JdbcQueryWorker.java

/*
 * Copyright 2014-2015 the original author or authors
 *
 * Licensed 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.wplatform.ddal.excutor;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;

import javax.sql.DataSource;

import com.wplatform.ddal.engine.Session;
import com.wplatform.ddal.util.StatementBuilder;
import com.wplatform.ddal.value.Value;

/**
 * @author <a href="mailto:jorgie.mail@gmail.com">jorgie li</a>
 *
 */
public class JdbcQueryWorker extends JdbcWorker<ResultSet> {

    private final int maxrows;
    /**
     * @param session
     * @param shardName
     * @param sql
     * @param params
     */
    public JdbcQueryWorker(Session session, String shardName, String sql, List<Value> params,int maxrows) {
        super(session, shardName, sql, params);
        this.maxrows = maxrows;
    }

    @Override
    public ResultSet doWork() {
        Connection conn = null;
        PreparedStatement stmt = null;
        try {
            DataSource dataSource = getDataSource();
            Optional optional = Optional.build().shardName(shardName).readOnly(true);
            if (trace.isDebugEnabled()) {
                trace.debug("{0} Fetching connection from DataSource.", shardName);
            }
            conn = session.applyConnection(dataSource, optional);
            attach(conn);
            if (trace.isDebugEnabled()) {
                trace.debug("{0} Preparing: {};", shardName, sql);
            }
            stmt = conn.prepareStatement(sql);
            attach(stmt);
            applyQueryTimeout(stmt);
            applyMaxRows(stmt);
            
            if (params != null) {
                for (int i = 0, size = params.size(); i < size; i++) {
                    Value v = params.get(i);
                    v.set(stmt, i + 1);
                    if (trace.isDebugEnabled()) {
                        trace.debug("{0} setParameter: {1} -> {2};", shardName, i + 1, v.getSQL());
                    }
                }
            }
            ResultSet result = stmt.executeQuery();
            attach(result);
            return result;
        } catch (SQLException e) {
            StatementBuilder buff = new StatementBuilder();
            buff.append(shardName).append(" executing executeQuery error:").append(sql);
            if (params != null && params.size() > 0) {
                buff.append("\n{");
                int i = 1;
                for (Value v : params) {
                    buff.appendExceptFirst(", ");
                    buff.append(i++).append(": ").append(v.getSQL());
                }
                buff.append('}');
            }
            buff.append(';');
            trace.error(e, buff.toString());
            throw wrapException(sql, e);
        }
    }
    
    
    protected void applyMaxRows(Statement stmt) throws SQLException {
        int maxRows = maxrows > 0 ? maxrows : session.getDatabase().getMaxMemoryRows();
        stmt.setMaxRows(maxRows);
    }

}