Commons DBCP example source code file (PoolableConnection.java)

This example Commons DBCP source code file (PoolableConnection.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

abandonedconfig, already, cannot, delegatingconnection, exception, jdbc, objectpool, objectpool, poolableconnection, poolableconnection, sql, sqlexception, sqlexception, xxx, xxx

The Commons DBCP PoolableConnection.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.SQLException;
import org.apache.commons.pool.ObjectPool;

/**
 * A delegating connection that, rather than closing the underlying
 * connection, returns itself to an {@link ObjectPool} when
 * closed.
 *
 * @author Rodney Waldhoff
 * @author Glenn L. Nielsen
 * @author James House
 * @version $Revision: 758745 $ $Date: 2009-03-26 13:02:20 -0400 (Thu, 26 Mar 2009) $
 */
public class PoolableConnection extends DelegatingConnection {
    /** The pool to which I should return. */
    // TODO: Correct use of the pool requires that this connection is only every returned to the pool once.
    protected ObjectPool _pool = null;

    /**
     *
     * @param conn my underlying connection
     * @param pool the pool to which I should return when closed
     */
    public PoolableConnection(Connection conn, ObjectPool pool) {
        super(conn);
        _pool = pool;
    }

    /**
     *
     * @param conn my underlying connection
     * @param pool the pool to which I should return when closed
     * @param config the abandoned configuration settings
     */
    public PoolableConnection(Connection conn, ObjectPool pool, AbandonedConfig config) {
        super(conn, config);
        _pool = pool;
    }


    /**
     * Returns me to my pool.
     */
     public synchronized void close() throws SQLException {
        if (_closed) {
            // already closed
            return;
        }

        boolean isUnderlyingConectionClosed;
        try {
            isUnderlyingConectionClosed = _conn.isClosed();
        } catch (SQLException e) {
            try {
                _pool.invalidateObject(this); // XXX should be guarded to happen at most once
            } catch(IllegalStateException ise) {
                // pool is closed, so close the connection
                passivate();
                getInnermostDelegate().close();
            } catch (Exception ie) {
                // DO NOTHING the original exception will be rethrown
            }
            throw (SQLException) new SQLException("Cannot close connection (isClosed check failed)").initCause(e);
        }

        if (!isUnderlyingConectionClosed) {
            // Normal close: underlying connection is still open, so we
            // simply need to return this proxy to the pool
            try {
                _pool.returnObject(this); // XXX should be guarded to happen at most once
            } catch(IllegalStateException e) {
                // pool is closed, so close the connection
                passivate();
                getInnermostDelegate().close();
            } catch(SQLException e) {
                throw e;
            } catch(RuntimeException e) {
                throw e;
            } catch(Exception e) {
                throw (SQLException) new SQLException("Cannot close connection (return to pool failed)").initCause(e);
            }
        } else {
            // Abnormal close: underlying connection closed unexpectedly, so we
            // must destroy this proxy
            try {
                _pool.invalidateObject(this); // XXX should be guarded to happen at most once
            } catch(IllegalStateException e) {
                // pool is closed, so close the connection
                passivate();
                getInnermostDelegate().close();
            } catch (Exception ie) {
                // DO NOTHING, "Already closed" exception thrown below
            }
            throw new SQLException("Already closed.");
        }
    }

    /**
     * Actually close my underlying {@link Connection}.
     */
    public void reallyClose() throws SQLException {
        super.close();
    }
}