RedshiftのUNLOADコマンドをDomaで生成する案

AppConfig.java

package sample;

public class AppConfig implements Config {

    @Override
    public QueryImplementors getQueryImplementors() {
        return new QueryImplementors() {
            @Override
            public SqlFileSelectQuery createSqlFileSelectQuery(Method method) {
                if (method.isAnnotationPresent(Unload.class)) {
                    return new UnloadQuery();
                }
                return QueryImplementors.super.createSqlFileSelectQuery(method);
            }
        };
    }
}

DataLog.java

package sample;

import org.seasar.doma.Entity;

@Entity
public class DataLog {
    public String hoge;
    public String foo;
    public String bar;
}

DataLogDao.java

package sample;

import java.time.LocalDateTime;
import java.util.List;

import org.seasar.doma.Dao;
import org.seasar.doma.Select;

@Dao
public interface DataLogDao {

    @Unload
    @Select
    List<DataLog> unload(LocalDateTime startAt, LocalDateTime endAt,
            String s3bucket, String accessKey, String sercretKey);
}

Unload.java

package sample;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Unload {
}

unload.sql

SELECT 
  hoge,foo,bar
FROM
  data_log_table
WHERE
  created_at BETWEEN /* startAt */'2016-11-01 10:00:00' AND /* endAt */'2016-11-01 11:00:00'

/*%if s3bucket == null && accessKey == null && sercretKey == null *//*%end*/

UnloadQuery.java

package sample;

import java.util.List;
import java.util.function.BiFunction;
import java.util.function.Function;

import org.seasar.doma.internal.expr.ExpressionEvaluator;
import org.seasar.doma.internal.jdbc.sql.PreparedSql;
import org.seasar.doma.internal.jdbc.sql.node.ExpandNode;
import org.seasar.doma.jdbc.query.SqlFileSelectQuery;

public class UnloadQuery extends SqlFileSelectQuery {

    @Override
    protected void buildSql(
            BiFunction<ExpressionEvaluator, Function<ExpandNode, List<String>>, PreparedSql> sqlBuilder) {
        super.buildSql(sqlBuilder);
        sql = new PreparedSql(sql.getKind(),
                buildUnloadStatement(sql.getRawSql()),
                buildUnloadStatement(sql.getFormattedSql()),
                sql.getSqlFilePath(), sql.getParameters(), sql.getSqlLogType());
    }

    protected String buildUnloadStatement(String sql) {
        String s3bucket = (String) parameters.get("s3bucket").getValue();
        String accessKey = (String) parameters.get("accessKey").getValue();
        String sercretKey = (String) parameters.get("sercretKey").getValue();
        return String
                .format("unload ('%s') to '%s' credentials 'aws_access_key_id=%s;aws_secret_access_key=%s' parallel off",
                        sql, s3bucket, accessKey, sercretKey);
    }
}