storm-client/src/jvm/org/apache/storm/task/OutputCollector.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.storm.task;

import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.utils.Utils;

/**
 * This output collector exposes the API for emitting tuples from an IRichBolt. This is the core API for emitting tuples. For a simpler API,
 * and a more restricted form of stream processing, see IBasicBolt and BasicOutputCollector.
 */
public class OutputCollector implements IOutputCollector {
    private IOutputCollector delegate;


    public OutputCollector(IOutputCollector delegate) {
        this.delegate = delegate;
    }

    /**
     * Emits a new tuple to a specific stream with a single anchor. The emitted values must be immutable.
     *
     * @param streamId the stream to emit to
     * @param anchor   the tuple to anchor to
     * @param tuple    the new output tuple from this bolt
     * @return the list of task ids that this new tuple was sent to
     */
    public List<Integer> emit(String streamId, Tuple anchor, List<Object> tuple) {
        return emit(streamId, Arrays.asList(anchor), tuple);
    }

    /**
     * Emits a new unanchored tuple to the specified stream. Because it's unanchored, if a failure happens downstream, this new tuple won't
     * affect whether any spout tuples are considered failed or not. The emitted values must be immutable.
     *
     * @param streamId the stream to emit to
     * @param tuple    the new output tuple from this bolt
     * @return the list of task ids that this new tuple was sent to
     */
    public List<Integer> emit(String streamId, List<Object> tuple) {
        return emit(streamId, (List) null, tuple);
    }

    /**
     * Emits a new tuple to the default stream anchored on a group of input tuples. The emitted values must be immutable.
     *
     * @param anchors the tuples to anchor to
     * @param tuple   the new output tuple from this bolt
     * @return the list of task ids that this new tuple was sent to
     */
    public List<Integer> emit(Collection<Tuple> anchors, List<Object> tuple) {
        return emit(Utils.DEFAULT_STREAM_ID, anchors, tuple);
    }


    /**
     * Emits a new tuple to the default stream anchored on a single tuple. The emitted values must be immutable.
     *
     * @param anchor the tuple to anchor to
     * @param tuple  the new output tuple from this bolt
     * @return the list of task ids that this new tuple was sent to
     */
    public List<Integer> emit(Tuple anchor, List<Object> tuple) {
        return emit(Utils.DEFAULT_STREAM_ID, anchor, tuple);
    }

    /**
     * Emits a new unanchored tuple to the default stream. Beacuse it's unanchored, if a failure happens downstream, this new tuple won't
     * affect whether any spout tuples are considered failed or not. The emitted values must be immutable.
     *
     * @param tuple the new output tuple from this bolt
     * @return the list of task ids that this new tuple was sent to
     */
    public List<Integer> emit(List<Object> tuple) {
        return emit(Utils.DEFAULT_STREAM_ID, tuple);
    }

    @Override
    public List<Integer> emit(String streamId, Collection<Tuple> anchors, List<Object> tuple) {
        return delegate.emit(streamId, anchors, tuple);
    }

    /**
     * Emits a tuple directly to the specified task id on the specified stream. If the target bolt does not subscribe to this bolt using a
     * direct grouping, the tuple will not be sent. If the specified output stream is not declared as direct, or the target bolt subscribes
     * with a non-direct grouping, an error will occur at runtime. The emitted values must be immutable.
     *
     * @param taskId   the taskId to send the new tuple to
     * @param streamId the stream to send the tuple on. It must be declared as a direct stream in the topology definition.
     * @param anchor   the tuple to anchor to
     * @param tuple    the new output tuple from this bolt
     */
    public void emitDirect(int taskId, String streamId, Tuple anchor, List<Object> tuple) {
        emitDirect(taskId, streamId, anchor == null ? (List) null : Arrays.asList(anchor), tuple);
    }

    /**
     * Emits a tuple directly to the specified task id on the specified stream. If the target bolt does not subscribe to this bolt using a
     * direct grouping, the tuple will not be sent. If the specified output stream is not declared as direct, or the target bolt subscribes
     * with a non-direct grouping, an error will occur at runtime. Note that this method does not use anchors, so downstream failures won't
     * affect the failure status of any spout tuples. The emitted values must be immutable.
     *
     * @param taskId   the taskId to send the new tuple to
     * @param streamId the stream to send the tuple on. It must be declared as a direct stream in the topology definition.
     * @param tuple    the new output tuple from this bolt
     */
    public void emitDirect(int taskId, String streamId, List<Object> tuple) {
        emitDirect(taskId, streamId, (List) null, tuple);
    }

    /**
     * Emits a tuple directly to the specified task id on the default stream. If the target bolt does not subscribe to this bolt using a
     * direct grouping, the tuple will not be sent. If the specified output stream is not declared as direct, or the target bolt subscribes
     * with a non-direct grouping, an error will occur at runtime. The emitted values must be immutable.
     *
     * <p>The default stream must be declared as direct in the topology definition. See OutputDeclarer#declare for how this is done when
     * defining topologies in Java.
     *
     * @param taskId  the taskId to send the new tuple to
     * @param anchors the tuples to anchor to
     * @param tuple   the new output tuple from this bolt
     */
    public void emitDirect(int taskId, Collection<Tuple> anchors, List<Object> tuple) {
        emitDirect(taskId, Utils.DEFAULT_STREAM_ID, anchors, tuple);
    }

    /**
     * Emits a tuple directly to the specified task id on the default stream. If the target bolt does not subscribe to this bolt using a
     * direct grouping, the tuple will not be sent. If the specified output stream is not declared as direct, or the target bolt subscribes
     * with a non-direct grouping, an error will occur at runtime. The emitted values must be immutable.
     *
     * <p>The default stream must be declared as direct in the topology definition. See OutputDeclarer#declare for how this is done when
     * defining topologies in Java.
     *
     * @param taskId the taskId to send the new tuple to
     * @param anchor the tuple to anchor to
     * @param tuple  the new output tuple from this bolt
     */
    public void emitDirect(int taskId, Tuple anchor, List<Object> tuple) {
        emitDirect(taskId, Utils.DEFAULT_STREAM_ID, anchor, tuple);
    }


    /**
     * Emits a tuple directly to the specified task id on the default stream. If the target bolt does not subscribe to this bolt using a
     * direct grouping, the tuple will not be sent. If the specified output stream is not declared as direct, or the target bolt subscribes
     * with a non-direct grouping, an error will occur at runtime. The emitted values must be immutable.
     *
     * <p>The default stream must be declared as direct in the topology definition. See OutputDeclarer#declare for how this is done when
     * defining topologies in Java.<
     *
     * <p>Note that this method does not use anchors, so downstream failures won't affect the failure status of any spout tuples.
     *
     * @param taskId the taskId to send the new tuple to
     * @param tuple  the new output tuple from this bolt
     */
    public void emitDirect(int taskId, List<Object> tuple) {
        emitDirect(taskId, Utils.DEFAULT_STREAM_ID, tuple);
    }

    @Override
    public void emitDirect(int taskId, String streamId, Collection<Tuple> anchors, List<Object> tuple) {
        delegate.emitDirect(taskId, streamId, anchors, tuple);
    }

    @Override
    public void ack(Tuple input) {
        delegate.ack(input);
    }

    @Override
    public void fail(Tuple input) {
        delegate.fail(input);
    }

    /**
     * Resets the message timeout for any tuple trees to which the given tuple belongs. The timeout is reset to
     * Config.TOPOLOGY_MESSAGE_TIMEOUT_SECS. Note that this is an expensive operation, and should be used sparingly.
     *
     * @param input the tuple to reset timeout for
     */
    @Override
    public void resetTimeout(Tuple input) {
        delegate.resetTimeout(input);
    }

    @Override
    public void reportError(Throwable error) {
        delegate.reportError(error);
    }

    @Override
    public void flush() {
        delegate.flush();
    }
}