apex-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From chinmaykolhatkar <...@git.apache.org>
Subject [GitHub] incubator-apex-malhar pull request: APEXMALHAR-2015: Projection Op...
Date Mon, 21 Mar 2016 10:56:08 GMT
Github user chinmaykolhatkar commented on a diff in the pull request:

    https://github.com/apache/incubator-apex-malhar/pull/217#discussion_r56805377
  
    --- Diff: library/src/main/java/com/datatorrent/lib/projection/ProjectionOperator.java
---
    @@ -0,0 +1,303 @@
    +/**
    + * 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.projection;
    +
    +import java.lang.reflect.Field;
    +
    +import java.util.ArrayList;
    +import java.util.Arrays;
    +import java.util.List;
    +
    +import org.slf4j.Logger;
    +import org.slf4j.LoggerFactory;
    +
    +import org.apache.commons.lang3.ClassUtils;
    +
    +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.util.PojoUtils;
    +
    +/**
    + * <b>ProjectionOperator</b>
    + * Projection Operator projects defined set of fields from given selectFields/dropFields
    + *
    + * <b>Parameters</b>
    + * - selectFields: comma separated list of fields to be selected from input tuples
    + * - dropFields: comma separated list of fields to be dropped from input tuples
    + * selectFields and dropFields are optional and either of them shall be specified
    + * When both are not specified, all fields shall be projected to downstream operator
    + *
    + * <b>Input Port</b> takes POJOs as an input
    + *
    + * <b>Output Ports</b>
    + * - projected port emits POJOs with projected fields from input POJOs
    + * - remainder port, if connected, emits POJOs with remainder fields from input POJOs
    + * - error port emits input POJOs as is upon error situations
    + * 
    + * <b>Examples</b>
    + * For {a, b, c} type of input tuples
    + *  - when selectFields = "" and dropFields = "", projected port shall emit {a, b, c}
    + *  - when selectFields = "b", projected port shall emit {b} and remainder port shall
emit {a, c}
    + *  - when dropFields = "b", projected port shall emit {a, c} and remainder port shall
emit {b}
    + * 
    + */
    +
    +public class ProjectionOperator extends BaseOperator implements Operator.ActivationListener<Context>
    +{
    +  protected String selectFields;
    +  protected String dropFields;
    +  protected String condition;
    +
    +  static class TypeInfo
    +  {
    +    String name;
    +    Class type;
    +    PojoUtils.Setter setter;
    +    PojoUtils.Getter getter;
    +
    +    public TypeInfo(String name, Class<?> type)
    +    {
    +      this.name = name;
    +      this.type = type;
    +    }
    +
    +    public String toString()
    +    {
    +      String s = new String("'name': " + name + " 'type': " + type);
    +      return s;
    +    }
    +  }
    +
    +  protected transient List<TypeInfo> projectedFields = new ArrayList<>();
    --- End diff --
    
    Unless there is a immediate need for a projectedFields & remainderFields to be used
by subclass, I'll suggest to make these fields private.


---
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