an activity document"); } return Lists.newArrayList(entry); } @Override public void prepare(Object configurationObject) { this.client = getTwitterClient(); this.mapper = StreamsTwitterMapper.getInstance(); } @Override public void cleanUp() { } protected void fetchAndReplace(Activity doc, String originalId) { try { String json = fetch(doc); replace(doc, json); doc.setId(originalId); retryCount = 0; } catch (TwitterException tw) { if (tw.exceededRateLimitation()) { sleepAndTryAgain(doc, originalId); } } catch (Exception e) { LOGGER.warn("Error fetching and replacing tweet for activity {}", doc.getId()); } } protected void replace(Activity doc, String json) throws java.io.IOException, ActivitySerializerException { Class documentSubType = TwitterEventClassifier.detectClass(json); Object object = mapper.readValue(json, documentSubType); if (documentSubType.equals(Retweet.class) || documentSubType.equals(Tweet.class)) { updateActivity((Tweet) object, doc); } else if (documentSubType.equals(Delete.class)) { updateActivity((Delete) object, doc); } else { LOGGER.info("Could not determine the correct update method for {}", documentSubType); } } protected String fetch(Activity doc) throws TwitterException { String id = doc.getObject().getId(); LOGGER.debug("Fetching status from Twitter for {}", id); Long tweetId = Long.valueOf(id.replace("id:twitter:tweets:", "")); Status status = getTwitterClient().showStatus(tweetId); return TwitterObjectFactory.getRawJSON(status); } protected Twitter getTwitterClient() { if (this.client == null) { String baseUrl = "https://api.twitter.com:443/1.1/"; ConfigurationBuilder builder = new ConfigurationBuilder() .setOAuthConsumerKey(config.getOauth().getConsumerKey()) .setOAuthConsumerSecret(config.getOauth().getConsumerSecret()) .setOAuthAccessToken(config.getOauth().getAccessToken()) .setOAuthAccessTokenSecret(config.getOauth().getAccessTokenSecret()) .setIncludeEntitiesEnabled(true).setJSONStoreEnabled(true).setAsyncNumThreads(1) .setRestBaseURL(baseUrl).setIncludeMyRetweetEnabled(Boolean.TRUE) .setPrettyDebugEnabled(Boolean.TRUE); this.client = new TwitterFactory(builder.build()).getInstance(); } return this.client; } //Hardcore sleep to allow for catch up protected void sleepAndTryAgain(Activity doc, String originalId) { try { //Attempt to fetchAndReplace with a backoff up to the limit then just reset the count and let the process continue if (retryCount < MAX_ATTEMPTS) { retryCount++; LOGGER.debug("Sleeping for {} min due to excessive calls to Twitter API", (retryCount * 4)); Thread.sleep(BACKOFF * retryCount); fetchAndReplace(doc, originalId); } else { retryCount = 0; } } catch (InterruptedException e) { LOGGER.warn("Thread sleep interrupted while waiting for twitter backoff"); } } }