[jira] [Assigned] (ARROW-17430) [Java] ListBinder to bind Arrow List type to DB column

["David Li (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-17430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Li reassigned ARROW-17430:
--------------------------------

    Assignee: Igor Suhorukov

> [Java] ListBinder to bind Arrow List type to DB column 
> -------------------------------------------------------
>
>                 Key: ARROW-17430
>                 URL: https://issues.apache.org/jira/browse/ARROW-17430
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: Java
>    Affects Versions: 10.0.0
>            Reporter: Igor Suhorukov
>            Assignee: Igor Suhorukov
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 2h
>  Remaining Estimate: 0h
>
> Typical real life Arrow datasets contain List type vectors of primitive type. Looks logically implement default JDBC parameter binders for such vector type or implement some kind on binder code extensibility of core framework via MetaINF/ServiceLocator
> Current implementation just [throws UnsupportedOperationException|#L80]]
>  
> {code:java}
>   @Override
>         
>         
>             public ColumnBinder visit(ArrowType.List type) {
>         
>         
>               throw new UnsupportedOperationException("No column binder implemented for type " + type);
>         
>         
>             } {code}
>  
> My current implementation patch {color:#000000}ColumnBinderArrowTypeVisitor in classpath (to leverage Builder functionality instead of manual vector mapping in code) to return ListBinder{color}
> {code:java}
> @Override
> public ColumnBinder visit(ArrowType.List type) {
>     return new ListBinder((ListVector) vector);
> } {code}
> {color:#000000}and following code works for me with H2 database and in java stored PostgreSQL {color}{color:#000000}function in PL/Java to bind List parameter to JDBC:{color}
> {code:java}
> package org.apache.arrow.adapter.jdbc.binder;
> import org.apache.arrow.vector.complex.ListVector;
> import org.apache.arrow.vector.complex.impl.UnionListReader;
> import java.sql.PreparedStatement;
> import java.sql.SQLException;
> import java.sql.Types;
> import java.util.ArrayList;
> import java.util.Arrays;
> public class ListBinder extends BaseColumnBinder<ListVector>{
>     private UnionListReader reader;
>     public ListBinder(ListVector vector) {
>         this(vector, Types.ARRAY);
>     }
>     public ListBinder(ListVector vector, int jdbcType) {
>         super(vector, jdbcType);
>         reader = vector.getReader();
>     }
>     @Override
>     public void bind(PreparedStatement statement, int parameterIndex, int rowIndex) throws SQLException {
>         reader.setPosition(rowIndex);
>         ArrayList sourceArray = (ArrayList) reader.readObject();
>         Class aClass = sourceArray.get(0).getClass();
>         if(aClass.isAssignableFrom(Long.class)){
>             Long[] res = new Long[sourceArray.size()];
>             Arrays.setAll(res, sourceArray::get);
>             statement.setObject(parameterIndex, res);
>         } else
>         if(aClass.isAssignableFrom(Integer.class)){
>             Integer[] res = new Integer[sourceArray.size()];
>             Arrays.setAll(res, sourceArray::get);
>             statement.setObject(parameterIndex, res);
>         } else
>         if(aClass.isAssignableFrom(Short.class)){
>             Short[] res = new Short[sourceArray.size()];
>             Arrays.setAll(res, sourceArray::get);
>             statement.setObject(parameterIndex, res);
>         } else
>         if(aClass.isAssignableFrom(String.class)){
>             String[] res = new String[sourceArray.size()];
>             Arrays.setAll(res, sourceArray::get);
>             statement.setObject(parameterIndex, res);
>         }
>     }
> }
>  {code}



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