apex-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (APEXMALHAR-2082) Data Filter Operator
Date Tue, 17 May 2016 09:43:12 GMT

    [ https://issues.apache.org/jira/browse/APEXMALHAR-2082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15286303#comment-15286303
] 

ASF GitHub Bot commented on APEXMALHAR-2082:
--------------------------------------------

Github user pradeepdalvi commented on a diff in the pull request:

    https://github.com/apache/incubator-apex-malhar/pull/270#discussion_r63492795
  
    --- Diff: library/src/main/java/com/datatorrent/lib/filter/FilterOperator.java ---
    @@ -0,0 +1,177 @@
    +/**
    + * 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.lib.filter;
    +
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import org.apache.hadoop.classification.InterfaceStability;
    +
    +import com.google.common.annotations.VisibleForTesting;
    +
    +import com.datatorrent.api.AutoMetric;
    +import com.datatorrent.api.Context;
    +import com.datatorrent.api.Context.PortContext;
    +import com.datatorrent.api.DefaultInputPort;
    +import com.datatorrent.api.DefaultOutputPort;
    +
    +import com.datatorrent.api.Operator;
    +import com.datatorrent.api.annotation.InputPortFieldAnnotation;
    +import com.datatorrent.api.annotation.OutputPortFieldAnnotation;
    +
    +import com.datatorrent.common.util.BaseOperator;
    +import com.datatorrent.lib.expression.Expression;
    +import com.datatorrent.lib.util.PojoUtils;
    +
    +/**
    + * <b>FilterOperator</b>
    + * Filter Operator filter out tuples based on defined condition
    + *
    + * <b>Parameters</b>
    + * - condition: condition based on expression langugage
    + *
    + * <b>Input Port</b> takes POJOs as an input
    + *
    + * <b>Output Ports</b>
    + * - truePort emits POJOs meeting the given condition
    + * - falsePort emits POJOs not meeting the given condition
    + * - error port emits any error situation while evaluating expression
    + * 
    + */
    +@InterfaceStability.Evolving
    +public class FilterOperator extends BaseOperator implements Operator.ActivationListener
    +{
    +  protected String condition;
    +
    +  protected Class<?> inClazz = null;
    +
    +  private Expression<Boolean> expr = null;
    +
    +  @AutoMetric
    +  protected long trueTuples;
    +
    +  @AutoMetric
    +  protected long falseTuples;
    +
    +  @AutoMetric
    +  protected long errorTuples;
    +
    +  @InputPortFieldAnnotation(schemaRequired = true)
    +  public transient DefaultInputPort<Object> input = new DefaultInputPort<Object>()
    +  {
    +    public void setup(PortContext context)
    +    {
    +      inClazz = context.getValue(Context.PortContext.TUPLE_CLASS);
    +    }
    +
    +    @Override
    +    public void process(Object t)
    +    {
    +      processTuple(t);
    +    }
    +  };
    +
    +  @OutputPortFieldAnnotation(schemaRequired = true)
    +  public final transient DefaultOutputPort<Object> truePort = new DefaultOutputPort<Object>();
    +
    +  @OutputPortFieldAnnotation(schemaRequired = true)
    +  public final transient DefaultOutputPort<Object> falsePort = new DefaultOutputPort<Object>();
    +
    +  @OutputPortFieldAnnotation(schemaRequired = true)
    +  public final transient DefaultOutputPort<Object> error = new DefaultOutputPort<Object>();
    +
    +  @Override
    +  public void activate(Context context)
    +  {
    +    createExpression();
    +  }
    +
    +  @Override
    +  public void deactivate()
    +  {
    +    expr = null;
    +  }
    +
    +  @Override
    +  public void beginWindow(long windowId)
    +  {
    +    errorTuples = trueTuples = falseTuples = 0;
    +  }
    +
    +  /**
    +   * createExpression: create an expression from condition of POJO fields
    +   * Override this function for custom field expressions
    +   */
    +  protected void createExpression()
    +  {
    +    logger.info("Creating an expression for condition {}", condition);
    +    expr = PojoUtils.createExpression(inClazz, condition, Boolean.class);
    +  }
    +
    +  /**
    +   * evalExpression: Evaluate condition/expression
    +   * Override this function for custom condition evaluation
    +   */
    +  protected Boolean evalExpression(Object t)
    +  {
    +    return expr.execute(t);
    +  }
    +
    +  /**
    +   * handleFilter: emit POJO meeting condition on truePort
    +   * and if it did not meet condition then on falsePort
    +   */
    +  private void processTuple(Object t)
    +  {
    +    try {
    +      if (evalExpression(t)) {
    +        truePort.emit(t);
    +        trueTuples++;
    +      } else {
    +        falsePort.emit(t);
    +        falseTuples++;
    +      }
    +    } catch (Exception ex) {
    +      logger.error("Error in expression eval: {}", ex.getMessage());
    +      logger.debug("Exception: ", ex);
    --- End diff --
    
    Basically the idea is to limit extended error messages in data path. This exception is
on incorrect tuples, hence stacktrace would probably fill logs quickly if we start hitting
the issue and make it hard to analyze debug logs. Hence we have added single line message
in error and if required entire stacktrace can be retrieved in debug mode.


> Data Filter Operator 
> ---------------------
>
>                 Key: APEXMALHAR-2082
>                 URL: https://issues.apache.org/jira/browse/APEXMALHAR-2082
>             Project: Apache Apex Malhar
>          Issue Type: New Feature
>            Reporter: Pradeep A Dalvi
>
> Data Filter Operator which will allow apex users to filter (select/drop) tuples based
on the certain condition from incoming stream.
> Use case:
> -------------
> In many cases, not all tuples are of interest for the downstream operators. In such cases,
one may want select/filter out tuples to downstream. Also one may want to process tuples which
did not meet the condition/expression.
> Functionality:
> -----------------
> 1. Any tuple for which expression could not be evaluated shall be emitted on error output
port.
> 2. Filter operator shall receive POJO as input tuple and emit POJO on either of remaining
output ports i.e. truePort and falsePort. As the output ports' name signify, when condition
is met then the POJO shall be emitted on truePort and if condition is not met then that POJO
shall be emitted on falsePort.
> 3. Operator needs condition/expression as a input param. This condition is based on expression
language support we already have in Malhar.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message