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/*
* ====================================================================
* 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
*
* Please note that this class does not maintain its own pool of execution {@link Thread}s.
* Therefore, one must call {@link Future#get()} or {@link Future#get(long, TimeUnit)}
* method on the {@link Future} object returned by the
* {@link #lease(Object, Object, FutureCallback)} method in order for the lease operation
* to complete.
*
* @param the route type that represents the opposite endpoint of a pooled
* connection.
* @param the connection type.
* @param the type of the pool entry containing a pooled connection.
* @since 4.2
*/
@Contract(threading = ThreadingBehavior.SAFE_CONDITIONAL)
public abstract class AbstractConnPool>
implements ConnPool, ConnPoolControl {
private final Lock lock;
private final Condition condition;
private final ConnFactory connFactory;
private final Map> routeToPool;
private final Set leased;
private final LinkedList available;
private final LinkedList> pending;
private final Map maxPerRoute;
private volatile boolean isShutDown;
private volatile int defaultMaxPerRoute;
private volatile int maxTotal;
private volatile int validateAfterInactivity;
public AbstractConnPool(
final ConnFactory connFactory,
final int defaultMaxPerRoute,
final int maxTotal) {
super();
this.connFactory = Args.notNull(connFactory, "Connection factory");
this.defaultMaxPerRoute = Args.positive(defaultMaxPerRoute, "Max per route value");
this.maxTotal = Args.positive(maxTotal, "Max total value");
this.lock = new ReentrantLock();
this.condition = this.lock.newCondition();
this.routeToPool = new HashMap>();
this.leased = new HashSet();
this.available = new LinkedList();
this.pending = new LinkedList>();
this.maxPerRoute = new HashMap();
}
/**
* Creates a new entry for the given connection with the given route.
*/
protected abstract E createEntry(T route, C conn);
/**
* @since 4.3
*/
protected void onLease(final E entry) {
}
/**
* @since 4.3
*/
protected void onRelease(final E entry) {
}
/**
* @since 4.4
*/
protected void onReuse(final E entry) {
}
/**
* @since 4.4
*/
protected boolean validate(final E entry) {
return true;
}
public boolean isShutdown() {
return this.isShutDown;
}
/**
* Shuts down the pool.
*/
public void shutdown() throws IOException {
if (this.isShutDown) {
return ;
}
this.isShutDown = true;
this.lock.lock();
try {
for (final E entry: this.available) {
entry.close();
}
for (final E entry: this.leased) {
entry.close();
}
for (final RouteSpecificPool pool: this.routeToPool.values()) {
pool.shutdown();
}
this.routeToPool.clear();
this.leased.clear();
this.available.clear();
} finally {
this.lock.unlock();
}
}
private RouteSpecificPool getPool(final T route) {
RouteSpecificPool pool = this.routeToPool.get(route);
if (pool == null) {
pool = new RouteSpecificPool(route) {
@Override
protected E createEntry(final C conn) {
return AbstractConnPool.this.createEntry(route, conn);
}
};
this.routeToPool.put(route, pool);
}
return pool;
}
private static Exception operationAborted() {
return new CancellationException("Operation aborted");
}
/**
* {@inheritDoc}
*
* Please note that this class does not maintain its own pool of execution
* {@link Thread}s. Therefore, one must call {@link Future#get()}
* or {@link Future#get(long, TimeUnit)} method on the {@link Future}
* returned by this method in order for the lease operation to complete.
*/
@Override
public Future lease(final T route, final Object state, final FutureCallback callback) {
Args.notNull(route, "Route");
Asserts.check(!this.isShutDown, "Connection pool shut down");
return new Future() {
private final AtomicBoolean cancelled = new AtomicBoolean(false);
private final AtomicBoolean done = new AtomicBoolean(false);
private final AtomicReference entryRef = new AtomicReference(null);
@Override
public boolean cancel(final boolean mayInterruptIfRunning) {
if (done.compareAndSet(false, true)) {
cancelled.set(true);
lock.lock();
try {
condition.signalAll();
} finally {
lock.unlock();
}
if (callback != null) {
callback.cancelled();
}
return true;
}
return false;
}
@Override
public boolean isCancelled() {
return cancelled.get();
}
@Override
public boolean isDone() {
return done.get();
}
@Override
public E get() throws InterruptedException, ExecutionException {
try {
return get(0L, TimeUnit.MILLISECONDS);
} catch (final TimeoutException ex) {
throw new ExecutionException(ex);
}
}
@Override
public E get(final long timeout, final TimeUnit timeUnit) throws InterruptedException, ExecutionException, TimeoutException {
for (;;) {
synchronized (this) {
try {
final E entry = entryRef.get();
if (entry != null) {
return entry;
}
if (done.get()) {
throw new ExecutionException(operationAborted());
}
final E leasedEntry = getPoolEntryBlocking(route, state, timeout, timeUnit, this);
if (validateAfterInactivity > 0) {
if (leasedEntry.getUpdated() + validateAfterInactivity <= System.currentTimeMillis()) {
if (!validate(leasedEntry)) {
leasedEntry.close();
release(leasedEntry, false);
continue;
}
}
}
if (done.compareAndSet(false, true)) {
entryRef.set(leasedEntry);
done.set(true);
onLease(leasedEntry);
if (callback != null) {
callback.completed(leasedEntry);
}
return leasedEntry;
} else {
release(leasedEntry, true);
throw new ExecutionException(operationAborted());
}
} catch (final IOException ex) {
if (done.compareAndSet(false, true)) {
if (callback != null) {
callback.failed(ex);
}
}
throw new ExecutionException(ex);
}
}
}
}
};
}
/**
* Attempts to lease a connection for the given route and with the given
* state from the pool.
*
* Please note that this class does not maintain its own pool of execution
* {@link Thread}s. Therefore, one must call {@link Future#get()}
* or {@link Future#get(long, TimeUnit)} method on the {@link Future}
* returned by this method in order for the lease operation to complete.
*
* @param route route of the connection.
* @param state arbitrary object that represents a particular state
* (usually a security principal or a unique token identifying
* the user whose credentials have been used while establishing the connection).
* May be {@code null}.
* @return future for a leased pool entry.
*/
public Future lease(final T route, final Object state) {
return lease(route, state, null);
}
private E getPoolEntryBlocking(
final T route, final Object state,
final long timeout, final TimeUnit timeUnit,
final Future future) throws IOException, InterruptedException, ExecutionException, TimeoutException {
Date deadline = null;
if (timeout > 0) {
deadline = new Date (System.currentTimeMillis() + timeUnit.toMillis(timeout));
}
this.lock.lock();
try {
E entry;
for (;;) {
Asserts.check(!this.isShutDown, "Connection pool shut down");
if (future.isCancelled()) {
throw new ExecutionException(operationAborted());
}
final RouteSpecificPool pool = getPool(route);
for (;;) {
entry = pool.getFree(state);
if (entry == null) {
break;
}
if (entry.isExpired(System.currentTimeMillis())) {
entry.close();
}
if (entry.isClosed()) {
this.available.remove(entry);
pool.free(entry, false);
} else {
break;
}
}
if (entry != null) {
this.available.remove(entry);
this.leased.add(entry);
onReuse(entry);
return entry;
}
// New connection is needed
final int maxPerRoute = getMax(route);
// Shrink the pool prior to allocating a new connection
final int excess = Math.max(0, pool.getAllocatedCount() + 1 - maxPerRoute);
if (excess > 0) {
for (int i = 0; i < excess; i++) {
final E lastUsed = pool.getLastUsed();
if (lastUsed == null) {
break;
}
lastUsed.close();
this.available.remove(lastUsed);
pool.remove(lastUsed);
}
}
if (pool.getAllocatedCount() < maxPerRoute) {
final int totalUsed = this.leased.size();
final int freeCapacity = Math.max(this.maxTotal - totalUsed, 0);
if (freeCapacity > 0) {
final int totalAvailable = this.available.size();
if (totalAvailable > freeCapacity - 1) {
final E lastUsed = this.available.removeLast();
lastUsed.close();
final RouteSpecificPool otherpool = getPool(lastUsed.getRoute());
otherpool.remove(lastUsed);
}
final C conn = this.connFactory.create(route);
entry = pool.add(conn);
this.leased.add(entry);
return entry;
}
}
boolean success = false;
try {
pool.queue(future);
this.pending.add(future);
if (deadline != null) {
success = this.condition.awaitUntil(deadline);
} else {
this.condition.await();
success = true;
}
if (future.isCancelled()) {
throw new ExecutionException(operationAborted());
}
} 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.
pool.unqueue(future);
this.pending.remove(future);
}
// check for spurious wakeup vs. timeout
if (!success && (deadline != null && deadline.getTime() <= System.currentTimeMillis())) {
break;
}
}
throw new TimeoutException("Timeout waiting for connection");
} finally {
this.lock.unlock();
}
}
@Override
public void release(final E entry, final boolean reusable) {
this.lock.lock();
try {
if (this.leased.remove(entry)) {
final RouteSpecificPool pool = getPool(entry.getRoute());
pool.free(entry, reusable);
if (reusable && !this.isShutDown) {
this.available.addFirst(entry);
} else {
entry.close();
}
onRelease(entry);
Future future = pool.nextPending();
if (future != null) {
this.pending.remove(future);
} else {
future = this.pending.poll();
}
if (future != null) {
this.condition.signalAll();
}
}
} finally {
this.lock.unlock();
}
}
private int getMax(final T route) {
final Integer v = this.maxPerRoute.get(route);
return v != null ? v.intValue() : this.defaultMaxPerRoute;
}
@Override
public void setMaxTotal(final int max) {
Args.positive(max, "Max value");
this.lock.lock();
try {
this.maxTotal = max;
} finally {
this.lock.unlock();
}
}
@Override
public int getMaxTotal() {
this.lock.lock();
try {
return this.maxTotal;
} finally {
this.lock.unlock();
}
}
@Override
public void setDefaultMaxPerRoute(final int max) {
Args.positive(max, "Max per route value");
this.lock.lock();
try {
this.defaultMaxPerRoute = max;
} finally {
this.lock.unlock();
}
}
@Override
public int getDefaultMaxPerRoute() {
this.lock.lock();
try {
return this.defaultMaxPerRoute;
} finally {
this.lock.unlock();
}
}
@Override
public void setMaxPerRoute(final T route, final int max) {
Args.notNull(route, "Route");
this.lock.lock();
try {
if (max > -1) {
this.maxPerRoute.put(route, Integer.valueOf(max));
} else {
this.maxPerRoute.remove(route);
}
} finally {
this.lock.unlock();
}
}
@Override
public int getMaxPerRoute(final T route) {
Args.notNull(route, "Route");
this.lock.lock();
try {
return getMax(route);
} finally {
this.lock.unlock();
}
}
@Override
public PoolStats getTotalStats() {
this.lock.lock();
try {
return new PoolStats(
this.leased.size(),
this.pending.size(),
this.available.size(),
this.maxTotal);
} finally {
this.lock.unlock();
}
}
@Override
public PoolStats getStats(final T route) {
Args.notNull(route, "Route");
this.lock.lock();
try {
final RouteSpecificPool pool = getPool(route);
return new PoolStats(
pool.getLeasedCount(),
pool.getPendingCount(),
pool.getAvailableCount(),
getMax(route));
} finally {
this.lock.unlock();
}
}
/**
* Returns snapshot of all knows routes
* @return the set of routes
*
* @since 4.4
*/
public Set getRoutes() {
this.lock.lock();
try {
return new HashSet(routeToPool.keySet());
} finally {
this.lock.unlock();
}
}
/**
* Enumerates all available connections.
*
* @since 4.3
*/
protected void enumAvailable(final PoolEntryCallback callback) {
this.lock.lock();
try {
final Iterator it = this.available.iterator();
while (it.hasNext()) {
final E entry = it.next();
callback.process(entry);
if (entry.isClosed()) {
final RouteSpecificPool pool = getPool(entry.getRoute());
pool.remove(entry);
it.remove();
}
}
purgePoolMap();
} finally {
this.lock.unlock();
}
}
/**
* Enumerates all leased connections.
*
* @since 4.3
*/
protected void enumLeased(final PoolEntryCallback callback) {
this.lock.lock();
try {
final Iterator it = this.leased.iterator();
while (it.hasNext()) {
final E entry = it.next();
callback.process(entry);
}
} finally {
this.lock.unlock();
}
}
private void purgePoolMap() {
final Iterator>> it = this.routeToPool.entrySet().iterator();
while (it.hasNext()) {
final Map.Entry> entry = it.next();
final RouteSpecificPool pool = entry.getValue();
if (pool.getPendingCount() + pool.getAllocatedCount() == 0) {
it.remove();
}
}
}
/**
* Closes connections that have been idle longer than the given period
* of time and evicts them from the pool.
*
* @param idletime maximum idle time.
* @param timeUnit time unit.
*/
public void closeIdle(final long idletime, final TimeUnit timeUnit) {
Args.notNull(timeUnit, "Time unit");
long time = timeUnit.toMillis(idletime);
if (time < 0) {
time = 0;
}
final long deadline = System.currentTimeMillis() - time;
enumAvailable(new PoolEntryCallback() {
@Override
public void process(final PoolEntry entry) {
if (entry.getUpdated() <= deadline) {
entry.close();
}
}
});
}
/**
* Closes expired connections and evicts them from the pool.
*/
public void closeExpired() {
final long now = System.currentTimeMillis();
enumAvailable(new PoolEntryCallback() {
@Override
public void process(final PoolEntry entry) {
if (entry.isExpired(now)) {
entry.close();
}
}
});
}
/**
* @return the number of milliseconds
* @since 4.4
*/
public int getValidateAfterInactivity() {
return this.validateAfterInactivity;
}
/**
* @param ms the number of milliseconds
* @since 4.4
*/
public void setValidateAfterInactivity(final int ms) {
this.validateAfterInactivity = ms;
}
@Override
public String toString() {
this.lock.lock();
try {
final StringBuilder buffer = new StringBuilder();
buffer.append("[leased: ");
buffer.append(this.leased);
buffer.append("][available: ");
buffer.append(this.available);
buffer.append("][pending: ");
buffer.append(this.pending);
buffer.append("]");
return buffer.toString();
} finally {
this.lock.unlock();
}
}
}