[ARROW-17430] [Java] ListBinder to bind Arrow List type to DB column

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 10.0.0
• Fix Version/s: 10.0.0
• Component/s: Java
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/32698
• Assignee: Igor Suhorukov
• Reporter: Igor Suhorukov
• Created: 16/Aug/22 11:23
• Updated: 11/Jan/23 11:50
• Resolved: 19/Aug/22 12:09

Description

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]

 

  @Override
        
        
            public ColumnBinder visit(ArrowType.List type) {
        
        
              throw new UnsupportedOperationException("No column binder implemented for type " + type);
        
        
            } 

 

My current implementation patch ColumnBinderArrowTypeVisitor in classpath (to leverage Builder functionality instead of manual vector mapping in code) to return ListBinder

@Override
public ColumnBinder visit(ArrowType.List type) {
    return new ListBinder((ListVector) vector);
} 

and following code works for me with H2 database and in java stored PostgreSQL function in PL/Java to bind List parameter to JDBC:

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);
        }
    }
}
 

Issue Links

• is cloned by: ARROW-17431 [Java] MapBinder to bind Arrow Map type to DB column
• links to: GitHub Pull Request #13906