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Apache HttpComponents Client
/*
* ====================================================================
* 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
* MultiThreadedHttpConnectionManager
* in HttpClient 3.x, see there for original authors. It implements the same
* algorithm for connection re-use and connection-per-host enforcement:
*
* - connections are re-used only for the exact same route
* - connection limits are enforced per route rather than per host
*
* Note that access to the pool data structures is synchronized via the
* {@link AbstractConnPool#poolLock poolLock} in the base class,
* not via synchronized methods.
*
* @since 4.0
*
* @deprecated (4.2) use {@link org.apache.http.pool.AbstractConnPool}
*/
@Deprecated
public class ConnPoolByRoute extends AbstractConnPool {
private final Log log = LogFactory.getLog(getClass());
private final Lock poolLock;
/** Connection operator for this pool */
protected final ClientConnectionOperator operator;
/** Connections per route lookup */
protected final ConnPerRoute connPerRoute;
/** References to issued connections */
protected final Set leasedConnections;
/** The list of free connections */
protected final Queue freeConnections;
/** The list of WaitingThreads waiting for a connection */
protected final Queue waitingThreads;
/** Map of route-specific pools */
protected final Map routeToPool;
private final long connTTL;
private final TimeUnit connTTLTimeUnit;
protected volatile boolean shutdown;
protected volatile int maxTotalConnections;
protected volatile int numConnections;
/**
* Creates a new connection pool, managed by route.
*
* @since 4.1
*/
public ConnPoolByRoute(
final ClientConnectionOperator operator,
final ConnPerRoute connPerRoute,
final int maxTotalConnections) {
this(operator, connPerRoute, maxTotalConnections, -1, TimeUnit.MILLISECONDS);
}
/**
* @since 4.1
*/
public ConnPoolByRoute(
final ClientConnectionOperator operator,
final ConnPerRoute connPerRoute,
final int maxTotalConnections,
final long connTTL,
final TimeUnit connTTLTimeUnit) {
super();
Args.notNull(operator, "Connection operator");
Args.notNull(connPerRoute, "Connections per route");
this.poolLock = super.poolLock;
this.leasedConnections = super.leasedConnections;
this.operator = operator;
this.connPerRoute = connPerRoute;
this.maxTotalConnections = maxTotalConnections;
this.freeConnections = createFreeConnQueue();
this.waitingThreads = createWaitingThreadQueue();
this.routeToPool = createRouteToPoolMap();
this.connTTL = connTTL;
this.connTTLTimeUnit = connTTLTimeUnit;
}
protected Lock getLock() {
return this.poolLock;
}
/**
* Creates a new connection pool, managed by route.
*
* @deprecated (4.1) use {@link ConnPoolByRoute#ConnPoolByRoute(ClientConnectionOperator, ConnPerRoute, int)}
*/
@Deprecated
public ConnPoolByRoute(final ClientConnectionOperator operator, final HttpParams params) {
this(operator,
ConnManagerParams.getMaxConnectionsPerRoute(params),
ConnManagerParams.getMaxTotalConnections(params));
}
/**
* Creates the queue for {@link #freeConnections}.
* Called once by the constructor.
*
* @return a queue
*/
protected Queue createFreeConnQueue() {
return new LinkedList();
}
/**
* Creates the queue for {@link #waitingThreads}.
* Called once by the constructor.
*
* @return a queue
*/
protected Queue createWaitingThreadQueue() {
return new LinkedList();
}
/**
* Creates the map for {@link #routeToPool}.
* Called once by the constructor.
*
* @return a map
*/
protected Map createRouteToPoolMap() {
return new HashMap();
}
/**
* Creates a new route-specific pool.
* Called by {@link #getRoutePool} when necessary.
*
* @param route the route
*
* @return the new pool
*/
protected RouteSpecificPool newRouteSpecificPool(final HttpRoute route) {
return new RouteSpecificPool(route, this.connPerRoute);
}
/**
* Creates a new waiting thread.
* Called by {@link #getRoutePool} when necessary.
*
* @param cond the condition to wait for
* @param rospl the route specific pool, or null
*
* @return a waiting thread representation
*/
protected WaitingThread newWaitingThread(final Condition cond,
final RouteSpecificPool rospl) {
return new WaitingThread(cond, rospl);
}
private void closeConnection(final BasicPoolEntry entry) {
final OperatedClientConnection conn = entry.getConnection();
if (conn != null) {
try {
conn.close();
} catch (final IOException ex) {
log.debug("I/O error closing connection", ex);
}
}
}
/**
* Get a route-specific pool of available connections.
*
* @param route the route
* @param create whether to create the pool if it doesn't exist
*
* @return the pool for the argument route,
* never null if create is true
*/
protected RouteSpecificPool getRoutePool(final HttpRoute route,
final boolean create) {
RouteSpecificPool rospl = null;
poolLock.lock();
try {
rospl = routeToPool.get(route);
if ((rospl == null) && create) {
// no pool for this route yet (or anymore)
rospl = newRouteSpecificPool(route);
routeToPool.put(route, rospl);
}
} finally {
poolLock.unlock();
}
return rospl;
}
public int getConnectionsInPool(final HttpRoute route) {
poolLock.lock();
try {
// don't allow a pool to be created here!
final RouteSpecificPool rospl = getRoutePool(route, false);
return (rospl != null) ? rospl.getEntryCount() : 0;
} finally {
poolLock.unlock();
}
}
public int getConnectionsInPool() {
poolLock.lock();
try {
return numConnections;
} finally {
poolLock.unlock();
}
}
@Override
public PoolEntryRequest requestPoolEntry(
final HttpRoute route,
final Object state) {
final WaitingThreadAborter aborter = new WaitingThreadAborter();
return new PoolEntryRequest() {
public void abortRequest() {
poolLock.lock();
try {
aborter.abort();
} finally {
poolLock.unlock();
}
}
public BasicPoolEntry getPoolEntry(
final long timeout,
final TimeUnit tunit)
throws InterruptedException, ConnectionPoolTimeoutException {
return getEntryBlocking(route, state, timeout, tunit, aborter);
}
};
}
/**
* Obtains a pool entry with a connection within the given timeout.
* If a {@link WaitingThread} is used to block, {@link WaitingThreadAborter#setWaitingThread(WaitingThread)}
* must be called before blocking, to allow the thread to be interrupted.
*
* @param route the route for which to get the connection
* @param timeout the timeout, 0 or negative for no timeout
* @param tunit the unit for the timeout,
* may be null only if there is no timeout
* @param aborter an object which can abort a {@link WaitingThread}.
*
* @return pool entry holding a connection for the route
*
* @throws ConnectionPoolTimeoutException
* if the timeout expired
* @throws InterruptedException
* if the calling thread was interrupted
*/
protected BasicPoolEntry getEntryBlocking(
final HttpRoute route, final Object state,
final long timeout, final TimeUnit tunit,
final WaitingThreadAborter aborter)
throws ConnectionPoolTimeoutException, InterruptedException {
Date deadline = null;
if (timeout > 0) {
deadline = new Date
(System.currentTimeMillis() + tunit.toMillis(timeout));
}
BasicPoolEntry entry = null;
poolLock.lock();
try {
RouteSpecificPool rospl = getRoutePool(route, true);
WaitingThread waitingThread = null;
while (entry == null) {
Asserts.check(!shutdown, "Connection pool shut down");
if (log.isDebugEnabled()) {
log.debug("[" + route + "] total kept alive: " + freeConnections.size() +
", total issued: " + leasedConnections.size() +
", total allocated: " + numConnections + " out of " + maxTotalConnections);
}
// the cases to check for:
// - have a free connection for that route
// - allowed to create a free connection for that route
// - can delete and replace a free connection for another route
// - need to wait for one of the things above to come true
entry = getFreeEntry(rospl, state);
if (entry != null) {
break;
}
final boolean hasCapacity = rospl.getCapacity() > 0;
if (log.isDebugEnabled()) {
log.debug("Available capacity: " + rospl.getCapacity()
+ " out of " + rospl.getMaxEntries()
+ " [" + route + "][" + state + "]");
}
if (hasCapacity && numConnections < maxTotalConnections) {
entry = createEntry(rospl, operator);
} else if (hasCapacity && !freeConnections.isEmpty()) {
deleteLeastUsedEntry();
// if least used entry's route was the same as rospl,
// rospl is now out of date : we preemptively refresh
rospl = getRoutePool(route, true);
entry = createEntry(rospl, operator);
} else {
if (log.isDebugEnabled()) {
log.debug("Need to wait for connection" +
" [" + route + "][" + state + "]");
}
if (waitingThread == null) {
waitingThread =
newWaitingThread(poolLock.newCondition(), rospl);
aborter.setWaitingThread(waitingThread);
}
boolean success = false;
try {
rospl.queueThread(waitingThread);
waitingThreads.add(waitingThread);
success = waitingThread.await(deadline);
} finally {
// In case of 'success', we were woken up by the
// connection pool and should now have a connection
// waiting for us, or else we're shutting down.
// Just continue in the loop, both cases are checked.
rospl.removeThread(waitingThread);
waitingThreads.remove(waitingThread);
}
// check for spurious wakeup vs. timeout
if (!success && (deadline != null) &&
(deadline.getTime() <= System.currentTimeMillis())) {
throw new ConnectionPoolTimeoutException
("Timeout waiting for connection from pool");
}
}
} // while no entry
} finally {
poolLock.unlock();
}
return entry;
}
@Override
public void freeEntry(final BasicPoolEntry entry, final boolean reusable, final long validDuration, final TimeUnit timeUnit) {
final HttpRoute route = entry.getPlannedRoute();
if (log.isDebugEnabled()) {
log.debug("Releasing connection" +
" [" + route + "][" + entry.getState() + "]");
}
poolLock.lock();
try {
if (shutdown) {
// the pool is shut down, release the
// connection's resources and get out of here
closeConnection(entry);
return;
}
// no longer issued, we keep a hard reference now
leasedConnections.remove(entry);
final RouteSpecificPool rospl = getRoutePool(route, true);
if (reusable && rospl.getCapacity() >= 0) {
if (log.isDebugEnabled()) {
final String s;
if (validDuration > 0) {
s = "for " + validDuration + " " + timeUnit;
} else {
s = "indefinitely";
}
log.debug("Pooling connection" +
" [" + route + "][" + entry.getState() + "]; keep alive " + s);
}
rospl.freeEntry(entry);
entry.updateExpiry(validDuration, timeUnit);
freeConnections.add(entry);
} else {
closeConnection(entry);
rospl.dropEntry();
numConnections--;
}
notifyWaitingThread(rospl);
} finally {
poolLock.unlock();
}
}
/**
* If available, get a free pool entry for a route.
*
* @param rospl the route-specific pool from which to get an entry
*
* @return an available pool entry for the given route, or
* null if none is available
*/
protected BasicPoolEntry getFreeEntry(final RouteSpecificPool rospl, final Object state) {
BasicPoolEntry entry = null;
poolLock.lock();
try {
boolean done = false;
while(!done) {
entry = rospl.allocEntry(state);
if (entry != null) {
if (log.isDebugEnabled()) {
log.debug("Getting free connection"
+ " [" + rospl.getRoute() + "][" + state + "]");
}
freeConnections.remove(entry);
if (entry.isExpired(System.currentTimeMillis())) {
// If the free entry isn't valid anymore, get rid of it
// and loop to find another one that might be valid.
if (log.isDebugEnabled()) {
log.debug("Closing expired free connection"
+ " [" + rospl.getRoute() + "][" + state + "]");
}
closeConnection(entry);
// We use dropEntry instead of deleteEntry because the entry
// is no longer "free" (we just allocated it), and deleteEntry
// can only be used to delete free entries.
rospl.dropEntry();
numConnections--;
} else {
leasedConnections.add(entry);
done = true;
}
} else {
done = true;
if (log.isDebugEnabled()) {
log.debug("No free connections"
+ " [" + rospl.getRoute() + "][" + state + "]");
}
}
}
} finally {
poolLock.unlock();
}
return entry;
}
/**
* Creates a new pool entry.
* This method assumes that the new connection will be handed
* out immediately.
*
* @param rospl the route-specific pool for which to create the entry
* @param op the operator for creating a connection
*
* @return the new pool entry for a new connection
*/
protected BasicPoolEntry createEntry(final RouteSpecificPool rospl,
final ClientConnectionOperator op) {
if (log.isDebugEnabled()) {
log.debug("Creating new connection [" + rospl.getRoute() + "]");
}
// the entry will create the connection when needed
final BasicPoolEntry entry = new BasicPoolEntry(op, rospl.getRoute(), connTTL, connTTLTimeUnit);
poolLock.lock();
try {
rospl.createdEntry(entry);
numConnections++;
leasedConnections.add(entry);
} finally {
poolLock.unlock();
}
return entry;
}
/**
* Deletes a given pool entry.
* This closes the pooled connection and removes all references,
* so that it can be GCed.
*
* Note: Does not remove the entry from the freeConnections list.
* It is assumed that the caller has already handled this step.
*
*
* @param entry the pool entry for the connection to delete
*/
protected void deleteEntry(final BasicPoolEntry entry) {
final HttpRoute route = entry.getPlannedRoute();
if (log.isDebugEnabled()) {
log.debug("Deleting connection"
+ " [" + route + "][" + entry.getState() + "]");
}
poolLock.lock();
try {
closeConnection(entry);
final RouteSpecificPool rospl = getRoutePool(route, true);
rospl.deleteEntry(entry);
numConnections--;
if (rospl.isUnused()) {
routeToPool.remove(route);
}
} finally {
poolLock.unlock();
}
}
/**
* Delete an old, free pool entry to make room for a new one.
* Used to replace pool entries with ones for a different route.
*/
protected void deleteLeastUsedEntry() {
poolLock.lock();
try {
final BasicPoolEntry entry = freeConnections.remove();
if (entry != null) {
deleteEntry(entry);
} else if (log.isDebugEnabled()) {
log.debug("No free connection to delete");
}
} finally {
poolLock.unlock();
}
}
@Override
protected void handleLostEntry(final HttpRoute route) {
poolLock.lock();
try {
final RouteSpecificPool rospl = getRoutePool(route, true);
rospl.dropEntry();
if (rospl.isUnused()) {
routeToPool.remove(route);
}
numConnections--;
notifyWaitingThread(rospl);
} finally {
poolLock.unlock();
}
}
/**
* Notifies a waiting thread that a connection is available.
* This will wake a thread waiting in the specific route pool,
* if there is one.
* Otherwise, a thread in the connection pool will be notified.
*
* @param rospl the pool in which to notify, or null
*/
protected void notifyWaitingThread(final RouteSpecificPool rospl) {
//@@@ while this strategy provides for best connection re-use,
//@@@ is it fair? only do this if the connection is open?
// Find the thread we are going to notify. We want to ensure that
// each waiting thread is only interrupted once, so we will remove
// it from all wait queues before interrupting.
WaitingThread waitingThread = null;
poolLock.lock();
try {
if ((rospl != null) && rospl.hasThread()) {
if (log.isDebugEnabled()) {
log.debug("Notifying thread waiting on pool" +
" [" + rospl.getRoute() + "]");
}
waitingThread = rospl.nextThread();
} else if (!waitingThreads.isEmpty()) {
if (log.isDebugEnabled()) {
log.debug("Notifying thread waiting on any pool");
}
waitingThread = waitingThreads.remove();
} else if (log.isDebugEnabled()) {
log.debug("Notifying no-one, there are no waiting threads");
}
if (waitingThread != null) {
waitingThread.wakeup();
}
} finally {
poolLock.unlock();
}
}
@Override
public void deleteClosedConnections() {
poolLock.lock();
try {
final Iterator iter = freeConnections.iterator();
while (iter.hasNext()) {
final BasicPoolEntry entry = iter.next();
if (!entry.getConnection().isOpen()) {
iter.remove();
deleteEntry(entry);
}
}
} finally {
poolLock.unlock();
}
}
/**
* Closes idle connections.
*
* @param idletime the time the connections should have been idle
* in order to be closed now
* @param tunit the unit for the idletime
*/
@Override
public void closeIdleConnections(final long idletime, final TimeUnit tunit) {
Args.notNull(tunit, "Time unit");
final long t = idletime > 0 ? idletime : 0;
if (log.isDebugEnabled()) {
log.debug("Closing connections idle longer than " + t + " " + tunit);
}
// the latest time for which connections will be closed
final long deadline = System.currentTimeMillis() - tunit.toMillis(t);
poolLock.lock();
try {
final Iterator iter = freeConnections.iterator();
while (iter.hasNext()) {
final BasicPoolEntry entry = iter.next();
if (entry.getUpdated() <= deadline) {
if (log.isDebugEnabled()) {
log.debug("Closing connection last used @ " + new Date(entry.getUpdated()));
}
iter.remove();
deleteEntry(entry);
}
}
} finally {
poolLock.unlock();
}
}
@Override
public void closeExpiredConnections() {
log.debug("Closing expired connections");
final long now = System.currentTimeMillis();
poolLock.lock();
try {
final Iterator iter = freeConnections.iterator();
while (iter.hasNext()) {
final BasicPoolEntry entry = iter.next();
if (entry.isExpired(now)) {
if (log.isDebugEnabled()) {
log.debug("Closing connection expired @ " + new Date(entry.getExpiry()));
}
iter.remove();
deleteEntry(entry);
}
}
} finally {
poolLock.unlock();
}
}
@Override
public void shutdown() {
poolLock.lock();
try {
if (shutdown) {
return;
}
shutdown = true;
// close all connections that are issued to an application
final Iterator iter1 = leasedConnections.iterator();
while (iter1.hasNext()) {
final BasicPoolEntry entry = iter1.next();
iter1.remove();
closeConnection(entry);
}
// close all free connections
final Iterator iter2 = freeConnections.iterator();
while (iter2.hasNext()) {
final BasicPoolEntry entry = iter2.next();
iter2.remove();
if (log.isDebugEnabled()) {
log.debug("Closing connection"
+ " [" + entry.getPlannedRoute() + "][" + entry.getState() + "]");
}
closeConnection(entry);
}
// wake up all waiting threads
final Iterator iwth = waitingThreads.iterator();
while (iwth.hasNext()) {
final WaitingThread waiter = iwth.next();
iwth.remove();
waiter.wakeup();
}
routeToPool.clear();
} finally {
poolLock.unlock();
}
}
/**
* since 4.1
*/
public void setMaxTotalConnections(final int max) {
poolLock.lock();
try {
maxTotalConnections = max;
} finally {
poolLock.unlock();
}
}
/**
* since 4.1
*/
public int getMaxTotalConnections() {
return maxTotalConnections;
}
}