Java tutorial
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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.http2.impl.conn; import java.io.IOException; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicLong; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http2.HttpClientConnection; import org.apache.http2.annotation.GuardedBy; import org.apache.http2.annotation.ThreadSafe; import org.apache.http2.conn.ClientConnectionManager; import org.apache.http2.conn.ClientConnectionOperator; import org.apache.http2.conn.ClientConnectionRequest; import org.apache.http2.conn.ManagedClientConnection; import org.apache.http2.conn.OperatedClientConnection; import org.apache.http2.conn.routing.HttpRoute; import org.apache.http2.conn.scheme.SchemeRegistry; /** * A connection manager for a single connection. This connection manager maintains only one active * connection at a time. Even though this class is thread-safe it ought to be used by one execution * thread only. * <p/> * BasicClientConnManager will make an effort to reuse the connection for subsequent requests * with the same {@link HttpRoute route}. It will, however, close the existing connection and * open it for the given route, if the route of the persistent connection does not match that * of the connection request. If the connection has been already been allocated * {@link IllegalStateException} is thrown. * <p/> * This connection manager implementation can be used inside a EJB container instead of * {@link PoolingClientConnectionManager}. * * @since 4.2 */ @ThreadSafe public class BasicClientConnectionManager implements ClientConnectionManager { private final Log log = LogFactory.getLog(getClass()); private static final AtomicLong COUNTER = new AtomicLong(); /** The message to be logged on multiple allocation. */ public final static String MISUSE_MESSAGE = "Invalid use of BasicClientConnManager: connection still allocated.\n" + "Make sure to release the connection before allocating another one."; /** The schemes supported by this connection manager. */ private final SchemeRegistry schemeRegistry; /** The operator for opening and updating connections. */ private final ClientConnectionOperator connOperator; /** The one and only entry in this pool. */ @GuardedBy("this") private HttpPoolEntry poolEntry; /** The currently issued managed connection, if any. */ @GuardedBy("this") private ManagedClientConnectionImpl conn; /** Indicates whether this connection manager is shut down. */ @GuardedBy("this") private volatile boolean shutdown; /** * Creates a new simple connection manager. * * @param schreg the scheme registry */ public BasicClientConnectionManager(final SchemeRegistry schreg) { if (schreg == null) { throw new IllegalArgumentException("Scheme registry may not be null"); } this.schemeRegistry = schreg; this.connOperator = createConnectionOperator(schreg); } public BasicClientConnectionManager() { this(SchemeRegistryFactory.createDefault()); } @Override protected void finalize() throws Throwable { try { shutdown(); } finally { // Make sure we call overridden method even if shutdown barfs super.finalize(); } } public SchemeRegistry getSchemeRegistry() { return this.schemeRegistry; } protected ClientConnectionOperator createConnectionOperator(final SchemeRegistry schreg) { return new DefaultClientConnectionOperator(schreg); } public final ClientConnectionRequest requestConnection(final HttpRoute route, final Object state) { return new ClientConnectionRequest() { public void abortRequest() { // Nothing to abort, since requests are immediate. } public ManagedClientConnection getConnection(long timeout, TimeUnit tunit) { return BasicClientConnectionManager.this.getConnection(route, state); } }; } private void assertNotShutdown() { if (this.shutdown) { throw new IllegalStateException("Connection manager has been shut down"); } } ManagedClientConnection getConnection(final HttpRoute route, final Object state) { if (route == null) { throw new IllegalArgumentException("Route may not be null."); } synchronized (this) { assertNotShutdown(); if (this.log.isDebugEnabled()) { this.log.debug("Get connection for route " + route); } if (this.conn != null) { throw new IllegalStateException(MISUSE_MESSAGE); } if (this.poolEntry != null && !this.poolEntry.getPlannedRoute().equals(route)) { this.poolEntry.close(); this.poolEntry = null; } if (this.poolEntry == null) { String id = Long.toString(COUNTER.getAndIncrement()); OperatedClientConnection conn = this.connOperator.createConnection(); this.poolEntry = new HttpPoolEntry(this.log, id, route, conn, 0, TimeUnit.MILLISECONDS); } long now = System.currentTimeMillis(); if (this.poolEntry.isExpired(now)) { this.poolEntry.close(); this.poolEntry.getTracker().reset(); } this.conn = new ManagedClientConnectionImpl(this, this.connOperator, this.poolEntry); return this.conn; } } private void shutdownConnection(final HttpClientConnection conn) { try { conn.shutdown(); } catch (IOException iox) { if (this.log.isDebugEnabled()) { this.log.debug("I/O exception shutting down connection", iox); } } } public void releaseConnection(final ManagedClientConnection conn, long keepalive, TimeUnit tunit) { if (!(conn instanceof ManagedClientConnectionImpl)) { throw new IllegalArgumentException( "Connection class mismatch, " + "connection not obtained from this manager"); } ManagedClientConnectionImpl managedConn = (ManagedClientConnectionImpl) conn; synchronized (managedConn) { if (this.log.isDebugEnabled()) { this.log.debug("Releasing connection " + conn); } if (managedConn.getPoolEntry() == null) { return; // already released } ClientConnectionManager manager = managedConn.getManager(); if (manager != null && manager != this) { throw new IllegalStateException("Connection not obtained from this manager"); } synchronized (this) { if (this.shutdown) { shutdownConnection(managedConn); return; } try { if (managedConn.isOpen() && !managedConn.isMarkedReusable()) { shutdownConnection(managedConn); } this.poolEntry.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 can be kept alive " + s); } } finally { managedConn.detach(); this.conn = null; if (this.poolEntry.isClosed()) { this.poolEntry = null; } } } } } public void closeExpiredConnections() { synchronized (this) { assertNotShutdown(); long now = System.currentTimeMillis(); if (this.poolEntry != null && this.poolEntry.isExpired(now)) { this.poolEntry.close(); this.poolEntry.getTracker().reset(); } } } public void closeIdleConnections(long idletime, TimeUnit tunit) { if (tunit == null) { throw new IllegalArgumentException("Time unit must not be null."); } synchronized (this) { assertNotShutdown(); long time = tunit.toMillis(idletime); if (time < 0) { time = 0; } long deadline = System.currentTimeMillis() - time; if (this.poolEntry != null && this.poolEntry.getUpdated() <= deadline) { this.poolEntry.close(); this.poolEntry.getTracker().reset(); } } } public void shutdown() { synchronized (this) { this.shutdown = true; try { if (this.poolEntry != null) { this.poolEntry.close(); } } finally { this.poolEntry = null; this.conn = null; } } } }