Package org.apache.http.impl.conn.tsccm

Class ConnPoolByRoute

java.lang.Object

org.apache.http.impl.conn.tsccm.AbstractConnPool

org.apache.http.impl.conn.tsccm.ConnPoolByRoute

All Implemented Interfaces:

RefQueueHandler

public class ConnPoolByRoute
extends AbstractConnPool

A connection pool that maintains connections by route. This class is derived from 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 datastructures is synchronized via the poolLock in the base class, not via synchronized methods.

Author:

Roland Weber, Michael Becke, and others

Field Summary

Fields

Modifier and Type	Field	Description
protected Queue<BasicPoolEntry>	freeConnections	The list of free connections
protected int	maxTotalConnections
protected ClientConnectionOperator	operator	Connection operator for this pool
protected Map<HttpRoute,RouteSpecificPool>	routeToPool	A map of route-specific pools.
protected Queue<WaitingThread>	waitingThreads	The list of WaitingThreads waiting for a connection

Fields inherited from class org.apache.http.impl.conn.tsccm.AbstractConnPool

idleConnHandler, isShutDown, issuedConnections, numConnections, poolLock, refQueue

Constructor Summary

Constructors

Constructor	Description
ConnPoolByRoute(ClientConnectionOperator operator, HttpParams params)	Creates a new connection pool, managed by route.

Method Summary

Modifier and Type	Method	Description
protected BasicPoolEntry	createEntry(RouteSpecificPool rospl, ClientConnectionOperator op)	Creates a new pool entry.
protected Queue<BasicPoolEntry>	createFreeConnQueue()	Creates the queue for freeConnections.
protected Map<HttpRoute,RouteSpecificPool>	createRouteToPoolMap()	Creates the map for routeToPool.
protected Queue<WaitingThread>	createWaitingThreadQueue()	Creates the queue for waitingThreads.
void	deleteClosedConnections()	Deletes all entries for closed connections.
protected void	deleteEntry(BasicPoolEntry entry)	Deletes a given pool entry.
protected void	deleteLeastUsedEntry()	Delete an old, free pool entry to make room for a new one.
void	freeEntry(BasicPoolEntry entry, boolean reusable, long validDuration, TimeUnit timeUnit)	Returns an entry into the pool.
int	getConnectionsInPool(HttpRoute route)
protected BasicPoolEntry	getEntryBlocking(HttpRoute route, Object state, long timeout, TimeUnit tunit, WaitingThreadAborter aborter)	Obtains a pool entry with a connection within the given timeout.
protected BasicPoolEntry	getFreeEntry(RouteSpecificPool rospl, Object state)	If available, get a free pool entry for a route.
protected RouteSpecificPool	getRoutePool(HttpRoute route, boolean create)	Get a route-specific pool of available connections.
protected void	handleLostEntry(HttpRoute route)	Handles cleaning up for a lost pool entry with the given route.
protected RouteSpecificPool	newRouteSpecificPool(HttpRoute route)	Creates a new route-specific pool.
protected WaitingThread	newWaitingThread(Condition cond, RouteSpecificPool rospl)	Creates a new waiting thread.
protected void	notifyWaitingThread(RouteSpecificPool rospl)	Notifies a waiting thread that a connection is available.
PoolEntryRequest	requestPoolEntry(HttpRoute route, Object state)	Returns a new PoolEntryRequest, from which a BasicPoolEntry can be obtained, or the request can be aborted.
void	shutdown()	Shuts down this pool and all associated resources.

Methods inherited from class org.apache.http.impl.conn.tsccm.AbstractConnPool

closeConnection, closeExpiredConnections, closeIdleConnections, enableConnectionGC, getEntry, handleReference

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

operator

protected final ClientConnectionOperator operator

Connection operator for this pool

freeConnections

protected Queue<BasicPoolEntry> freeConnections

The list of free connections

waitingThreads

protected Queue<WaitingThread> waitingThreads

The list of WaitingThreads waiting for a connection

routeToPool

protected final Map<HttpRoute,RouteSpecificPool> routeToPool

A map of route-specific pools. Keys are of class HttpRoute, values of class RouteSpecificPool.

maxTotalConnections

protected final int maxTotalConnections

Constructor Details

ConnPoolByRoute

public ConnPoolByRoute(ClientConnectionOperator operator, HttpParams params)

Creates a new connection pool, managed by route.

Method Details

createFreeConnQueue

protected Queue<BasicPoolEntry> createFreeConnQueue()

Creates the queue for freeConnections. Called once by the constructor.

Returns:

a queue

createWaitingThreadQueue

protected Queue<WaitingThread> createWaitingThreadQueue()

Creates the queue for waitingThreads. Called once by the constructor.

Returns:

a queue

createRouteToPoolMap

protected Map<HttpRoute,RouteSpecificPool> createRouteToPoolMap()

Creates the map for routeToPool. Called once by the constructor.

Returns:

a map

newRouteSpecificPool

protected RouteSpecificPool newRouteSpecificPool(HttpRoute route)

Creates a new route-specific pool. Called by getRoutePool(org.apache.http.conn.routing.HttpRoute, boolean) when necessary.

Parameters:

route - the route

Returns:

the new pool

newWaitingThread

protected WaitingThread newWaitingThread(Condition cond, RouteSpecificPool rospl)

Creates a new waiting thread. Called by getRoutePool(org.apache.http.conn.routing.HttpRoute, boolean) when necessary.

Parameters:

cond - the condition to wait for

rospl - the route specific pool, or null

Returns:

a waiting thread representation

getRoutePool

protected RouteSpecificPool getRoutePool(HttpRoute route, boolean create)

Get a route-specific pool of available connections.

Parameters:

route - the route

create - whether to create the pool if it doesn't exist

Returns:

the pool for the argument route, never null if create is true

getConnectionsInPool

public int getConnectionsInPool(HttpRoute route)

requestPoolEntry

public PoolEntryRequest requestPoolEntry(HttpRoute route, Object state)

Description copied from class: AbstractConnPool

Returns a new PoolEntryRequest, from which a BasicPoolEntry can be obtained, or the request can be aborted.

Specified by:

requestPoolEntry in class AbstractConnPool

getEntryBlocking

protected BasicPoolEntry getEntryBlocking(HttpRoute route, Object state, long timeout, TimeUnit tunit, WaitingThreadAborter aborter) throws ConnectionPoolTimeoutException, InterruptedException

Obtains a pool entry with a connection within the given timeout. If a WaitingThread is used to block, WaitingThreadAborter.setWaitingThread(WaitingThread) must be called before blocking, to allow the thread to be interrupted.

Parameters:

route - the route for which to get the connection

timeout - the timeout, 0 or negative for no timeout

tunit - the unit for the timeout, may be null only if there is no timeout

aborter - an object which can abort a WaitingThread.

Returns:

pool entry holding a connection for the route

Throws:

ConnectionPoolTimeoutException - if the timeout expired

InterruptedException - if the calling thread was interrupted

freeEntry

public void freeEntry(BasicPoolEntry entry, boolean reusable, long validDuration, TimeUnit timeUnit)

Description copied from class: AbstractConnPool

Returns an entry into the pool. The connection of the entry is expected to be in a suitable state, either open and re-usable, or closed. The pool will not make any attempt to determine whether it can be re-used or not.

Specified by:

freeEntry in class AbstractConnPool

Parameters:

entry - the entry for the connection to release

reusable - true if the entry is deemed reusable, false otherwise.

validDuration - The duration that the entry should remain free and reusable.

timeUnit - The unit of time the duration is measured in.

getFreeEntry

protected BasicPoolEntry getFreeEntry(RouteSpecificPool rospl, Object state)

If available, get a free pool entry for a route.

Parameters:

rospl - the route-specific pool from which to get an entry

Returns:

an available pool entry for the given route, or null if none is available

createEntry

protected BasicPoolEntry createEntry(RouteSpecificPool rospl, ClientConnectionOperator op)

Creates a new pool entry. This method assumes that the new connection will be handed out immediately.

Parameters:

rospl - the route-specific pool for which to create the entry

op - the operator for creating a connection

Returns:

the new pool entry for a new connection

deleteEntry

protected void deleteEntry(BasicPoolEntry 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.

Parameters:

entry - the pool entry for the connection to delete

deleteLeastUsedEntry

protected void deleteLeastUsedEntry()

Delete an old, free pool entry to make room for a new one. Used to replace pool entries with ones for a different route.

handleLostEntry

protected void handleLostEntry(HttpRoute route)

Description copied from class: AbstractConnPool

Handles cleaning up for a lost pool entry with the given route. A lost pool entry corresponds to a connection that was garbage collected instead of being properly released.

Specified by:

handleLostEntry in class AbstractConnPool

Parameters:

route - the route of the pool entry that was lost

notifyWaitingThread

protected void notifyWaitingThread(RouteSpecificPool rospl)

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.

Parameters:

rospl - the pool in which to notify, or null

deleteClosedConnections

public void deleteClosedConnections()

Description copied from class: AbstractConnPool

Deletes all entries for closed connections.

Specified by:

deleteClosedConnections in class AbstractConnPool

shutdown

public void shutdown()

Description copied from class: AbstractConnPool

Shuts down this pool and all associated resources. Overriding methods MUST call the implementation here!

Overrides:

shutdown in class AbstractConnPool