org.apache.mahout.cf.taste.impl.model.jdbc.ConnectionPoolDataSource.java Source code

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Here is the source code for org.apache.mahout.cf.taste.impl.model.jdbc.ConnectionPoolDataSource.java

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/**
 * 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 org.apache.mahout.cf.taste.impl.model.jdbc;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;

import javax.sql.DataSource;

import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.PoolingDataSource;
import org.apache.commons.pool.impl.GenericObjectPool;

import com.google.common.base.Preconditions;

/**
 * <p>
 * A wrapper {@link DataSource} which pools connections.
 * </p>
 */
public final class ConnectionPoolDataSource implements DataSource {

    private final DataSource delegate;

    public ConnectionPoolDataSource(DataSource underlyingDataSource) {
        Preconditions.checkNotNull(underlyingDataSource);
        ConnectionFactory connectionFactory = new ConfiguringConnectionFactory(underlyingDataSource);
        GenericObjectPool objectPool = new GenericObjectPool();
        objectPool.setTestOnBorrow(false);
        objectPool.setTestOnReturn(false);
        objectPool.setTestWhileIdle(true);
        objectPool.setTimeBetweenEvictionRunsMillis(60 * 1000L);
        // Constructor actually sets itself as factory on pool
        new PoolableConnectionFactory(connectionFactory, objectPool, null, "SELECT 1", false, false);
        delegate = new PoolingDataSource(objectPool);
    }

    @Override
    public Connection getConnection() throws SQLException {
        return delegate.getConnection();
    }

    @Override
    public Connection getConnection(String username, String password) throws SQLException {
        return delegate.getConnection(username, password);
    }

    @Override
    public PrintWriter getLogWriter() throws SQLException {
        return delegate.getLogWriter();
    }

    @Override
    public void setLogWriter(PrintWriter printWriter) throws SQLException {
        delegate.setLogWriter(printWriter);
    }

    @Override
    public void setLoginTimeout(int timeout) throws SQLException {
        delegate.setLoginTimeout(timeout);
    }

    @Override
    public int getLoginTimeout() throws SQLException {
        return delegate.getLoginTimeout();
    }

    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        return delegate.unwrap(iface);
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        return delegate.isWrapperFor(iface);
    }

    // This exists for compatibility with Java 7 / JDBC 4.1, but doesn't exist
    // in Java 6. In Java 7 it would @Override, but not in 6.
    // @Override
    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
        throw new SQLFeatureNotSupportedException();
    }

    private static class ConfiguringConnectionFactory implements ConnectionFactory {

        private final DataSource underlyingDataSource;

        ConfiguringConnectionFactory(DataSource underlyingDataSource) {
            this.underlyingDataSource = underlyingDataSource;
        }

        @Override
        public Connection createConnection() throws SQLException {
            Connection connection = underlyingDataSource.getConnection();
            connection.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED);
            connection.setHoldability(ResultSet.CLOSE_CURSORS_AT_COMMIT);
            return connection;
        }
    }

}