/*
    * ====================================================================
    * 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.impl.nio.reactor;
  
  import java.io.IOException;
  
  import org.apache.http.annotation.Immutable;
  import org.apache.http.nio.reactor.IOEventDispatch;
  import org.apache.http.nio.reactor.IOSession;
  import org.apache.http.nio.reactor.ssl.SSLIOSession;
  
  /**
   * Abstract {@link IOEventDispatch} implementation that supports both plain (non-encrypted)
   * and SSL encrypted HTTP connections.
   *
   * @param <T> the connection type.
   * @since 4.2
   */
  @Immutable // provided injected dependencies are immutable
  public abstract class AbstractIODispatch<T> implements IOEventDispatch {
  
      protected abstract T createConnection(IOSession session);
  
      protected abstract void onConnected(T conn);
  
      protected abstract void onClosed(T conn);
  
      protected abstract void onException(T conn, IOException ex);
  
      protected abstract void onInputReady(T conn);
  
      protected abstract void onOutputReady(T conn);
  
      protected abstract void onTimeout(T conn);
  
      private void ensureNotNull(final T conn) {
          if (conn == null) {
              throw new IllegalStateException("HTTP connection is null");
          }
      }
  
      public void connected(final IOSession session) {
          @SuppressWarnings("unchecked")
          T conn = (T) session.getAttribute(IOEventDispatch.CONNECTION_KEY);
          try {
              if (conn == null) {
                  conn = createConnection(session);
                  session.setAttribute(IOEventDispatch.CONNECTION_KEY, conn);
              }
              onConnected(conn);
              SSLIOSession ssliosession = (SSLIOSession) session.getAttribute(
                      SSLIOSession.SESSION_KEY);
              if (ssliosession != null) {
                  try {
                      synchronized (ssliosession) {
                          if (!ssliosession.isInitialized()) {
                              ssliosession.initialize();
                          }
                      }
                  } catch (IOException ex) {
                      onException(conn, ex);
                      ssliosession.shutdown();
                  }
              }
          } catch (RuntimeException ex) {
              session.shutdown();
              throw ex;
          }
      }
  
      public void disconnected(final IOSession session) {
          @SuppressWarnings("unchecked")
          T conn = (T) session.getAttribute(IOEventDispatch.CONNECTION_KEY);
          if (conn != null) {
             onClosed(conn);
         }
     }
 
     public void inputReady(final IOSession session) {
         @SuppressWarnings("unchecked")
         T conn = (T) session.getAttribute(IOEventDispatch.CONNECTION_KEY);
         try {
             ensureNotNull(conn);
             SSLIOSession ssliosession = (SSLIOSession) session.getAttribute(
                     SSLIOSession.SESSION_KEY);
             if (ssliosession == null) {
                 onInputReady(conn);
             } else {
                 try {
                     if (!ssliosession.isInitialized()) {
                         ssliosession.initialize();
                     }
                     if (ssliosession.isAppInputReady()) {
                         onInputReady(conn);
                     }
                     ssliosession.inboundTransport();
                 } catch (IOException ex) {
                     onException(conn, ex);
                     ssliosession.shutdown();
                 }
             }
         } catch (RuntimeException ex) {
             session.shutdown();
             throw ex;
         }
     }
 
     public void outputReady(final IOSession session) {
         @SuppressWarnings("unchecked")
         T conn = (T) session.getAttribute(IOEventDispatch.CONNECTION_KEY);
         try {
             ensureNotNull(conn);
             SSLIOSession ssliosession = (SSLIOSession) session.getAttribute(
                     SSLIOSession.SESSION_KEY);
             if (ssliosession == null) {
                 onOutputReady(conn);
             } else {
                 try {
                     if (!ssliosession.isInitialized()) {
                         ssliosession.initialize();
                     }
                     if (ssliosession.isAppOutputReady()) {
                         onOutputReady(conn);
                     }
                     ssliosession.outboundTransport();
                 } catch (IOException ex) {
                     onException(conn, ex);
                     ssliosession.shutdown();
                 }
             }
         } catch (RuntimeException ex) {
             session.shutdown();
             throw ex;
         }
     }
 
     public void timeout(final IOSession session) {
         @SuppressWarnings("unchecked")
         T conn = (T) session.getAttribute(IOEventDispatch.CONNECTION_KEY);
         try {
             SSLIOSession ssliosession = (SSLIOSession) session.getAttribute(
                     SSLIOSession.SESSION_KEY);
             ensureNotNull(conn);
             onTimeout(conn);
             if (ssliosession != null) {
                 synchronized (ssliosession) {
                     if (ssliosession.isOutboundDone() && !ssliosession.isInboundDone()) {
                         // The session failed to terminate cleanly
                         ssliosession.shutdown();
                     }
                 }
             }
         } catch (RuntimeException ex) {
             session.shutdown();
             throw ex;
         }
     }
 
 }