一、作用
Partition Spout对应的executor
二、源码分析
package storm.trident.spout;
import backtype.storm.task.TopologyContext;
import backtype.storm.tuple.Fields;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import storm.trident.operation.TridentCollector;
import storm.trident.topology.TransactionAttempt;
import storm.trident.topology.state.RotatingTransactionalState;
import storm.trident.topology.state.TransactionalState;
// PartitionedTridentSpout的执行器
public class PartitionedTridentSpoutExecutor implements ITridentSpout<Integer> {
// 内置一个spout对象
IPartitionedTridentSpout _spout;
public PartitionedTridentSpoutExecutor(IPartitionedTridentSpout spout) {
_spout = spout;
}
public IPartitionedTridentSpout getPartitionedSpout() {
return _spout;
}
//
class Coordinator implements ITridentSpout.BatchCoordinator<Object> {
// 协调器
private IPartitionedTridentSpout.Coordinator _coordinator;
public Coordinator(Map conf, TopologyContext context) {
_coordinator = _spout.getCoordinator(conf, context);
}
// 若是当前的metadata为空则直接返回batch的partitions
// 否则返回当前的metadata
@Override
public Object initializeTransaction(long txid, Object prevMetadata, Object currMetadata) {
if (currMetadata != null) {
return currMetadata;
} else {
return _coordinator.getPartitionsForBatch();
}
}
// 关闭协调器
@Override
public void close() {
_coordinator.close();
}
// 协调成功操作
@Override
public void success(long txid) {
}
// 指定的事务是否准备ok
@Override
public boolean isReady(long txid) {
return _coordinator.isReady(txid);
}
}
// 静态内部类 emit的状态类
static class EmitterPartitionState {
// transaction state
public RotatingTransactionalState rotatingState;
// spout partiton
public ISpoutPartition partition;
public EmitterPartitionState(RotatingTransactionalState s, ISpoutPartition p) {
rotatingState = s;
partition = p;
}
}
// emit的操作
class Emitter implements ITridentSpout.Emitter<Object> {
// emit
private IPartitionedTridentSpout.Emitter _emitter;
// 事务
private TransactionalState _state;
// partition transaction state
private Map<String, EmitterPartitionState> _partitionStates = new HashMap<String, EmitterPartitionState>();
// emit索引
private int _index;
// task 的总数
private int _numTasks;
public Emitter(String txStateId, Map conf, TopologyContext context) {
_emitter = _spout.getEmitter(conf, context);
_state = TransactionalState.newUserState(conf, txStateId);
_index = context.getThisTaskIndex();
_numTasks = context.getComponentTasks(context.getThisComponentId()).size();
}
// 记录coordinator的meta data
Object _savedCoordinatorMeta = null;
// 若是本地缓存的coordinator的meta数据为空或者和指定coordinatorMeta不同 则直接重新获取partitions
// 同时清空原有的partition state
// 根据原有的索引 遍历partitions : 1、本地缓存 2、refresh partitions 3、更新本地coordinator
@Override
public void emitBatch(final TransactionAttempt tx, final Object coordinatorMeta, final TridentCollector collector) {
if (_savedCoordinatorMeta == null || !_savedCoordinatorMeta.equals(coordinatorMeta)) {
List<ISpoutPartition> partitions = _emitter.getOrderedPartitions(coordinatorMeta);
_partitionStates.clear();
List<ISpoutPartition> myPartitions = new ArrayList();
for (int i = _index; i < partitions.size(); i += _numTasks) {
ISpoutPartition p = partitions.get(i);
String id = p.getId();
myPartitions.add(p);
_partitionStates.put(id, new EmitterPartitionState(new RotatingTransactionalState(_state, id), p));
}
_emitter.refreshPartitions(myPartitions);
_savedCoordinatorMeta = coordinatorMeta;
}
for (EmitterPartitionState s : _partitionStates.values()) {
RotatingTransactionalState state = s.rotatingState;
final ISpoutPartition partition = s.partition;
Object meta = state.getStateOrCreate(tx.getTransactionId(), new RotatingTransactionalState.StateInitializer() {
@Override
public Object init(long txid, Object lastState) {
return _emitter.emitPartitionBatchNew(tx, collector, partition, lastState);
}
});
// it's null if one of:
// a) a later transaction batch was emitted before this, so we should skip this batch
// b) if didn't exist and was created (in which case the StateInitializer was invoked and
// it was emitted
if (meta != null) {
_emitter.emitPartitionBatch(tx, collector, partition, meta);
}
}
}
// 提供成功的操作
@Override
public void success(TransactionAttempt tx) {
for (EmitterPartitionState state : _partitionStates.values()) {
state.rotatingState.cleanupBefore(tx.getTransactionId());
}
}
// 关闭state 和 emit
@Override
public void close() {
_state.close();
_emitter.close();
}
}
@Override
public ITridentSpout.BatchCoordinator getCoordinator(String txStateId, Map conf, TopologyContext context) {
return new Coordinator(conf, context);
}
@Override
public ITridentSpout.Emitter getEmitter(String txStateId, Map conf, TopologyContext context) {
return new Emitter(txStateId, conf, context);
}
@Override
public Map<String, Object> getComponentConfiguration() {
return _spout.getComponentConfiguration();
}
@Override
public Fields getOutputFields() {
return _spout.getOutputFields();
}
}
jstorm源码之PartitionedTridentSpoutExecutor
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转载自dalan-123.iteye.com/blog/2285259
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