From dff91540f376f621a8fc1f640ad8e6b89c23df70 Mon Sep 17 00:00:00 2001
From: Roland Weber <rolandw@apache.org>
Date: Sun, 21 Jan 2007 13:28:45 +0000
Subject: [PATCH] connection manager, part 2 - example and a fix

git-svn-id: https://svn.apache.org/repos/asf/jakarta/httpcomponents/httpclient/trunk@498312 13f79535-47bb-0310-9956-ffa450edef68
---
 .../examples/conn/ManagerConnectDirect.java   | 210 ++++++++++++++++++
 .../impl/ThreadSafeClientConnManager.java     |  54 +++--
 2 files changed, 245 insertions(+), 19 deletions(-)
 create mode 100644 src/examples/org/apache/http/examples/conn/ManagerConnectDirect.java

diff --git a/src/examples/org/apache/http/examples/conn/ManagerConnectDirect.java b/src/examples/org/apache/http/examples/conn/ManagerConnectDirect.java
new file mode 100644
index 000000000..6b8ac5996
--- /dev/null
+++ b/src/examples/org/apache/http/examples/conn/ManagerConnectDirect.java
@@ -0,0 +1,210 @@
+/*
+ * $HeadURL$
+ * $Revision$
+ * $Date$
+ *
+ * ====================================================================
+ * 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
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.http.examples.conn;
+
+
+import org.apache.http.HttpHost;
+import org.apache.http.Header;
+import org.apache.http.HttpRequest;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpVersion;
+import org.apache.http.message.BasicHttpRequest;
+import org.apache.http.params.HttpParams;
+import org.apache.http.params.HttpProtocolParams;
+import org.apache.http.impl.DefaultHttpParams;
+import org.apache.http.protocol.HttpContext;
+import org.apache.http.protocol.HttpExecutionContext;
+
+import org.apache.http.conn.Scheme;
+import org.apache.http.conn.SocketFactory;
+import org.apache.http.conn.PlainSocketFactory;
+import org.apache.http.conn.HostConfiguration;
+import org.apache.http.conn.ManagedClientConnection;
+import org.apache.http.conn.ClientConnectionManager;
+import org.apache.http.conn.impl.ThreadSafeClientConnManager;
+
+
+
+/**
+ * How to open a direct connection using
+ * {@link ClientConnectionManager ClientConnectionManager}.
+ * This exemplifies the <i>opening</i> of the connection only.
+ * The subsequent message exchange in this example should not
+ * be used as a template.
+ *
+ * @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
+ *
+ *
+ * <!-- empty lines above to avoid 'svn diff' context problems -->
+ * @version $Revision$ $Date$
+ *
+ * @since 4.0
+ */
+public class ManagerConnectDirect {
+
+    /**
+     * The default parameters.
+     * Instantiated in {@link #setup setup}.
+     */
+    private static HttpParams defaultParameters = null;
+
+
+    /**
+     * Main entry point to this example.
+     *
+     * @param args      ignored
+     */
+    public final static void main(String[] args)
+        throws Exception {
+
+        final HttpHost target = new HttpHost("jakarta.apache.org", 80, "http");
+
+        setup(); // some general setup
+
+        // one operator can be used for many connections
+        ClientConnectionManager clcm = createManager();
+
+        HttpRequest req = createRequest(target);
+        HttpContext ctx = createContext();
+
+        System.out.println("preparing route to " + target);
+        HostConfiguration route = new HostConfiguration(target, null, null);
+
+        System.out.println("requesting connection for " + route);
+        ManagedClientConnection conn = clcm.getConnection(route);
+        try {
+            System.out.println("opening connection");
+            conn.open(route, ctx, getParams());
+
+            System.out.println("sending request");
+            conn.sendRequestHeader(req);
+            // there is no request entity
+            conn.flush();
+
+            System.out.println("receiving response header");
+            HttpResponse rsp = conn.receiveResponseHeader(getParams());
+
+            System.out.println("----------------------------------------");
+            System.out.println(rsp.getStatusLine());
+            Header[] headers = rsp.getAllHeaders();
+            for (int i=0; i<headers.length; i++) {
+                System.out.println(headers[i]);
+            }
+            System.out.println("----------------------------------------");
+
+            System.out.println("closing connection");
+            conn.close();
+
+        } finally {
+
+            if (conn.isOpen()) {
+                System.out.println("shutting down connection");
+                try {
+                    conn.shutdown();
+                } catch (Exception x) {
+                    System.out.println("problem during shutdown");
+                    x.printStackTrace(System.out);
+                }
+            }
+
+            System.out.println("releasing connection");
+            clcm.releaseConnection(conn);
+        }
+
+    } // main
+
+
+    private final static ClientConnectionManager createManager() {
+        return new ThreadSafeClientConnManager(getParams());
+    }
+
+
+    /**
+     * Performs general setup.
+     * This should be called only once.
+     */
+    private final static void setup() {
+
+        // Register the "http" protocol scheme, it is required
+        // by the default operator to look up socket factories.
+        SocketFactory sf = PlainSocketFactory.getSocketFactory();
+        Scheme.registerScheme("http", new Scheme("http", sf, 80));
+
+        // Prepare parameters.
+        // Since this example doesn't use the full core framework,
+        // only few parameters are actually required.
+        HttpParams params = new DefaultHttpParams();
+        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
+        HttpProtocolParams.setUseExpectContinue(params, false);
+        defaultParameters = params;
+
+    } // setup
+
+
+    private final static HttpParams getParams() {
+        return defaultParameters;
+    }
+
+
+    /**
+     * Creates a request to execute in this example.
+     * In a real application, request interceptors should be used
+     * to add the required headers.
+     *
+     * @param target    the target server for the request
+     *
+     * @return  a request without an entity
+     */
+    private final static HttpRequest createRequest(HttpHost target) {
+
+        HttpRequest req = new BasicHttpRequest
+            ("OPTIONS", "*", HttpVersion.HTTP_1_1);
+
+        req.addHeader("Host", target.getHostName());
+
+        return req;
+    }
+
+
+    /**
+     * Creates a context for executing a request.
+     * Since this example doesn't really use the execution framework,
+     * the context can be left empty.
+     *
+     * @return  a new, empty context
+     */
+    private final static HttpContext createContext() {
+        return new HttpExecutionContext(null);
+    }
+
+} // class ManagerConnectDirect
+
diff --git a/src/java/org/apache/http/conn/impl/ThreadSafeClientConnManager.java b/src/java/org/apache/http/conn/impl/ThreadSafeClientConnManager.java
index de6b86d13..3edaf58e4 100644
--- a/src/java/org/apache/http/conn/impl/ThreadSafeClientConnManager.java
+++ b/src/java/org/apache/http/conn/impl/ThreadSafeClientConnManager.java
@@ -293,6 +293,8 @@ public class ThreadSafeClientConnManager
                 }
             }
         }
+
+
         return entry;
 
     } // doGetConnection
@@ -506,7 +508,7 @@ public class ThreadSafeClientConnManager
                     (ConnectionSource) REFERENCE_TO_CONNECTION_SOURCE.get(ref);
                 if (source.connectionPool == connectionPool) {
                     referenceIter.remove();
-                    Object entry = ref.get(); // class TrackingPoolEntry
+                    Object entry = ref.get(); // TrackingPoolEntry
                     if (entry != null) {
                         connectionsToClose.add(entry);
                     }
@@ -679,8 +681,11 @@ public class ThreadSafeClientConnManager
             idleConnectionHandler.removeAll();
         }
 
+
         /**
          * Creates a new pool entry for an operated connection.
+         * This method assumes that the new connection will be handed
+         * out immediately.
          *
          * @param route   the route associated with the new entry
          * @param conn    the underlying connection for the new entry
@@ -696,6 +701,7 @@ public class ThreadSafeClientConnManager
                 LOG.debug("Allocating new connection, hostConfiguration=" + route);
             }
             TrackingPoolEntry entry = new TrackingPoolEntry(conn);
+            entry.plannedRoute = route;
             numConnections++;
             hostPool.numConnections++;
     
@@ -707,12 +713,15 @@ public class ThreadSafeClientConnManager
 
 
         /**
-         * Handles cleaning up for a lost connection with the given config.  Decrements any 
-         * connection counts and notifies waiting threads, if appropriate.
+         * Handles cleaning up for a lost connection with the given config.
+         * Decrements any connection counts and notifies waiting threads,
+         * if appropriate.
          * 
          * @param config the host configuration of the connection that was lost
          */
-        public synchronized void handleLostConnection(HostConfiguration config) {
+        public synchronized
+            void handleLostConnection(HostConfiguration config) {
+
             HostConnectionPool hostPool = getHostPool(config);
             hostPool.numConnections--;
             if (hostPool.numConnections < 1)
@@ -723,26 +732,28 @@ public class ThreadSafeClientConnManager
         }
 
         /**
-         * Get the pool (list) of connections available for the given hostConfig.
+         * Get the pool (list) of connections available for the given route.
          *
-         * @param hostConfiguration the configuraton for the connection pool
-         * @return a pool (list) of connections available for the given config
+         * @param route   the configuraton for the connection pool
+         * @return a pool (list) of connections available for the given route
          */
-        public synchronized HostConnectionPool getHostPool(HostConfiguration hostConfiguration) {
+        public synchronized
+            HostConnectionPool getHostPool(HostConfiguration route) {
 
             // Look for a list of connections for the given config
-            HostConnectionPool listConnections = (HostConnectionPool) 
-                mapHosts.get(hostConfiguration);
+            HostConnectionPool listConnections =
+                (HostConnectionPool) mapHosts.get(route);
             if (listConnections == null) {
                 // First time for this config
                 listConnections = new HostConnectionPool();
-                listConnections.hostConfiguration = hostConfiguration;
-                mapHosts.put(hostConfiguration, listConnections);
+                listConnections.hostConfiguration = route;
+                mapHosts.put(route, listConnections);
             }
-            
+
             return listConnections;
         }
 
+
         /**
          * If available, get a free connection for this host
          *
@@ -900,7 +911,7 @@ public class ThreadSafeClientConnManager
          */
         private void freeConnection(TrackingPoolEntry entry) {
 
-            HostConfiguration route = entry.route;
+            HostConfiguration route = entry.plannedRoute;
 
             if (LOG.isDebugEnabled()) {
                 LOG.debug("Freeing connection, hostConfig=" + route);
@@ -917,7 +928,8 @@ public class ThreadSafeClientConnManager
                 
                 HostConnectionPool hostPool = getHostPool(route);
 
-                // Put the connect back in the available list and notify a waiter
+                // Put the connection back in the available list
+                // and notify a waiter
                 hostPool.freeConnections.add(entry);
                 if (hostPool.numConnections == 0) {
                     // for some reason this connection pool didn't already exist
@@ -927,8 +939,9 @@ public class ThreadSafeClientConnManager
                 }
 
                 freeConnections.add(entry);
-                // we can remove the reference to this connection as we have control over
-                // it again.  this also ensures that the connection manager can be GCed
+                // We can remove the reference to this connection as we have
+                // control over it again. This also ensures that the connection
+                // manager can be GCed.
                 removeReferenceToConnection(entry);
                 if (numConnections == 0) {
                     // for some reason this connection pool didn't already exist
@@ -1075,10 +1088,13 @@ public class ThreadSafeClientConnManager
         /** The underlying connection being pooled or used. */
         private OperatedClientConnection connection;
 
-        /** The host configuration part of the route. */
+        /** The route for which this entry gets allocated. */
+        private HostConfiguration plannedRoute;
+
+        /** The host configuration part of the tracked route. */
         private HostConfiguration route;
 
-        /** The tunnel created flag part of the route. */
+        /** The tunnel created flag part of the tracked route. */
         private boolean tunnelled;
 
         /** The connection manager. */