package storm.starter;
import backtype.storm.Config;
import backtype.storm.LocalCluster;
import backtype.storm.coordination.BatchOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.testing.MemoryTransactionalSpout;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBatchBolt;
import backtype.storm.topology.base.BaseTransactionalBolt;
import backtype.storm.transactional.ICommitter;
import backtype.storm.transactional.TransactionAttempt;
import backtype.storm.transactional.TransactionalTopologyBuilder;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* This is a basic example of a transactional topology. It keeps a count of the number of tuples seen so far
* in a database. The source of data and the databases are mocked out as in memory maps for demonstration
* purposes. This class is defined in depth on the wiki at https://github.com/nathanmarz/storm/wiki/Transactional-topologies
*/
public class TransactionalGlobalCount {
public static final int PARTITION_TAKE_PER_BATCH = 3;
public static final Map<Integer, List<List<Object>>> DATA = new HashMap<Integer, List<List<Object>>>() {{
put(0, new ArrayList<List<Object>>() {{
add(new Values("cat"));
add(new Values("dog"));
add(new Values("chicken"));
add(new Values("cat"));
add(new Values("dog"));
add(new Values("apple"));
}});
put(1, new ArrayList<List<Object>>() {{
add(new Values("cat"));
add(new Values("dog"));
add(new Values("apple"));
add(new Values("banana"));
}});
put(2, new ArrayList<List<Object>>() {{
add(new Values("cat"));
add(new Values("cat"));
add(new Values("cat"));
add(new Values("cat"));
add(new Values("cat"));
add(new Values("dog"));
add(new Values("dog"));
add(new Values("dog"));
add(new Values("dog"));
}});
}};
public static class Value {
int count = 0;
BigInteger txid;
}
public static Map<String, Value> DATABASE = new HashMap<String, Value>();
public static final String GLOBAL_COUNT_KEY = "GLOBAL-COUNT";
public static class BatchCount extends BaseBatchBolt {
Object _id;
BatchOutputCollector _collector;
int _count = 0;
@Override
public void prepare(Map conf, TopologyContext context, BatchOutputCollector collector, Object id) {
_collector = collector;
_id = id;
}
@Override
public void execute(Tuple tuple) {
_count++;
}
@Override
public void finishBatch() {
_collector.emit(new Values(_id, _count));
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("id", "count"));
}
}
public static class UpdateGlobalCount extends BaseTransactionalBolt implements ICommitter {
TransactionAttempt _attempt;
BatchOutputCollector _collector;
int _sum = 0;
@Override
public void prepare(Map conf, TopologyContext context, BatchOutputCollector collector, TransactionAttempt attempt) {
_collector = collector;
_attempt = attempt;
}
@Override
public void execute(Tuple tuple) {
_sum+=tuple.getInteger(1);
}
@Override
public void finishBatch() {
Value val = DATABASE.get(GLOBAL_COUNT_KEY);
Value newval;
if(val == null || !val.txid.equals(_attempt.getTransactionId())) {
newval = new Value();
newval.txid = _attempt.getTransactionId();
if(val==null) {
newval.count = _sum;
} else {
newval.count = _sum + val.count;
}
DATABASE.put(GLOBAL_COUNT_KEY, newval);
} else {
newval = val;
}
_collector.emit(new Values(_attempt, newval.count));
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("id", "sum"));
}
}
public static void main(String[] args) throws Exception {
MemoryTransactionalSpout spout = new MemoryTransactionalSpout(DATA, new Fields("word"), PARTITION_TAKE_PER_BATCH);
TransactionalTopologyBuilder builder = new TransactionalTopologyBuilder("global-count", "spout", spout, 3);
builder.setBolt("partial-count", new BatchCount(), 5)
.noneGrouping("spout");
builder.setBolt("sum", new UpdateGlobalCount())
.globalGrouping("partial-count");
LocalCluster cluster = new LocalCluster();
Config config = new Config();
config.setDebug(true);
config.setMaxSpoutPending(3);
cluster.submitTopology("global-count-topology", config, builder.buildTopology());
Thread.sleep(3000);
cluster.shutdown();
}
}