PoolingDataSource.java
/*
* 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.tomcat.dbcp.dbcp2;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.logging.Logger;
import javax.sql.DataSource;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.dbcp.pool2.ObjectPool;
import org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool;
/**
* A simple {@link DataSource} implementation that obtains {@link Connection}s from the specified {@link ObjectPool}.
*
* @param <C>
* The connection type
*
* @since 2.0
*/
public class PoolingDataSource<C extends Connection> implements DataSource, AutoCloseable {
/**
* PoolGuardConnectionWrapper is a Connection wrapper that makes sure a closed connection cannot be used anymore.
*
* @since 2.0
*/
private final class PoolGuardConnectionWrapper<D extends Connection> extends DelegatingConnection<D> {
PoolGuardConnectionWrapper(final D delegate) {
super(delegate);
}
@Override
public void close() throws SQLException {
if (getDelegateInternal() != null) {
super.close();
super.setDelegate(null);
}
}
/**
* @see org.apache.tomcat.dbcp.dbcp2.DelegatingConnection#getDelegate()
*/
@Override
public D getDelegate() {
return isAccessToUnderlyingConnectionAllowed() ? super.getDelegate() : null;
}
/**
* @see org.apache.tomcat.dbcp.dbcp2.DelegatingConnection#getInnermostDelegate()
*/
@Override
public Connection getInnermostDelegate() {
return isAccessToUnderlyingConnectionAllowed() ? super.getInnermostDelegate() : null;
}
@Override
public boolean isClosed() throws SQLException {
return getDelegateInternal() == null || super.isClosed();
}
}
private static final Log log = LogFactory.getLog(PoolingDataSource.class);
/** Controls access to the underlying connection */
private boolean accessToUnderlyingConnectionAllowed;
/** My log writer. */
private PrintWriter logWriter;
private final ObjectPool<C> pool;
/**
* Constructs a new instance backed by the given connection pool.
*
* @param pool
* the given connection pool.
*/
public PoolingDataSource(final ObjectPool<C> pool) {
Objects.requireNonNull(pool, "Pool must not be null.");
this.pool = pool;
// Verify that pool's factory refers back to it. If not, log a warning and try to fix.
if (this.pool instanceof GenericObjectPool<?>) {
final PoolableConnectionFactory pcf = (PoolableConnectionFactory) ((GenericObjectPool<?>) this.pool)
.getFactory();
Objects.requireNonNull(pcf, "PoolableConnectionFactory must not be null.");
if (pcf.getPool() != this.pool) {
log.warn(Utils.getMessage("poolingDataSource.factoryConfig"));
@SuppressWarnings("unchecked") // PCF must have a pool of PCs
final ObjectPool<PoolableConnection> p = (ObjectPool<PoolableConnection>) this.pool;
pcf.setPool(p);
}
}
}
/**
* Closes and free all {@link Connection}s from the pool.
*
* @since 2.1
*/
@Override
public void close() throws SQLException {
try {
pool.close();
} catch (final Exception e) {
throw new SQLException(Utils.getMessage("pool.close.fail"), e);
}
}
/**
* Returns a {@link java.sql.Connection} from my pool, according to the contract specified by
* {@link ObjectPool#borrowObject}.
*/
@Override
public Connection getConnection() throws SQLException {
try {
final C conn = pool.borrowObject();
if (conn == null) {
return null;
}
return new PoolGuardConnectionWrapper<>(conn);
} catch (final NoSuchElementException e) {
throw new SQLException("Cannot get a connection, pool error " + e.getMessage(), e);
} catch (final SQLException | RuntimeException e) {
throw e;
} catch (final InterruptedException e) {
// Reset the interrupt status so it is visible to callers
Thread.currentThread().interrupt();
throw new SQLException("Cannot get a connection, general error", e);
} catch (final Exception e) {
throw new SQLException("Cannot get a connection, general error", e);
}
}
/**
* Throws {@link UnsupportedOperationException}
*
* @throws UnsupportedOperationException
* always thrown
*/
@Override
public Connection getConnection(final String userName, final String password) throws SQLException {
throw new UnsupportedOperationException();
}
// --- DataSource methods -----------------------------------------
/**
* 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.");
}
/**
* Returns my log writer.
*
* @return my log writer
* @see DataSource#getLogWriter
*/
@Override
public PrintWriter getLogWriter() {
return logWriter;
}
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
throw new SQLFeatureNotSupportedException();
}
protected ObjectPool<C> getPool() {
return pool;
}
/**
* Returns the value of the accessToUnderlyingConnectionAllowed property.
*
* @return true if access to the underlying {@link Connection} is allowed, false otherwise.
*/
public boolean isAccessToUnderlyingConnectionAllowed() {
return this.accessToUnderlyingConnectionAllowed;
}
@Override
public boolean isWrapperFor(final Class<?> iface) throws SQLException {
return iface != null && iface.isInstance(this);
}
/**
* 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(final boolean allow) {
this.accessToUnderlyingConnectionAllowed = allow;
}
/**
* Throws {@link UnsupportedOperationException}.
*
* @throws UnsupportedOperationException
* As this implementation does not support this feature.
*/
@Override
public void setLoginTimeout(final int seconds) {
throw new UnsupportedOperationException("Login timeout is not supported.");
}
/**
* Sets my log writer.
*
* @see DataSource#setLogWriter
*/
@Override
public void setLogWriter(final PrintWriter out) {
logWriter = out;
}
@Override
public <T> T unwrap(final Class<T> iface) throws SQLException {
if (isWrapperFor(iface)) {
return iface.cast(this);
}
throw new SQLException(this + " is not a wrapper for " + iface);
}
}