Java tutorial
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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.ExecutionException; import java.util.concurrent.Future; import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeoutException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.annotation.ThreadSafe; import org.apache.http.conn.ClientConnectionManager; import org.apache.http.conn.ClientConnectionOperator; import org.apache.http.conn.ClientConnectionRequest; import org.apache.http.conn.ConnectionPoolTimeoutException; import org.apache.http.conn.DnsResolver; import org.apache.http.conn.ManagedClientConnection; import org.apache.http.conn.OperatedClientConnection; import org.apache.http.conn.routing.HttpRoute; import org.apache.http.conn.scheme.SchemeRegistry; import org.apache.http.pool.ConnPoolControl; import org.apache.http.pool.PoolStats; /** * Manages a pool of {@link OperatedClientConnection client connections} and * is able to service connection requests from multiple execution threads. * Connections are pooled on a per route basis. A request for a route which * already the manager has persistent connections for available in the pool * will be services by leasing a connection from the pool rather than * creating a brand new connection. * <p> * PoolingConnectionManager maintains a maximum limit of connection on * a per route basis and in total. Per default this implementation will * create no more than than 2 concurrent connections per given route * and no more 20 connections in total. For many real-world applications * these limits may prove too constraining, especially if they use HTTP * as a transport protocol for their services. Connection limits, however, * can be adjusted using HTTP parameters. * * @since 4.2 */ @ThreadSafe public class FixedPoolingClientConnectionManager implements ClientConnectionManager, ConnPoolControl<HttpRoute> { private final Log log = LogFactory.getLog(getClass()); private final SchemeRegistry schemeRegistry; private final FixedHttpConnPool pool; private final ClientConnectionOperator operator; /** the custom-configured DNS lookup mechanism. */ private final DnsResolver dnsResolver; public FixedPoolingClientConnectionManager(final SchemeRegistry schreg) { this(schreg, -1, TimeUnit.MILLISECONDS); } public FixedPoolingClientConnectionManager(final SchemeRegistry schreg, final DnsResolver dnsResolver) { this(schreg, -1, TimeUnit.MILLISECONDS, dnsResolver); } public FixedPoolingClientConnectionManager() { this(SchemeRegistryFactory.createDefault()); } public FixedPoolingClientConnectionManager(final SchemeRegistry schemeRegistry, final long timeToLive, final TimeUnit tunit) { this(schemeRegistry, timeToLive, tunit, new SystemDefaultDnsResolver()); } public FixedPoolingClientConnectionManager(final SchemeRegistry schemeRegistry, final long timeToLive, final TimeUnit tunit, final DnsResolver dnsResolver) { super(); if (schemeRegistry == null) { throw new IllegalArgumentException("Scheme registry may not be null"); } if (dnsResolver == null) { throw new IllegalArgumentException("DNS resolver may not be null"); } this.schemeRegistry = schemeRegistry; this.dnsResolver = dnsResolver; this.operator = createConnectionOperator(schemeRegistry); this.pool = new FixedHttpConnPool(this.log, 2, 20, timeToLive, tunit); } @Override protected void finalize() throws Throwable { try { shutdown(); } finally { super.finalize(); } } /** * 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. * * @return the connection operator to use */ protected ClientConnectionOperator createConnectionOperator(SchemeRegistry schreg) { return new DefaultClientConnectionOperator(schreg, this.dnsResolver); } public SchemeRegistry getSchemeRegistry() { return this.schemeRegistry; } private String format(final HttpRoute route, final Object state) { StringBuilder buf = new StringBuilder(); buf.append("[route: ").append(route).append("]"); if (state != null) { buf.append("[state: ").append(state).append("]"); } return buf.toString(); } private String formatStats(final HttpRoute route) { StringBuilder buf = new StringBuilder(); PoolStats totals = this.pool.getTotalStats(); PoolStats stats = this.pool.getStats(route); buf.append("[total kept alive: ").append(totals.getAvailable()).append("; "); buf.append("route allocated: ").append(stats.getLeased() + stats.getAvailable()); buf.append(" of ").append(stats.getMax()).append("; "); buf.append("total allocated: ").append(totals.getLeased() + totals.getAvailable()); buf.append(" of ").append(totals.getMax()).append("]"); return buf.toString(); } private String format(final HttpPoolEntry entry) { StringBuilder buf = new StringBuilder(); buf.append("[id: ").append(entry.getId()).append("]"); buf.append("[route: ").append(entry.getRoute()).append("]"); Object state = entry.getState(); if (state != null) { buf.append("[state: ").append(state).append("]"); } return buf.toString(); } public ClientConnectionRequest requestConnection(final HttpRoute route, final Object state) { if (route == null) { throw new IllegalArgumentException("HTTP route may not be null"); } if (this.log.isDebugEnabled()) { this.log.debug("Connection request: " + format(route, state) + formatStats(route)); } final Future<HttpPoolEntry> future = this.pool.lease(route, state); return new ClientConnectionRequest() { public void abortRequest() { future.cancel(true); } public ManagedClientConnection getConnection(final long timeout, final TimeUnit tunit) throws InterruptedException, ConnectionPoolTimeoutException { return leaseConnection(future, timeout, tunit); } }; } ManagedClientConnection leaseConnection(final Future<HttpPoolEntry> future, final long timeout, final TimeUnit tunit) throws InterruptedException, ConnectionPoolTimeoutException { HttpPoolEntry entry; try { entry = future.get(timeout, tunit); if (entry == null || future.isCancelled()) { throw new InterruptedException(); } if (entry.getConnection() == null) { throw new IllegalStateException("Pool entry with no connection"); } if (this.log.isDebugEnabled()) { this.log.debug("Connection leased: " + format(entry) + formatStats(entry.getRoute())); } return new ManagedClientConnectionImpl(this, this.operator, entry); } catch (ExecutionException ex) { Throwable cause = ex.getCause(); if (cause == null) { cause = ex; } this.log.error("Unexpected exception leasing connection from pool", cause); // Should never happen throw new InterruptedException(); } catch (TimeoutException ex) { throw new ConnectionPoolTimeoutException("Timeout waiting for connection"); } } public void releaseConnection(final ManagedClientConnection conn, final long keepalive, final TimeUnit tunit) { if (!(conn instanceof ManagedClientConnectionImpl)) { throw new IllegalArgumentException( "Connection class mismatch, " + "connection not obtained from this manager."); } ManagedClientConnectionImpl managedConn = (ManagedClientConnectionImpl) conn; if (managedConn.getManager() != this) { throw new IllegalStateException("Connection not obtained from this manager."); } synchronized (managedConn) { HttpPoolEntry entry = managedConn.detach(); if (entry == null) { return; } try { if (managedConn.isOpen() && !managedConn.isMarkedReusable()) { try { managedConn.shutdown(); } catch (IOException iox) { if (this.log.isDebugEnabled()) { this.log.debug("I/O exception shutting down released connection", iox); } } } entry.updateExpiry(keepalive, tunit != null ? tunit : TimeUnit.MILLISECONDS); if (this.log.isDebugEnabled()) { String s; if (keepalive > 0) { s = "for " + keepalive + " " + tunit; } else { s = "indefinitely"; } this.log.debug("Connection " + format(entry) + " can be kept alive " + s); } } finally { this.pool.release(entry, managedConn.isMarkedReusable()); } if (this.log.isDebugEnabled()) { this.log.debug("Connection released: " + format(entry) + formatStats(entry.getRoute())); } } } public void shutdown() { this.log.debug("Connection manager is shutting down"); try { this.pool.shutdown(); } catch (IOException ex) { this.log.debug("I/O exception shutting down connection manager", ex); } this.log.debug("Connection manager shut down"); } public void closeIdleConnections(long idleTimeout, TimeUnit tunit) { if (this.log.isDebugEnabled()) { this.log.debug("Closing connections idle longer than " + idleTimeout + " " + tunit); } this.pool.closeIdle(idleTimeout, tunit); } public void closeExpiredConnections() { this.log.debug("Closing expired connections"); this.pool.closeExpired(); } public int getMaxTotal() { return this.pool.getMaxTotal(); } public void setMaxTotal(int max) { this.pool.setMaxTotal(max); } public int getDefaultMaxPerRoute() { return this.pool.getDefaultMaxPerRoute(); } public void setDefaultMaxPerRoute(int max) { this.pool.setDefaultMaxPerRoute(max); } public int getMaxPerRoute(final HttpRoute route) { return this.pool.getMaxPerRoute(route); } public void setMaxPerRoute(final HttpRoute route, int max) { this.pool.setMaxPerRoute(route, max); } public PoolStats getTotalStats() { return this.pool.getTotalStats(); } public PoolStats getStats(final HttpRoute route) { return this.pool.getStats(route); } }