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Apache Commons DBCP software implements Database Connection Pooling
/*
* 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.dbcp2;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.NoSuchElementException;
import java.util.logging.Logger;
import javax.sql.DataSource;
import org.apache.commons.pool2.ObjectPool;
/**
* A simple {@link DataSource} implementation that obtains
* {@link Connection}s from the specified {@link ObjectPool}.
*
* @param The connection type
*
* @author Rodney Waldhoff
* @author Glenn L. Nielsen
* @author James House
* @author Dirk Verbeeck
* @version $Revision: 1572244 $ $Date: 2014-02-26 20:38:08 +0000 (Wed, 26 Feb 2014) $
* @since 2.0
*/
public class PoolingDataSource implements DataSource {
/** Controls access to the underlying connection */
private boolean accessToUnderlyingConnectionAllowed = false;
public PoolingDataSource(ObjectPool pool) {
if (null == pool) {
throw new NullPointerException("Pool must not be null.");
}
_pool = pool;
}
/**
* Returns the value of the accessToUnderlyingConnectionAllowed property.
*
* @return true if access to the underlying is allowed, false otherwise.
*/
public boolean isAccessToUnderlyingConnectionAllowed() {
return this.accessToUnderlyingConnectionAllowed;
}
/**
* Sets the value of the accessToUnderlyingConnectionAllowed property.
* It controls if the PoolGuard allows access to the underlying connection.
* (Default: false)
*
* @param allow Access to the underlying connection is granted when true.
*/
public void setAccessToUnderlyingConnectionAllowed(boolean allow) {
this.accessToUnderlyingConnectionAllowed = allow;
}
/* JDBC_4_ANT_KEY_BEGIN */
@Override
public boolean isWrapperFor(Class iface) throws SQLException {
return false;
}
@Override
public T unwrap(Class iface) throws SQLException {
throw new SQLException("PoolingDataSource is not a wrapper.");
}
/* JDBC_4_ANT_KEY_END */
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
throw new SQLFeatureNotSupportedException();
}
//--- DataSource methods -----------------------------------------
/**
* Return a {@link java.sql.Connection} from my pool,
* according to the contract specified by {@link ObjectPool#borrowObject}.
*/
@Override
public Connection getConnection() throws SQLException {
try {
C conn = _pool.borrowObject();
if (conn == null) {
return null;
}
return new PoolGuardConnectionWrapper<>(conn);
} catch(SQLException e) {
throw e;
} catch(NoSuchElementException e) {
throw new SQLException("Cannot get a connection, pool error " + e.getMessage(), e);
} catch(RuntimeException e) {
throw e;
} catch(Exception e) {
throw new SQLException("Cannot get a connection, general error", e);
}
}
/**
* Throws {@link UnsupportedOperationException}
* @throws UnsupportedOperationException
*/
@Override
public Connection getConnection(String uname, String passwd) throws SQLException {
throw new UnsupportedOperationException();
}
/**
* Returns my log writer.
* @return my log writer
* @see DataSource#getLogWriter
*/
@Override
public PrintWriter getLogWriter() {
return _logWriter;
}
/**
* Throws {@link UnsupportedOperationException}.
* @throws UnsupportedOperationException As this
* implementation does not support this feature.
*/
@Override
public int getLoginTimeout() {
throw new UnsupportedOperationException("Login timeout is not supported.");
}
/**
* Throws {@link UnsupportedOperationException}.
* @throws UnsupportedOperationException As this
* implementation does not support this feature.
*/
@Override
public void setLoginTimeout(int seconds) {
throw new UnsupportedOperationException("Login timeout is not supported.");
}
/**
* Sets my log writer.
* @see DataSource#setLogWriter
*/
@Override
public void setLogWriter(PrintWriter out) {
_logWriter = out;
}
/** My log writer. */
private PrintWriter _logWriter = null;
private final ObjectPool _pool;
protected ObjectPool getPool() {
return _pool;
}
/**
* PoolGuardConnectionWrapper is a Connection wrapper that makes sure a
* closed connection cannot be used anymore.
* @since 2.0
*/
private class PoolGuardConnectionWrapper
extends DelegatingConnection {
PoolGuardConnectionWrapper(D delegate) {
super(delegate);
}
/**
* @see org.apache.commons.dbcp2.DelegatingConnection#getDelegate()
*/
@Override
public D getDelegate() {
if (isAccessToUnderlyingConnectionAllowed()) {
return super.getDelegate();
}
return null;
}
/**
* @see org.apache.commons.dbcp2.DelegatingConnection#getInnermostDelegate()
*/
@Override
public Connection getInnermostDelegate() {
if (isAccessToUnderlyingConnectionAllowed()) {
return super.getInnermostDelegate();
}
return null;
}
@Override
public void close() throws SQLException {
if (getDelegateInternal() != null) {
super.close();
super.setDelegate(null);
}
}
@Override
public boolean isClosed() throws SQLException {
if (getDelegateInternal() == null) {
return true;
}
return super.isClosed();
}
}
}