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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (APEXMALHAR-2023) Adding Enrichment Operator to Malhar
Date Mon, 25 Apr 2016 12:11:12 GMT

    [ https://issues.apache.org/jira/browse/APEXMALHAR-2023?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15256264#comment-15256264
] 

ASF GitHub Bot commented on APEXMALHAR-2023:
--------------------------------------------

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

    https://github.com/apache/incubator-apex-malhar/pull/235#discussion_r60902381
  
    --- Diff: contrib/src/main/java/com/datatorrent/contrib/enrich/JDBCLoader.java ---
    @@ -0,0 +1,201 @@
    +/**
    + * 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.enrich;
    +
    +import java.sql.PreparedStatement;
    +import java.sql.ResultSet;
    +import java.sql.ResultSetMetaData;
    +import java.sql.SQLException;
    +import java.util.ArrayList;
    +import java.util.List;
    +import java.util.Map;
    +
    +import org.apache.commons.collections.CollectionUtils;
    +import org.apache.hadoop.classification.InterfaceStability;
    +
    +import com.google.common.collect.Lists;
    +import com.datatorrent.lib.db.jdbc.JdbcStore;
    +import com.datatorrent.lib.util.FieldInfo;
    +
    +/**
    + * <p>HBaseLoader extends from {@link JdbcStore} uses JDBC to connect and implements
BackendLoaders interface.</p> <br/>
    + * <p>
    + * Properties:<br>
    + * <b>queryStmt</b>: Sql Prepared Statement which needs to be executed<br>
    + * <b>tableName</b>: JDBC table name<br>
    + * <br>
    + */
    +@InterfaceStability.Evolving
    +public class JDBCLoader extends JdbcStore implements BackendLoader
    +{
    +  protected String queryStmt;
    +
    +  protected String tableName;
    +
    +  protected transient List<FieldInfo> includeFieldInfo;
    +  protected transient List<FieldInfo> lookupFieldInfo;
    +
    +  protected Object getQueryResult(Object key)
    +  {
    +    try {
    +      PreparedStatement getStatement = getConnection().prepareStatement(queryStmt);
    +      ArrayList<Object> keys = (ArrayList<Object>)key;
    +      for (int i = 0; i < keys.size(); i++) {
    +        getStatement.setObject(i + 1, keys.get(i));
    +      }
    +      return getStatement.executeQuery();
    +    } catch (SQLException e) {
    +      throw new RuntimeException(e);
    +    }
    +  }
    +
    +  protected ArrayList<Object> getDataFrmResult(Object result) throws RuntimeException
    +  {
    +    try {
    +      ResultSet resultSet = (ResultSet)result;
    +      if (resultSet.next()) {
    +        ResultSetMetaData rsdata = resultSet.getMetaData();
    +        // If the includefields is empty, populate it from ResultSetMetaData
    +        if (CollectionUtils.isEmpty(includeFieldInfo)) {
    +          if (includeFieldInfo == null) {
    +            includeFieldInfo = new ArrayList<>();
    +          }
    +          for (int i = 1; i <= rsdata.getColumnCount(); i++) {
    +            String columnName = rsdata.getColumnName(i);
    +            // TODO: Take care of type conversion.
    +            includeFieldInfo.add(new FieldInfo(columnName, columnName, FieldInfo.SupportType.OBJECT));
    +          }
    +        }
    +
    +        ArrayList<Object> res = new ArrayList<Object>();
    +        for (FieldInfo f : includeFieldInfo) {
    +          res.add(getConvertedData(resultSet.getObject(f.getColumnName()), f));
    +        }
    +        return res;
    +      } else {
    +        return null;
    +      }
    +    } catch (SQLException e) {
    +      throw new RuntimeException(e);
    +    }
    +  }
    +
    +  private Object getConvertedData(Object object, FieldInfo f)
    +  {
    +    if (f.getType().getJavaType() == object.getClass()) {
    +      return object;
    +    } else {
    +      logger.warn("Type mismatch seen for field {}, returning as it is", f.getColumnName());
    +      return null;
    +    }
    +  }
    +
    +  private String generateQueryStmt()
    +  {
    +    String stmt = "select * from " + tableName + " where ";
    +    boolean first = true;
    +    for (FieldInfo fieldInfo : lookupFieldInfo) {
    +      if (first) {
    +        first = false;
    +      } else {
    +        stmt += " and ";
    +      }
    +      stmt += fieldInfo.getColumnName() + " = ?";
    +    }
    +
    +    logger.info("generateQueryStmt: {}", stmt);
    +    return stmt;
    +  }
    +
    +  public String getQueryStmt()
    +  {
    +    return queryStmt;
    +  }
    +
    +  /**
    +   * Set the sql Prepared Statement if the enrichment mechanism is query based.
    +   */
    +  public void setQueryStmt(String queryStmt)
    +  {
    +    this.queryStmt = queryStmt;
    +  }
    +
    +  public String getTableName()
    +  {
    +    return tableName;
    +  }
    +
    +  /**
    +   * Set the table name.
    +   */
    +  public void setTableName(String tableName)
    +  {
    +    this.tableName = tableName;
    +  }
    +
    +  @Override
    +  public void setFieldInfo(List<FieldInfo> lookupFieldInfo, List<FieldInfo>
includeFieldInfo)
    +  {
    +    this.lookupFieldInfo = lookupFieldInfo;
    +    this.includeFieldInfo = includeFieldInfo;
    +    if (queryStmt == null) {
    +      queryStmt = generateQueryStmt();
    +    }
    +  }
    +
    +  @Override
    +  public Map<Object, Object> loadInitialData()
    +  {
    +    return null;
    --- End diff --
    
    I'm not sure if this is the best use of loadInitialData here.
    If one wants, this loader can be extended to override this method.


> Adding Enrichment Operator to Malhar
> ------------------------------------
>
>                 Key: APEXMALHAR-2023
>                 URL: https://issues.apache.org/jira/browse/APEXMALHAR-2023
>             Project: Apache Apex Malhar
>          Issue Type: New Feature
>          Components: adapters database
>    Affects Versions: 3.3.1
>            Reporter: Chinmay Kolhatkar
>            Assignee: Chinmay Kolhatkar
>
> Add Enrichment Operator to Apex Malhar.
> Discussion is happening in mailing list here:
> http://mail-archives.apache.org/mod_mbox/incubator-apex-dev/201603.mbox/%3CCAKJfLDMo24-Gcvum2ZL8-0JOnE8QLryAy0Zu_R5zhMd_bsJyHw%40mail.gmail.com%3E
> Ponymail permalink:
> https://pony-poc.apache.org/thread.html/Z8t5ut5pu5vprgt



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