Commons DBCP example source code file (PoolablePreparedStatement.java)

This example Commons DBCP source code file (PoolablePreparedStatement.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons DBCP tags/keywords

cannot, connection, delegatingpreparedstatement, jdbc, keyedobjectpool, object, object, poolablepreparedstatement, poolablepreparedstatement, preparedstatement, resultset, resultset, sql, sqlexception, sqlexception, sqlnestedexception, util

The Commons DBCP PoolablePreparedStatement.java source code

/*
 * 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.commons.dbcp;

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

import org.apache.commons.pool.KeyedObjectPool;

/**
 * A {@link DelegatingPreparedStatement} that cooperates with
 * {@link PoolingConnection} to implement a pool of {@link PreparedStatement}s.
 * <p>
 * My {@link #close} method returns me to my containing pool. (See {@link PoolingConnection}.)
 *
 * @see PoolingConnection
 * @author Rodney Waldhoff
 * @author Glenn L. Nielsen
 * @author James House
 * @author Dirk Verbeeck
 * @version $Revision: 745860 $ $Date: 2009-02-19 08:45:07 -0500 (Thu, 19 Feb 2009) $
 */
public class PoolablePreparedStatement extends DelegatingPreparedStatement implements PreparedStatement {
    /**
     * The {@link KeyedObjectPool} from which I was obtained.
     */
    protected KeyedObjectPool _pool = null;

    /**
     * My "key" as used by {@link KeyedObjectPool}.
     */
    protected Object _key = null;

    private volatile boolean batchAdded = false;

    /**
     * Constructor
     * @param stmt my underlying {@link PreparedStatement}
     * @param key my key" as used by {@link KeyedObjectPool}
     * @param pool the {@link KeyedObjectPool} from which I was obtained.
     * @param conn the {@link Connection} from which I was created
     */
    public PoolablePreparedStatement(PreparedStatement stmt, Object key, KeyedObjectPool pool, Connection conn) {
        super((DelegatingConnection) conn, stmt);
        _pool = pool;
        _key = key;

        // Remove from trace now because this statement will be 
        // added by the activate method.
        if(_conn != null) {
            _conn.removeTrace(this);
        }
    }

    /**
     * Add batch.
     */
    public void addBatch() throws SQLException {
        super.addBatch();
        batchAdded = true;
    }

    /**
     * Clear Batch.
     */
    public void clearBatch() throws SQLException {
        batchAdded = false;
        super.clearBatch();
    }

    /**
     * Return me to my pool.
     */
    public void close() throws SQLException {
        // calling close twice should have no effect
        if (!isClosed()) {
            try {
                _pool.returnObject(_key,this);
            } catch(SQLException e) {
                throw e;
            } catch(RuntimeException e) {
                throw e;
            } catch(Exception e) {
                throw new SQLNestedException("Cannot close preparedstatement (return to pool failed)", e);
            }
        }
    }
    
    protected void activate() throws SQLException{
        _closed = false;
        if(_conn != null) {
            _conn.addTrace(this);
        }
        super.activate();
    }
  
    protected void passivate() throws SQLException {
        _closed = true;
        if(_conn != null) {
            _conn.removeTrace(this);
        }

        // The JDBC spec requires that a statment close any open
        // ResultSet's when it is closed.
        // FIXME The PreparedStatement we're wrapping should handle this for us.
        // See bug 17301 for what could happen when ResultSets are closed twice.
        List resultSets = getTrace();
        if( resultSets != null) {
            ResultSet[] set = (ResultSet[]) resultSets.toArray(new ResultSet[resultSets.size()]);
            for (int i = 0; i < set.length; i++) {
                set[i].close();
            }
            clearTrace();
        }
        if (batchAdded) {
            clearBatch();
        }
        
        super.passivate();
    }

}