asterixdb/asterix-external-data/src/main/java/org/apache/asterix/external/input/record/reader/twitter/TwitterPushRecordReader.java

/*
 * 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.asterix.external.input.record.reader.twitter;

import java.io.IOException;
import java.util.concurrent.LinkedBlockingQueue;

import org.apache.asterix.external.api.IRawRecord;
import org.apache.asterix.external.api.IRecordReader;
import org.apache.asterix.external.dataflow.AbstractFeedDataFlowController;
import org.apache.asterix.external.input.record.CharArrayRecord;
import org.apache.asterix.external.util.IFeedLogManager;
import org.apache.asterix.external.util.TwitterUtil;

import twitter4j.FilterQuery;
import twitter4j.TwitterStream;

public class TwitterPushRecordReader implements IRecordReader<char[]> {
    private LinkedBlockingQueue<String> inputQ;
    private TwitterStream twitterStream;
    private CharArrayRecord record;
    private boolean closed = false;

    public TwitterPushRecordReader(TwitterStream twitterStream, TwitterUtil.TweetListener tweetListener,
            FilterQuery query) {
        init(twitterStream);
        tweetListener.setInputQ(inputQ);
        this.twitterStream.addListener(tweetListener);
        this.twitterStream.filter(query);
    }

    public TwitterPushRecordReader(TwitterStream twitterStream, TwitterUtil.TweetListener tweetListener) {
        init(twitterStream);
        tweetListener.setInputQ(inputQ);
        this.twitterStream.addListener(tweetListener);
        twitterStream.sample();
    }

    public TwitterPushRecordReader(TwitterStream twitterStream, TwitterUtil.UserTweetsListener tweetListener) {
        init(twitterStream);
        tweetListener.setInputQ(inputQ);
        this.twitterStream.addListener(tweetListener);
        twitterStream.user();
    }

    private void init(TwitterStream twitterStream) {
        record = new CharArrayRecord();
        inputQ = new LinkedBlockingQueue<>();
        this.twitterStream = twitterStream;
    }

    @Override
    public void close() throws IOException {
        if (!closed) {
            twitterStream.clearListeners();
            twitterStream.cleanUp();
            twitterStream = null;
            closed = true;
        }
    }

    @Override
    public boolean hasNext() throws Exception {
        return !closed;
    }

    @Override
    public IRawRecord<char[]> next() throws IOException, InterruptedException {
        String tweet = inputQ.poll();
        if (tweet == null) {
            return null;
        }
        record.set(tweet);
        return record;
    }

    @Override
    public boolean stop() {
        try {
            close();
        } catch (Exception e) {
            return false;
        }
        return true;
    }

    @Override
    public void setFeedLogManager(IFeedLogManager feedLogManager) {
        // do nothing
    }

    @Override
    public void setController(AbstractFeedDataFlowController controller) {
        // do nothing
    }

    @Override
    public boolean handleException(Throwable th) {
        return false;
    }
}