apex-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From gauravgopi123 <...@git.apache.org>
Subject [GitHub] incubator-apex-malhar pull request: MLHR-1936 Adding NiFi operator...
Date Fri, 18 Dec 2015 22:37:21 GMT
Github user gauravgopi123 commented on a diff in the pull request:

    https://github.com/apache/incubator-apex-malhar/pull/133#discussion_r48077817
  
    --- Diff: contrib/src/main/java/com/datatorrent/contrib/nifi/AbstractNiFiInputOperator.java
---
    @@ -0,0 +1,162 @@
    +/**
    + * 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 com.datatorrent.contrib.nifi;
    +
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.List;
    +
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import org.apache.nifi.remote.Transaction;
    +import org.apache.nifi.remote.TransferDirection;
    +import org.apache.nifi.remote.client.SiteToSiteClient;
    +import org.apache.nifi.remote.protocol.DataPacket;
    +
    +import com.datatorrent.api.Context;
    +import com.datatorrent.api.InputOperator;
    +
    +/**
    + * This is the base implementation of a NiFi input operator.&nbsp;
    + * Subclasses should implement the methods which convert NiFi DataPackets to tuples and
emit them.
    + * <p>
    + * Ports:<br>
    + * <b>Input</b>: No input port<br>
    + * <b>Output</b>: Can have any number of output ports<br>
    + * <br>
    + * Properties:<br>
    + * None<br>
    + * <br>
    + * Compile time checks:<br>
    + * Classes derived from this have to implement the abstract methods emitTuples(List<T>
tuples)&nbsp;
    + * and createTuple(DataPacket dp)<br>
    + * <br>
    + * Run time checks:<br>
    + * None<br>
    + * <br>
    + * Benchmarks:<br>
    + * TBD<br>
    + * </p>
    + *
    + * @displayName Abstract NiFi Input
    + * @category Messaging
    + * @tags input operator
    + * @since 3.3.0
    + */
    +
    +public abstract class AbstractNiFiInputOperator<T> implements InputOperator
    +{
    +
    +  private static final Logger LOGGER = LoggerFactory.getLogger(AbstractNiFiInputOperator.class);
    +
    +  private SiteToSiteClient client;
    +  private final SiteToSiteClient.Builder siteToSiteBuilder;
    +
    +  /**
    +   * @param siteToSiteBuilder the builder for a NiFi SiteToSiteClient
    +   */
    +  public AbstractNiFiInputOperator(final SiteToSiteClient.Builder siteToSiteBuilder)
    +  {
    +    this.siteToSiteBuilder = siteToSiteBuilder;
    +  }
    +
    +  @Override
    +  public void setup(Context.OperatorContext context)
    +  {
    +    this.client = siteToSiteBuilder.build();
    +  }
    +
    +  @Override
    +  public void teardown()
    +  {
    +    try {
    +      client.close();
    +    } catch (IOException e) {
    +      LOGGER.error(e.getMessage(), e);
    +    }
    +  }
    +
    +  @Override
    +  public void emitTuples()
    +  {
    +    try {
    +      final Transaction transaction = client.createTransaction(TransferDirection.RECEIVE);
    +      if (transaction == null) {
    +        LOGGER.warn("A transaction could not be created, returning...");
    +        return;
    +      }
    +
    +      DataPacket dataPacket = transaction.receive();
    +      if (dataPacket == null) {
    +        transaction.confirm();
    +        transaction.complete();
    +        LOGGER.debug("No data available to pull, returning and will try again...");
    +        return;
    +      }
    +
    +      // read all of the available data packets and convert to the given type
    +      final List<T> tuples = new ArrayList<>();
    +      do {
    +        tuples.add(createTuple(dataPacket));
    +        dataPacket = transaction.receive();
    +      } while (dataPacket != null);
    --- End diff --
    
    can this lead to infinite loop? May be you want to add number of DataPacket condition
as well?


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message