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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
* freeEntries;
/** The list of threads waiting for this pool. */
protected final Queue waitingThreads;
/** The number of created entries. */
protected int numEntries;
/**
* @deprecated (4.1) use {@link RouteSpecificPool#RouteSpecificPool(HttpRoute, ConnPerRoute)}
*/
@Deprecated
public RouteSpecificPool(final HttpRoute route, final int maxEntries) {
this.route = route;
this.maxEntries = maxEntries;
this.connPerRoute = new ConnPerRoute() {
@Override
public int getMaxForRoute(final HttpRoute unused) {
return RouteSpecificPool.this.maxEntries;
}
};
this.freeEntries = new LinkedList();
this.waitingThreads = new LinkedList();
this.numEntries = 0;
}
/**
* Creates a new route-specific pool.
*
* @param route the route for which to pool
* @param connPerRoute the connections per route configuration
*/
public RouteSpecificPool(final HttpRoute route, final ConnPerRoute connPerRoute) {
this.route = route;
this.connPerRoute = connPerRoute;
this.maxEntries = connPerRoute.getMaxForRoute(route);
this.freeEntries = new LinkedList();
this.waitingThreads = new LinkedList();
this.numEntries = 0;
}
/**
* Obtains the route for which this pool is specific.
*
* @return the route
*/
public final HttpRoute getRoute() {
return route;
}
/**
* Obtains the maximum number of entries allowed for this pool.
*
* @return the max entry number
*/
public final int getMaxEntries() {
return maxEntries;
}
/**
* Indicates whether this pool is unused.
* A pool is unused if there is neither an entry nor a waiting thread.
* All entries count, not only the free but also the allocated ones.
*
* @return {@code true} if this pool is unused,
* {@code false} otherwise
*/
public boolean isUnused() {
return (numEntries < 1) && waitingThreads.isEmpty();
}
/**
* Return remaining capacity of this pool
*
* @return capacity
*/
public int getCapacity() {
return connPerRoute.getMaxForRoute(route) - numEntries;
}
/**
* Obtains the number of entries.
* This includes not only the free entries, but also those that
* have been created and are currently issued to an application.
*
* @return the number of entries for the route of this pool
*/
public final int getEntryCount() {
return numEntries;
}
/**
* Obtains a free entry from this pool, if one is available.
*
* @return an available pool entry, or {@code null} if there is none
*/
public BasicPoolEntry allocEntry(final Object state) {
if (!freeEntries.isEmpty()) {
final ListIterator it = freeEntries.listIterator(freeEntries.size());
while (it.hasPrevious()) {
final BasicPoolEntry entry = it.previous();
if (entry.getState() == null || LangUtils.equals(state, entry.getState())) {
it.remove();
return entry;
}
}
}
if (getCapacity() == 0 && !freeEntries.isEmpty()) {
final BasicPoolEntry entry = freeEntries.remove();
entry.shutdownEntry();
final OperatedClientConnection conn = entry.getConnection();
try {
conn.close();
} catch (final IOException ex) {
log.debug("I/O error closing connection", ex);
}
return entry;
}
return null;
}
/**
* Returns an allocated entry to this pool.
*
* @param entry the entry obtained from {@link #allocEntry allocEntry}
* or presented to {@link #createdEntry createdEntry}
*/
public void freeEntry(final BasicPoolEntry entry) {
if (numEntries < 1) {
throw new IllegalStateException
("No entry created for this pool. " + route);
}
if (numEntries <= freeEntries.size()) {
throw new IllegalStateException
("No entry allocated from this pool. " + route);
}
freeEntries.add(entry);
}
/**
* Indicates creation of an entry for this pool.
* The entry will not be added to the list of free entries,
* it is only recognized as belonging to this pool now. It can then
* be passed to {@link #freeEntry freeEntry}.
*
* @param entry the entry that was created for this pool
*/
public void createdEntry(final BasicPoolEntry entry) {
Args.check(route.equals(entry.getPlannedRoute()), "Entry not planned for this pool");
numEntries++;
}
/**
* Deletes an entry from this pool.
* Only entries that are currently free in this pool can be deleted.
* Allocated entries can not be deleted.
*
* @param entry the entry to delete from this pool
*
* @return {@code true} if the entry was found and deleted, or
* {@code false} if the entry was not found
*/
public boolean deleteEntry(final BasicPoolEntry entry) {
final boolean found = freeEntries.remove(entry);
if (found) {
numEntries--;
}
return found;
}
/**
* Forgets about an entry from this pool.
* This method is used to indicate that an entry
* {@link #allocEntry allocated}
* from this pool has been lost and will not be returned.
*/
public void dropEntry() {
Asserts.check(numEntries > 0, "There is no entry that could be dropped");
numEntries--;
}
/**
* Adds a waiting thread.
* This pool makes no attempt to match waiting threads with pool entries.
* It is the caller's responsibility to check that there is no entry
* before adding a waiting thread.
*
* @param wt the waiting thread
*/
public void queueThread(final WaitingThread wt) {
Args.notNull(wt, "Waiting thread");
this.waitingThreads.add(wt);
}
/**
* Checks whether there is a waiting thread in this pool.
*
* @return {@code true} if there is a waiting thread,
* {@code false} otherwise
*/
public boolean hasThread() {
return !this.waitingThreads.isEmpty();
}
/**
* Returns the next thread in the queue.
*
* @return a waiting thread, or {@code null} if there is none
*/
public WaitingThread nextThread() {
return this.waitingThreads.peek();
}
/**
* Removes a waiting thread, if it is queued.
*
* @param wt the waiting thread
*/
public void removeThread(final WaitingThread wt) {
if (wt == null) {
return;
}
this.waitingThreads.remove(wt);
}
} // class RouteSpecificPool