/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/impl/conn/SingleClientConnManager.java $
* $Revision: 673450 $
* $Date: 2008-07-02 10:35:05 -0700 (Wed, 02 Jul 2008) $
*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.impl.conn;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.ClientConnectionOperator;
import org.apache.http.conn.ClientConnectionRequest;
import org.apache.http.conn.ManagedClientConnection;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.conn.routing.RouteTracker;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.params.HttpParams;
/**
* A connection "manager" for a single connection.
* This manager is good only for single-threaded use.
* Allocation <i>always</i> returns the connection immediately,
* even if it has not been released after the previous allocation.
* In that case, a {@link #MISUSE_MESSAGE warning} is logged
* and the previously issued connection is revoked.
* <p>
* This class is derived from <code>SimpleHttpConnectionManager</code>
* in HttpClient 3. See there for original authors.
* </p>
*
* @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
* @author <a href="mailto:becke@u.washington.edu">Michael Becke</a>
*
*
* <!-- empty lines to avoid svn diff problems -->
* @version $Revision: 673450 $
*
* @since 4.0
*/
public class SingleClientConnManager implements ClientConnectionManager {
private final Log log = LogFactory.getLog(getClass());
/** The message to be logged on multiple allocation. */
public final static String MISUSE_MESSAGE =
"Invalid use of SingleClientConnManager: connection still allocated.\n" +
"Make sure to release the connection before allocating another one.";
/** The schemes supported by this connection manager. */
protected SchemeRegistry schemeRegistry;
/** The operator for opening and updating connections. */
protected ClientConnectionOperator connOperator;
/** The one and only entry in this pool. */
protected PoolEntry uniquePoolEntry;
/** The currently issued managed connection, if any. */
protected ConnAdapter managedConn;
/** The time of the last connection release, or -1. */
protected long lastReleaseTime;
/** The time the last released connection expires and shouldn't be reused. */
protected long connectionExpiresTime;
/** Whether the connection should be shut down on release. */
protected boolean alwaysShutDown;
/** Indicates whether this connection manager is shut down. */
protected volatile boolean isShutDown;
/**
* Creates a new simple connection manager.
*
* @param params the parameters for this manager
* @param schreg the scheme registry, or
* <code>null</code> for the default registry
*/
public SingleClientConnManager(HttpParams params,
SchemeRegistry schreg) {
if (schreg == null) {
throw new IllegalArgumentException
("Scheme registry must not be null.");
}
this.schemeRegistry = schreg;
this.connOperator = createConnectionOperator(schreg);
this.uniquePoolEntry = new PoolEntry();
this.managedConn = null;
this.lastReleaseTime = -1L;
this.alwaysShutDown = false; //@@@ from params? as argument?
this.isShutDown = false;
} // <constructor>
@Override
protected void finalize() throws Throwable {
shutdown();
super.finalize();
}
// non-javadoc, see interface ClientConnectionManager
public SchemeRegistry getSchemeRegistry() {
return this.schemeRegistry;
}
/**
* Hook for creating the connection operator.
* It is called by the constructor.
* Derived classes can override this method to change the
* instantiation of the operator.
* The default implementation here instantiates
* {@link DefaultClientConnectionOperator DefaultClientConnectionOperator}.
*
* @param schreg the scheme registry to use, or <code>null</code>
*
* @return the connection operator to use
*/
protected ClientConnectionOperator
createConnectionOperator(SchemeRegistry schreg) {
return new DefaultClientConnectionOperator(schreg);
}
/**
* Asserts that this manager is not shut down.
*
* @throws IllegalStateException if this manager is shut down
*/
protected final void assertStillUp()
throws IllegalStateException {
if (this.isShutDown)
throw new IllegalStateException("Manager is shut down.");
}
public final ClientConnectionRequest requestConnection(
final HttpRoute route,
final Object state) {
return new ClientConnectionRequest() {
public void abortRequest() {
// Nothing to abort, since requests are immediate.
}
public ManagedClientConnection getConnection(
long timeout, TimeUnit tunit) {
return SingleClientConnManager.this.getConnection(
route, state);
}
};
}
/**
* Obtains a connection.
* This method does not block.
*
* @param route where the connection should point to
*
* @return a connection that can be used to communicate
* along the given route
*/
public ManagedClientConnection getConnection(HttpRoute route, Object state) {
if (route == null) {
throw new IllegalArgumentException("Route may not be null.");
}
assertStillUp();
if (log.isDebugEnabled()) {
log.debug("Get connection for route " + route);
}
if (managedConn != null)
revokeConnection();
// check re-usability of the connection
boolean recreate = false;
boolean shutdown = false;
// Kill the connection if it expired.
closeExpiredConnections();
if (uniquePoolEntry.connection.isOpen()) {
RouteTracker tracker = uniquePoolEntry.tracker;
shutdown = (tracker == null || // can happen if method is aborted
!tracker.toRoute().equals(route));
} else {
// If the connection is not open, create a new PoolEntry,
// as the connection may have been marked not reusable,
// due to aborts -- and the PoolEntry should not be reused
// either. There's no harm in recreating an entry if
// the connection is closed.
recreate = true;
}
if (shutdown) {
recreate = true;
try {
uniquePoolEntry.shutdown();
} catch (IOException iox) {
log.debug("Problem shutting down connection.", iox);
}
}
if (recreate)
uniquePoolEntry = new PoolEntry();
managedConn = new ConnAdapter(uniquePoolEntry, route);
return managedConn;
}
// non-javadoc, see interface ClientConnectionManager
public void releaseConnection(ManagedClientConnection conn, long validDuration, TimeUnit timeUnit) {
assertStillUp();
if (!(conn instanceof ConnAdapter)) {
throw new IllegalArgumentException
("Connection class mismatch, " +
"connection not obtained from this manager.");
}
if (log.isDebugEnabled()) {
log.debug("Releasing connection " + conn);
}
ConnAdapter sca = (ConnAdapter) conn;
if (sca.poolEntry == null)
return; // already released
ClientConnectionManager manager = sca.getManager();
if (manager != null && manager != this) {
throw new IllegalArgumentException
("Connection not obtained from this manager.");
}
try {
// make sure that the response has been read completely
if (sca.isOpen() && (this.alwaysShutDown ||
!sca.isMarkedReusable())
) {
if (log.isDebugEnabled()) {
log.debug
("Released connection open but not reusable.");
}
// make sure this connection will not be re-used
// we might have gotten here because of a shutdown trigger
// shutdown of the adapter also clears the tracked route
sca.shutdown();
}
} catch (IOException iox) {
//@@@ log as warning? let pass?
if (log.isDebugEnabled())
log.debug("Exception shutting down released connection.",
iox);
} finally {
sca.detach();
managedConn = null;
lastReleaseTime = System.currentTimeMillis();
if(validDuration > 0)
connectionExpiresTime = timeUnit.toMillis(validDuration) + lastReleaseTime;
else
connectionExpiresTime = Long.MAX_VALUE;
}
} // releaseConnection
public void closeExpiredConnections() {
if(System.currentTimeMillis() >= connectionExpiresTime) {
closeIdleConnections(0, TimeUnit.MILLISECONDS);
}
}
// non-javadoc, see interface ClientConnectionManager
public void closeIdleConnections(long idletime, TimeUnit tunit) {
assertStillUp();
// idletime can be 0 or negative, no problem there
if (tunit == null) {
throw new IllegalArgumentException("Time unit must not be null.");
}
if ((managedConn == null) && uniquePoolEntry.connection.isOpen()) {
final long cutoff =
System.currentTimeMillis() - tunit.toMillis(idletime);
if (lastReleaseTime <= cutoff) {
try {
uniquePoolEntry.close();
} catch (IOException iox) {
// ignore
log.debug("Problem closing idle connection.", iox);
}
}
}
}
// non-javadoc, see interface ClientConnectionManager
public void shutdown() {
this.isShutDown = true;
if (managedConn != null)
managedConn.detach();
try {
if (uniquePoolEntry != null) // and connection open?
uniquePoolEntry.shutdown();
} catch (IOException iox) {
// ignore
log.debug("Problem while shutting down manager.", iox);
} finally {
uniquePoolEntry = null;
}
}
/**
* Revokes the currently issued connection.
* The adapter gets disconnected, the connection will be shut down.
*/
protected void revokeConnection() {
if (managedConn == null)
return;
log.warn(MISUSE_MESSAGE);
managedConn.detach();
try {
uniquePoolEntry.shutdown();
} catch (IOException iox) {
// ignore
log.debug("Problem while shutting down connection.", iox);
}
}
/**
* The pool entry for this connection manager.
*/
protected class PoolEntry extends AbstractPoolEntry {
/**
* Creates a new pool entry.
*
*/
protected PoolEntry() {
super(SingleClientConnManager.this.connOperator, null);
}
/**
* Closes the connection in this pool entry.
*/
protected void close()
throws IOException {
shutdownEntry();
if (connection.isOpen())
connection.close();
}
/**
* Shuts down the connection in this pool entry.
*/
protected void shutdown()
throws IOException {
shutdownEntry();
if (connection.isOpen())
connection.shutdown();
}
} // class PoolEntry
/**
* The connection adapter used by this manager.
*/
protected class ConnAdapter extends AbstractPooledConnAdapter {
/**
* Creates a new connection adapter.
*
* @param entry the pool entry for the connection being wrapped
* @param route the planned route for this connection
*/
protected ConnAdapter(PoolEntry entry, HttpRoute route) {
super(SingleClientConnManager.this, entry);
markReusable();
entry.route = route;
}
}
} // class SingleClientConnManager