//
   //  ========================================================================
   //  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.client;
  
  import java.io.IOException;
  import java.net.CookieManager;
  import java.net.CookiePolicy;
  import java.net.CookieStore;
  import java.net.SocketAddress;
  import java.net.URI;
  import java.nio.channels.SocketChannel;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Executor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  import org.eclipse.jetty.client.api.AuthenticationStore;
  import org.eclipse.jetty.client.api.Connection;
  import org.eclipse.jetty.client.api.ContentResponse;
  import org.eclipse.jetty.client.api.Destination;
  import org.eclipse.jetty.client.api.Request;
  import org.eclipse.jetty.client.api.Response;
  import org.eclipse.jetty.client.http.HttpClientTransportOverHTTP;
  import org.eclipse.jetty.http.HttpField;
  import org.eclipse.jetty.http.HttpHeader;
  import org.eclipse.jetty.http.HttpMethod;
  import org.eclipse.jetty.http.HttpScheme;
  import org.eclipse.jetty.io.ByteBufferPool;
  import org.eclipse.jetty.io.MappedByteBufferPool;
  import org.eclipse.jetty.util.Jetty;
  import org.eclipse.jetty.util.Promise;
  import org.eclipse.jetty.util.SocketAddressResolver;
  import org.eclipse.jetty.util.component.ContainerLifeCycle;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.eclipse.jetty.util.ssl.SslContextFactory;
  import org.eclipse.jetty.util.thread.QueuedThreadPool;
  import org.eclipse.jetty.util.thread.ScheduledExecutorScheduler;
  import org.eclipse.jetty.util.thread.Scheduler;
  
  /**
   * <p>{@link HttpClient} provides an efficient, asynchronous, non-blocking implementation
   * to perform HTTP requests to a server through a simple API that offers also blocking semantic.</p>
   * <p>{@link HttpClient} provides easy-to-use methods such as {@link #GET(String)} that allow to perform HTTP
   * requests in a one-liner, but also gives the ability to fine tune the configuration of requests via
   * {@link HttpClient#newRequest(URI)}.</p>
   * <p>{@link HttpClient} acts as a central configuration point for network parameters (such as idle timeouts)
   * and HTTP parameters (such as whether to follow redirects).</p>
   * <p>{@link HttpClient} transparently pools connections to servers, but allows direct control of connections
   * for cases where this is needed.</p>
   * <p>{@link HttpClient} also acts as a central configuration point for cookies, via {@link #getCookieStore()}.</p>
   * <p>Typical usage:</p>
   * <pre>
   * HttpClient httpClient = new HttpClient();
   * httpClient.start();
   *
   * // One liner:
   * httpClient.GET("http://localhost:8080/").get().status();
   *
   * // Building a request with a timeout
   * Response response = httpClient.newRequest("http://localhost:8080").send().get(5, TimeUnit.SECONDS);
   * int status = response.status();
   *
   * // Asynchronously
   * httpClient.newRequest("http://localhost:8080").send(new Response.CompleteListener()
   * {
   *     &#64;Override
   *     public void onComplete(Result result)
   *     {
   *         ...
   *     }
  * });
  * </pre>
  */
 public class HttpClient extends ContainerLifeCycle
 {
     private static final Logger LOG = Log.getLogger(HttpClient.class);
 
     private final ConcurrentMap<Origin, HttpDestination> destinations = new ConcurrentHashMap<>();
     private final ConcurrentMap<Long, HttpConversation> conversations = new ConcurrentHashMap<>();
     private final List<ProtocolHandler> handlers = new ArrayList<>();
     private final List<Request.Listener> requestListeners = new ArrayList<>();
     private final AuthenticationStore authenticationStore = new HttpAuthenticationStore();
     private final Set<ContentDecoder.Factory> decoderFactories = new ContentDecoderFactorySet();
     private final ProxyConfiguration proxyConfig = new ProxyConfiguration();
     private final HttpClientTransport transport;
     private final SslContextFactory sslContextFactory;
     private volatile CookieManager cookieManager;
     private volatile CookieStore cookieStore;
     private volatile Executor executor;
     private volatile ByteBufferPool byteBufferPool;
     private volatile Scheduler scheduler;
     private volatile SocketAddressResolver resolver;
     private volatile HttpField agentField = new HttpField(HttpHeader.USER_AGENT, "Jetty/" + Jetty.VERSION);
     private volatile boolean followRedirects = true;
     private volatile int maxConnectionsPerDestination = 64;
     private volatile int maxRequestsQueuedPerDestination = 1024;
     private volatile int requestBufferSize = 4096;
     private volatile int responseBufferSize = 16384;
     private volatile int maxRedirects = 8;
     private volatile SocketAddress bindAddress;
     private volatile long connectTimeout = 15000;
     private volatile long addressResolutionTimeout = 15000;
     private volatile long idleTimeout;
     private volatile boolean tcpNoDelay = true;
     private volatile boolean dispatchIO = true;
     private volatile boolean strictEventOrdering = false;
     private volatile HttpField encodingField;
 
     /**
      * Creates a {@link HttpClient} instance that can perform requests to non-TLS destinations only
      * (that is, requests with the "http" scheme only, and not "https").
      *
      * @see #HttpClient(SslContextFactory) to perform requests to TLS destinations.
      */
     public HttpClient()
     {
         this(null);
     }
 
     /**
      * Creates a {@link HttpClient} instance that can perform requests to non-TLS and TLS destinations
      * (that is, both requests with the "http" scheme and with the "https" scheme).
      *
      * @param sslContextFactory the {@link SslContextFactory} that manages TLS encryption
      * @see #getSslContextFactory()
      */
     public HttpClient(SslContextFactory sslContextFactory)
     {
         this(new HttpClientTransportOverHTTP(), sslContextFactory);
     }
 
     public HttpClient(HttpClientTransport transport, SslContextFactory sslContextFactory)
     {
         this.transport = transport;
         this.sslContextFactory = sslContextFactory;
     }
 
     public HttpClientTransport getTransport()
     {
         return transport;
     }
 
     /**
      * @return the {@link SslContextFactory} that manages TLS encryption
      * @see #HttpClient(SslContextFactory)
      */
     public SslContextFactory getSslContextFactory()
     {
         return sslContextFactory;
     }
 
     @Override
     protected void doStart() throws Exception
     {
         if (sslContextFactory != null)
             addBean(sslContextFactory);
 
         String name = HttpClient.class.getSimpleName() + "@" + hashCode();
 
         if (executor == null)
         {
             QueuedThreadPool threadPool = new QueuedThreadPool();
             threadPool.setName(name);
             executor = threadPool;
         }
         addBean(executor);
 
         if (byteBufferPool == null)
             byteBufferPool = new MappedByteBufferPool();
         addBean(byteBufferPool);
 
         if (scheduler == null)
             scheduler = new ScheduledExecutorScheduler(name + "-scheduler", false);
         addBean(scheduler);
 
         addBean(transport);
         transport.setHttpClient(this);
 
         resolver = new SocketAddressResolver(executor, scheduler, getAddressResolutionTimeout());
 
         handlers.add(new ContinueProtocolHandler(this));
         handlers.add(new RedirectProtocolHandler(this));
         handlers.add(new WWWAuthenticationProtocolHandler(this));
         handlers.add(new ProxyAuthenticationProtocolHandler(this));
 
         decoderFactories.add(new GZIPContentDecoder.Factory());
 
         cookieManager = newCookieManager();
         cookieStore = cookieManager.getCookieStore();
 
         super.doStart();
     }
 
     private CookieManager newCookieManager()
     {
         return new CookieManager(getCookieStore(), CookiePolicy.ACCEPT_ALL);
     }
 
     @Override
     protected void doStop() throws Exception
     {
         cookieStore.removeAll();
         cookieStore = null;
         decoderFactories.clear();
         handlers.clear();
 
         for (HttpDestination destination : destinations.values())
             destination.close();
         destinations.clear();
 
         conversations.clear();
         requestListeners.clear();
         authenticationStore.clearAuthentications();
         authenticationStore.clearAuthenticationResults();
 
         super.doStop();
     }
 
     /**
      * Returns a <em>non</em> thread-safe list of {@link org.eclipse.jetty.client.api.Request.Listener}s that can be modified before
      * performing requests.
      *
      * @return a list of {@link org.eclipse.jetty.client.api.Request.Listener} that can be used to add and remove listeners
      */
     public List<Request.Listener> getRequestListeners()
     {
         return requestListeners;
     }
 
     /**
      * @return the cookie store associated with this instance
      */
     public CookieStore getCookieStore()
     {
         return cookieStore;
     }
 
     /**
      * @param cookieStore the cookie store associated with this instance
      */
     public void setCookieStore(CookieStore cookieStore)
     {
         this.cookieStore = Objects.requireNonNull(cookieStore);
         this.cookieManager = newCookieManager();
     }
 
     /**
      * Keep this method package-private because its interface is so ugly
      * that we really don't want to expose it more than strictly needed.
      *
      * @return the cookie manager
      */
     CookieManager getCookieManager()
     {
         return cookieManager;
     }
 
     /**
      * @return the authentication store associated with this instance
      */
     public AuthenticationStore getAuthenticationStore()
     {
         return authenticationStore;
     }
 
     /**
      * Returns a <em>non</em> thread-safe set of {@link ContentDecoder.Factory}s that can be modified before
      * performing requests.
      *
      * @return a set of {@link ContentDecoder.Factory} that can be used to add and remove content decoder factories
      */
     public Set<ContentDecoder.Factory> getContentDecoderFactories()
     {
         return decoderFactories;
     }
 
     /**
      * Performs a GET request to the specified URI.
      *
      * @param uri the URI to GET
      * @return the {@link ContentResponse} for the request
      * @see #GET(URI)
      */
     public ContentResponse GET(String uri) throws InterruptedException, ExecutionException, TimeoutException
     {
         return GET(URI.create(uri));
     }
 
     /**
      * Performs a GET request to the specified URI.
      *
      * @param uri the URI to GET
      * @return the {@link ContentResponse} for the request
      * @see #newRequest(URI)
      */
     public ContentResponse GET(URI uri) throws InterruptedException, ExecutionException, TimeoutException
     {
         return newRequest(uri).send();
     }
 
     /**
      * Creates a POST request to the specified URI.
      *
      * @param uri the URI to POST to
      * @return the POST request
      * @see #POST(URI)
      */
     public Request POST(String uri)
     {
         return POST(URI.create(uri));
     }
 
     /**
      * Creates a POST request to the specified URI.
      *
      * @param uri the URI to POST to
      * @return the POST request
      */
     public Request POST(URI uri)
     {
         return newRequest(uri).method(HttpMethod.POST);
     }
 
     /**
      * Creates a new request with the "http" scheme and the specified host and port
      *
      * @param host the request host
      * @param port the request port
      * @return the request just created
      */
     public Request newRequest(String host, int port)
     {
         return newRequest(new Origin("http", host, port).asString());
     }
 
     /**
      * Creates a new request with the specified URI.
      *
      * @param uri the URI to request
      * @return the request just created
      */
     public Request newRequest(String uri)
     {
         return newRequest(URI.create(uri));
     }
 
     /**
      * Creates a new request with the specified URI.
      *
      * @param uri the URI to request
      * @return the request just created
      */
     public Request newRequest(URI uri)
     {
         return new HttpRequest(this, uri);
     }
 
     protected Request copyRequest(Request oldRequest, URI newURI)
     {
         Request newRequest = new HttpRequest(this, oldRequest.getConversationID(), newURI);
         newRequest.method(oldRequest.getMethod())
                 .version(oldRequest.getVersion())
                 .content(oldRequest.getContent())
                 .idleTimeout(oldRequest.getIdleTimeout(), TimeUnit.MILLISECONDS)
                 .timeout(oldRequest.getTimeout(), TimeUnit.MILLISECONDS)
                 .followRedirects(oldRequest.isFollowRedirects());
         for (HttpField header : oldRequest.getHeaders())
         {
             // We have a new URI, so skip the host header if present
             if (HttpHeader.HOST == header.getHeader())
                 continue;
 
             // Remove expectation headers
             if (HttpHeader.EXPECT == header.getHeader())
                 continue;
 
             // Remove cookies
             if (HttpHeader.COOKIE == header.getHeader())
                 continue;
 
             // Remove authorization headers
             if (HttpHeader.AUTHORIZATION == header.getHeader() ||
                     HttpHeader.PROXY_AUTHORIZATION == header.getHeader())
                 continue;
 
             newRequest.header(header.getName(), header.getValue());
         }
         return newRequest;
     }
 
     /**
      * Returns a {@link Destination} for the given scheme, host and port.
      * Applications may use {@link Destination}s to create {@link Connection}s
      * that will be outside {@link HttpClient}'s pooling mechanism, to explicitly
      * control the connection lifecycle (in particular their termination with
      * {@link Connection#close()}).
      *
      * @param scheme the destination scheme
      * @param host the destination host
      * @param port the destination port
      * @return the destination
      * @see #getDestinations()
      */
     public Destination getDestination(String scheme, String host, int port)
     {
         return destinationFor(scheme, host, port);
     }
 
     protected HttpDestination destinationFor(String scheme, String host, int port)
     {
         port = normalizePort(scheme, port);
 
         Origin origin = new Origin(scheme, host, port);
         HttpDestination destination = destinations.get(origin);
         if (destination == null)
         {
             destination = transport.newHttpDestination(origin);
             if (isRunning())
             {
                 HttpDestination existing = destinations.putIfAbsent(origin, destination);
                 if (existing != null)
                     destination = existing;
                 else
                     LOG.debug("Created {}", destination);
                 if (!isRunning())
                     destinations.remove(origin);
             }
 
         }
         return destination;
     }
 
     /**
      * @return the list of destinations known to this {@link HttpClient}.
      */
     public List<Destination> getDestinations()
     {
         return new ArrayList<Destination>(destinations.values());
     }
 
     protected void send(final Request request, List<Response.ResponseListener> listeners)
     {
         String scheme = request.getScheme().toLowerCase(Locale.ENGLISH);
         if (!HttpScheme.HTTP.is(scheme) && !HttpScheme.HTTPS.is(scheme))
             throw new IllegalArgumentException("Invalid protocol " + scheme);
 
         HttpDestination destination = destinationFor(scheme, request.getHost(), request.getPort());
         destination.send(request, listeners);
     }
 
     protected void newConnection(final HttpDestination destination, final Promise<Connection> promise)
     {
         Origin.Address address = destination.getConnectAddress();
         resolver.resolve(address.getHost(), address.getPort(), new Promise<SocketAddress>()
         {
             @Override
             public void succeeded(SocketAddress socketAddress)
             {
                 Map<String, Object> context = new HashMap<>();
                 context.put(HttpClientTransport.HTTP_DESTINATION_CONTEXT_KEY, destination);
                 context.put(HttpClientTransport.HTTP_CONNECTION_PROMISE_CONTEXT_KEY, promise);
                 transport.connect(socketAddress, context);
             }
 
             @Override
             public void failed(Throwable x)
             {
                 promise.failed(x);
             }
         });
     }
 
     protected HttpConversation getConversation(long id, boolean create)
     {
         HttpConversation conversation = conversations.get(id);
         if (conversation == null && create)
         {
             conversation = new HttpConversation(this, id);
             HttpConversation existing = conversations.putIfAbsent(id, conversation);
             if (existing != null)
                 conversation = existing;
             else
                 LOG.debug("{} created", conversation);
         }
         return conversation;
     }
 
     protected void removeConversation(HttpConversation conversation)
     {
         conversations.remove(conversation.getID());
         LOG.debug("{} removed", conversation);
     }
 
     protected List<ProtocolHandler> getProtocolHandlers()
     {
         return handlers;
     }
 
     protected ProtocolHandler findProtocolHandler(Request request, Response response)
     {
         // Optimized to avoid allocations of iterator instances
         List<ProtocolHandler> protocolHandlers = getProtocolHandlers();
         for (int i = 0; i < protocolHandlers.size(); ++i)
         {
             ProtocolHandler handler = protocolHandlers.get(i);
             if (handler.accept(request, response))
                 return handler;
         }
         return null;
     }
 
     /**
      * @return the {@link ByteBufferPool} of this {@link HttpClient}
      */
     public ByteBufferPool getByteBufferPool()
     {
         return byteBufferPool;
     }
 
     /**
      * @param byteBufferPool the {@link ByteBufferPool} of this {@link HttpClient}
      */
     public void setByteBufferPool(ByteBufferPool byteBufferPool)
     {
         this.byteBufferPool = byteBufferPool;
     }
 
     /**
      * @return the max time, in milliseconds, a connection can take to connect to destinations
      */
     public long getConnectTimeout()
     {
         return connectTimeout;
     }
 
     /**
      * @param connectTimeout the max time, in milliseconds, a connection can take to connect to destinations
      * @see java.net.Socket#connect(SocketAddress, int)
      */
     public void setConnectTimeout(long connectTimeout)
     {
         this.connectTimeout = connectTimeout;
     }
 
     /**
      * @return the timeout, in milliseconds, for the DNS resolution of host addresses
      */
     public long getAddressResolutionTimeout()
     {
         return addressResolutionTimeout;
     }
 
     /**
      * @param addressResolutionTimeout the timeout, in milliseconds, for the DNS resolution of host addresses
      */
     public void setAddressResolutionTimeout(long addressResolutionTimeout)
     {
         this.addressResolutionTimeout = addressResolutionTimeout;
     }
 
     /**
      * @return the max time, in milliseconds, a connection can be idle (that is, without traffic of bytes in either direction)
      */
     public long getIdleTimeout()
     {
         return idleTimeout;
     }
 
     /**
      * @param idleTimeout the max time, in milliseconds, a connection can be idle (that is, without traffic of bytes in either direction)
      */
     public void setIdleTimeout(long idleTimeout)
     {
         this.idleTimeout = idleTimeout;
     }
 
     /**
      * @return the address to bind socket channels to
      * @see #setBindAddress(SocketAddress)
      */
     public SocketAddress getBindAddress()
     {
         return bindAddress;
     }
 
     /**
      * @param bindAddress the address to bind socket channels to
      * @see #getBindAddress()
      * @see SocketChannel#bind(SocketAddress)
      */
     public void setBindAddress(SocketAddress bindAddress)
     {
         this.bindAddress = bindAddress;
     }
 
     /**
      * @return the "User-Agent" HTTP field of this {@link HttpClient}
      */
     public HttpField getUserAgentField()
     {
         return agentField;
     }
 
     /**
      * @param agent the "User-Agent" HTTP header string of this {@link HttpClient}
      */
     public void setUserAgentField(HttpField agent)
     {
         if (agent.getHeader() != HttpHeader.USER_AGENT)
             throw new IllegalArgumentException();
         this.agentField = agent;
     }
 
     /**
      * @return whether this {@link HttpClient} follows HTTP redirects
      * @see Request#isFollowRedirects()
      */
     public boolean isFollowRedirects()
     {
         return followRedirects;
     }
 
     /**
      * @param follow whether this {@link HttpClient} follows HTTP redirects
      * @see #setMaxRedirects(int)
      */
     public void setFollowRedirects(boolean follow)
     {
         this.followRedirects = follow;
     }
 
     /**
      * @return the {@link Executor} of this {@link HttpClient}
      */
     public Executor getExecutor()
     {
         return executor;
     }
 
     /**
      * @param executor the {@link Executor} of this {@link HttpClient}
      */
     public void setExecutor(Executor executor)
     {
         this.executor = executor;
     }
 
     /**
      * @return the {@link Scheduler} of this {@link HttpClient}
      */
     public Scheduler getScheduler()
     {
         return scheduler;
     }
 
     /**
      * @param scheduler the {@link Scheduler} of this {@link HttpClient}
      */
     public void setScheduler(Scheduler scheduler)
     {
         this.scheduler = scheduler;
     }
 
     /**
      * @return the max number of connections that this {@link HttpClient} opens to {@link Destination}s
      */
     public int getMaxConnectionsPerDestination()
     {
         return maxConnectionsPerDestination;
     }
 
     /**
      * Sets the max number of connections to open to each destinations.
      * <p />
      * RFC 2616 suggests that 2 connections should be opened per each destination,
      * but browsers commonly open 6.
      * If this {@link HttpClient} is used for load testing, it is common to have only one destination
      * (the server to load test), and it is recommended to set this value to a high value (at least as
      * much as the threads present in the {@link #getExecutor() executor}).
      *
      * @param maxConnectionsPerDestination the max number of connections that this {@link HttpClient} opens to {@link Destination}s
      */
     public void setMaxConnectionsPerDestination(int maxConnectionsPerDestination)
     {
         this.maxConnectionsPerDestination = maxConnectionsPerDestination;
     }
 
     /**
      * @return the max number of requests that may be queued to a {@link Destination}.
      */
     public int getMaxRequestsQueuedPerDestination()
     {
         return maxRequestsQueuedPerDestination;
     }
 
     /**
      * Sets the max number of requests that may be queued to a destination.
      * <p />
      * If this {@link HttpClient} performs a high rate of requests to a destination,
      * and all the connections managed by that destination are busy with other requests,
      * then new requests will be queued up in the destination.
      * This parameter controls how many requests can be queued before starting to reject them.
      * If this {@link HttpClient} is used for load testing, it is common to have this parameter
      * set to a high value, although this may impact latency (requests sit in the queue for a long
      * time before being sent).
      *
      * @param maxRequestsQueuedPerDestination the max number of requests that may be queued to a {@link Destination}.
      */
     public void setMaxRequestsQueuedPerDestination(int maxRequestsQueuedPerDestination)
     {
         this.maxRequestsQueuedPerDestination = maxRequestsQueuedPerDestination;
     }
 
     /**
      * @return the size of the buffer used to write requests
      */
     public int getRequestBufferSize()
     {
         return requestBufferSize;
     }
 
     /**
      * @param requestBufferSize the size of the buffer used to write requests
      */
     public void setRequestBufferSize(int requestBufferSize)
     {
         this.requestBufferSize = requestBufferSize;
     }
 
     /**
      * @return the size of the buffer used to read responses
      */
     public int getResponseBufferSize()
     {
         return responseBufferSize;
     }
 
     /**
      * @param responseBufferSize the size of the buffer used to read responses
      */
     public void setResponseBufferSize(int responseBufferSize)
     {
         this.responseBufferSize = responseBufferSize;
     }
 
     /**
      * @return the max number of HTTP redirects that are followed
      * @see #setMaxRedirects(int)
      */
     public int getMaxRedirects()
     {
         return maxRedirects;
     }
 
     /**
      * @param maxRedirects the max number of HTTP redirects that are followed
      * @see #setFollowRedirects(boolean)
      */
     public void setMaxRedirects(int maxRedirects)
     {
         this.maxRedirects = maxRedirects;
     }
 
     /**
      * @return whether TCP_NODELAY is enabled
      */
     public boolean isTCPNoDelay()
     {
         return tcpNoDelay;
     }
 
     /**
      * @param tcpNoDelay whether TCP_NODELAY is enabled
      * @see java.net.Socket#setTcpNoDelay(boolean)
      */
     public void setTCPNoDelay(boolean tcpNoDelay)
     {
         this.tcpNoDelay = tcpNoDelay;
     }
 
     /**
      * @return true to dispatch I/O operations in a different thread, false to execute them in the selector thread
      * @see #setDispatchIO(boolean)
      */
     public boolean isDispatchIO()
     {
         return dispatchIO;
     }
 
     /**
      * Whether to dispatch I/O operations from the selector thread to a different thread.
      * <p />
      * This implementation never blocks on I/O operation, but invokes application callbacks that may
      * take time to execute or block on other I/O.
      * If application callbacks are known to take time or block on I/O, then parameter {@code dispatchIO}
      * should be set to true.
      * If application callbacks are known to be quick and never block on I/O, then parameter {@code dispatchIO}
      * may be set to false.
      *
      * @param dispatchIO true to dispatch I/O operations in a different thread,
      *                   false to execute them in the selector thread
      */
     public void setDispatchIO(boolean dispatchIO)
     {
         this.dispatchIO = dispatchIO;
     }
 
     /**
      * @return whether request events must be strictly ordered
      */
     public boolean isStrictEventOrdering()
     {
         return strictEventOrdering;
     }
 
     /**
      * Whether request events must be strictly ordered.
      * <p />
      * {@link org.eclipse.jetty.client.api.Response.CompleteListener}s may send a second request.
      * If the second request is for the same destination, there is an inherent race
      * condition for the use of the connection: the first request may still be associated with the
      * connection, so the second request cannot use that connection and is forced to open another one.
      * <p />
      * From the point of view of connection usage, the connection is reusable just before the "complete"
      * event, so it would be possible to reuse that connection from {@link org.eclipse.jetty.client.api.Response.CompleteListener}s;
      * but in this case the second request's events will fire before the "complete" events of the first
      * request.
      * <p />
      * This setting enforces strict event ordering so that a "begin" event of a second request can never
      * fire before the "complete" event of a first request, but at the expense of an increased usage
      * of connections.
      * <p />
      * When not enforced, a "begin" event of a second request may happen before the "complete" event of
      * a first request and allow for better usage of connections.
      *
      * @param strictEventOrdering whether request events must be strictly ordered
      */
     public void setStrictEventOrdering(boolean strictEventOrdering)
     {
         this.strictEventOrdering = strictEventOrdering;
     }
 
     /**
      * @return the forward proxy configuration
      */
     public ProxyConfiguration getProxyConfiguration()
     {
         return proxyConfig;
     }
 
     protected HttpField getAcceptEncodingField()
     {
         return encodingField;
     }
 
     protected String normalizeHost(String host)
     {
         if (host != null && host.matches("\\[.*\\]"))
             return host.substring(1, host.length() - 1);
         return host;
     }
 
     protected int normalizePort(String scheme, int port)
     {
         return port > 0 ? port : HttpScheme.HTTPS.is(scheme) ? 443 : 80;
     }
 
     protected boolean isDefaultPort(String scheme, int port)
     {
         return HttpScheme.HTTPS.is(scheme) ? port == 443 : port == 80;
     }
 
     @Override
     public void dump(Appendable out, String indent) throws IOException
     {
         dumpThis(out);
         dump(out, indent, getBeans(), destinations.values());
     }
 
     private class ContentDecoderFactorySet implements Set<ContentDecoder.Factory>
     {
         private final Set<ContentDecoder.Factory> set = new HashSet<>();
 
         @Override
         public boolean add(ContentDecoder.Factory e)
         {
             boolean result = set.add(e);
             invalidate();
             return result;
         }
 
         @Override
         public boolean addAll(Collection<? extends ContentDecoder.Factory> c)
         {
             boolean result = set.addAll(c);
             invalidate();
             return result;
         }
 
         @Override
         public boolean remove(Object o)
         {
             boolean result = set.remove(o);
             invalidate();
             return result;
         }
 
         @Override
         public boolean removeAll(Collection<?> c)
         {
             boolean result = set.removeAll(c);
             invalidate();
             return result;
         }
 
         @Override
         public boolean retainAll(Collection<?> c)
         {
             boolean result = set.retainAll(c);
             invalidate();
             return result;
         }
 
         @Override
         public void clear()
         {
             set.clear();
             invalidate();
         }
 
         @Override
         public int size()
         {
             return set.size();
         }
 
         @Override
         public boolean isEmpty()
         {
             return set.isEmpty();
         }
 
         @Override
         public boolean contains(Object o)
         {
             return set.contains(o);
         }
 
         @Override
         public boolean containsAll(Collection<?> c)
         {
             return set.containsAll(c);
         }
 
         @Override
         public Iterator<ContentDecoder.Factory> iterator()
         {
             return set.iterator();
         }
 
         @Override
         public Object[] toArray()
         {
             return set.toArray();
         }
 
         @Override
         public <T> T[] toArray(T[] a)
         {
             return set.toArray(a);
         }
 
         protected void invalidate()
         {
             if (set.isEmpty())
             {
                 encodingField = null;
             }
             else
             {
                 StringBuilder value = new StringBuilder();
                 for (Iterator<ContentDecoder.Factory> iterator = set.iterator(); iterator.hasNext();)
                 {
                     ContentDecoder.Factory decoderFactory = iterator.next();
                     value.append(decoderFactory.getEncoding());
                     if (iterator.hasNext())
                         value.append(",");
                 }
                 encodingField = new HttpField(HttpHeader.ACCEPT_ENCODING, value.toString());
             }
         }
     }
 }