test-apps/twitter-counter/src/main/java/org/apache/s4/example/twitter/TwitterCounterApp.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.s4.example.twitter;

import java.util.List;
import java.util.concurrent.TimeUnit;

import org.apache.s4.base.KeyFinder;
import org.apache.s4.core.App;
import org.apache.s4.core.Stream;
import org.apache.s4.core.ft.CheckpointingConfig;
import org.apache.s4.core.ft.CheckpointingConfig.CheckpointingMode;

import com.google.common.collect.ImmutableList;

public class TwitterCounterApp extends App {

    @Override
    protected void onClose() {
    }

    @Override
    protected void onInit() {
        try {

            TopNTopicPE topNTopicPE = createPE(TopNTopicPE.class);
            topNTopicPE.setTimerInterval(10, TimeUnit.SECONDS);
            // we checkpoint this PE every 20s
            topNTopicPE.setCheckpointingConfig(new CheckpointingConfig.Builder(CheckpointingMode.TIME).frequency(20)
                    .timeUnit(TimeUnit.SECONDS).build());
            @SuppressWarnings("unchecked")
            Stream<TopicEvent> aggregatedTopicStream = createStream("AggregatedTopicSeen", new KeyFinder<TopicEvent>() {

                @Override
                public List<String> get(final TopicEvent arg0) {
                    return ImmutableList.of("aggregationKey");
                }
            }, topNTopicPE);

            TopicCountAndReportPE topicCountAndReportPE = createPE(TopicCountAndReportPE.class);
            topicCountAndReportPE.setDownstream(aggregatedTopicStream);
            topicCountAndReportPE.setTimerInterval(10, TimeUnit.SECONDS);
            // we checkpoint instances every 2 events
            topicCountAndReportPE.setCheckpointingConfig(new CheckpointingConfig.Builder(CheckpointingMode.EVENT_COUNT)
                    .frequency(2).build());
            Stream<TopicEvent> topicSeenStream = createStream("TopicSeen", new KeyFinder<TopicEvent>() {

                @Override
                public List<String> get(final TopicEvent arg0) {
                    return ImmutableList.of(arg0.getTopic());
                }
            }, topicCountAndReportPE);

            TopicExtractorPE topicExtractorPE = createPE(TopicExtractorPE.class);
            topicExtractorPE.setDownStream(topicSeenStream);
            topicExtractorPE.setSingleton(true);
            createInputStream("RawStatus", topicExtractorPE);

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    protected void onStart() {

    }
}