ChangeLogTag:Wed Jun 21 15:51:10 2000 Ossama Othman <ossama@uci.edu>

27 files changed, 454 insertions, 593 deletions

diff --git a/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.cpp b/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.cpp
index 5aefbf685b8..8b253015f81 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.cpp
+++ b/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.cpp
@@ -6,7 +6,7 @@
 #include "ace/FILE_Connector.h"
 #include "Content_Iterator_i.h"
 
-ACE_RCSID(AMI_Iterator, Content_Iterator_i, "$Id$")
+ACE_RCSID (AMI_Iterator, Content_Iterator_i, "$Id$")
 
 Content_Iterator_i::Content_Iterator_i (const char *pathname,
                                         CORBA::ULong file_size)
diff --git a/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.h b/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.h
index 607ee9a9d5f..e85a263dcfa 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.h
+++ b/TAO/examples/Content_Server/AMI_Iterator/Content_Iterator_i.h
@@ -5,7 +5,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     ECE255
+//     AMI_Iterator
 //
 // = FILENAME
 //     Content_Iterator_i.h
@@ -32,28 +32,36 @@
 class Content_Iterator_i :
   public virtual POA_Web_Server::Content_Iterator,
   public virtual PortableServer::RefCountServantBase
-  // = TITLE
-  //Implement the Web_Server::Content_Iterator interface.
 {
+  // = TITLE
+  //    Implement the Web_Server::Content_Iterator interface.
+  //
+  // = DESCRIPTION
+  //    This class implements the Iterator pattern to minimize memory
+  //    requirements when retrieving data from a content server.
+  //    Rather than retrieving one large chunk of data, this class
+  //    iterates on the server so that smaller chunks of data are
+  //    retrieved.
+
   friend class Iterator_Factory_i;
 public:
 
-  // Constructor
   Content_Iterator_i (const char *filename, CORBA::ULong file_size);
+  // Constructor
 
-  // Destructor
   ~Content_Iterator_i (void);
+  // Destructor
 
-  // This operation returns the next <chunk> of the file starting at
-  // <offset>.  If there are no more bindings, false is returned.
   virtual CORBA::Boolean next_chunk (CORBA::ULong offset,
                                      Web_Server::Chunk_Type_out chunk,
                                      CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException));
+  // This operation returns the next <chunk> of the file starting at
+  // <offset>.  If there are no more bindings, false is returned.
 
-  // Destroy the iterator.
   virtual void destroy (CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException));
+  // Destroy the iterator.
 
 private:
 
diff --git a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.cpp b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.cpp
index 32e2c07d1ba..6ea2ce3711a 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.cpp
+++ b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.cpp
@@ -6,7 +6,7 @@
 #include "Content_Iterator_i.h"
 #include "Iterator_Factory_i.h"
 
-ACE_RCSID(AMI_Iterator, Iterator_Factory_i, "$Id$")
+ACE_RCSID (AMI_Iterator, Iterator_Factory_i, "$Id$")
 
 void
 Iterator_Factory_i::get_iterator (const char *pathname,
@@ -15,8 +15,6 @@ Iterator_Factory_i::get_iterator (const char *pathname,
                                   CORBA::Environment &ACE_TRY_ENV)
   ACE_THROW_SPEC ((CORBA::SystemException, Web_Server::Error_Result))
 {
-  // Based on code available in H&V.
-
   ACE_DEBUG ((LM_DEBUG,
               ACE_TEXT ("Received request for file: <%s>\n"),
               pathname));
@@ -26,8 +24,12 @@ Iterator_Factory_i::get_iterator (const char *pathname,
     // HTTP 1.1 "Internal Server Error".
     ACE_THROW (Web_Server::Error_Result (500));
 
-  Content_Iterator_i *iterator_servant =
-    new Content_Iterator_i (pathname, file_status.st_size);
+  Content_Iterator_i *iterator_servant = 0;
+  ACE_NEW_THROW_EX (iterator_servant,
+                    Content_Iterator_i (pathname,
+                                        file_status.st_size),
+                    CORBA::NO_MEMORY ());
+  ACE_CHECK;
 
   if (iterator_servant->init () != 0)
     {
@@ -45,7 +47,13 @@ Iterator_Factory_i::get_iterator (const char *pathname,
     iterator_servant->_this (ACE_TRY_ENV);
   ACE_CHECK;
 
-  metadata = new Web_Server::Metadata_Type;
+  Web_Server::Metadata_Type *tmp = 0;
+  ACE_NEW_THROW_EX (tmp,
+                    Web_Server::Metadata_Type,
+                    CORBA::NO_MEMORY ());
+  ACE_CHECK;
+  
+  metadata = tmp;
 
   if (this->modification_date (&file_status,
                                metadata) != 0)
diff --git a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.h b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.h
index 69b3fa995b9..9111434603d 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.h
+++ b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Factory_i.h
@@ -4,7 +4,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     ECE255
+//     AMI_Iterator
 //
 // = FILENAME
 //     Iterator_Factory_i.h
@@ -34,28 +34,33 @@ class Content_Iterator_i;
 class Iterator_Factory_i : virtual public POA_Web_Server::Iterator_Factory
 {
   // = TITLE
-  //   Implement the Web_Server::Iterator_Factory interface.
+  //    Factory that creates a Content_Iterator that retrieves fixed
+  //    size chunks of data from Content server.
+  //
+  // = DESCRIPTION
+  //    This class creates a Content_Iterator that is set up to
+  //    iteratively download a specific file.  This same factory can
+  //    be used to create Content_Iterators for other files.
 public:
 
-  // This factory method returns a <Content_Iterator> that can be used
-  // to read the <contents> associated with <pathname> one ``chunk''
-  // at a time.  The <metadata> reports information about the
-  // <contents>.
   virtual void get_iterator (const char *pathname,
                              Web_Server::Content_Iterator_out contents,
                              Web_Server::Metadata_Type_out metadata,
                              CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException,
                      Web_Server::Error_Result));
+  // This factory method returns a <Content_Iterator> that can be used
+  // to read the <contents> associated with <pathname> one ``chunk''
+  // at a time.  The <metadata> reports information about the
+  // <contents>.
 
-  // Set the file modification date in the metadata structure.
   int modification_date (struct stat *file_status,
                          Web_Server::Metadata_Type_out metadata);
+  // Set the file modification date in the metadata structure.
 
-  // Set the type of file content in the metadata structure.
   int content_type (const char *filename,
                     Web_Server::Metadata_Type_out metadata);
-
+  // Set the type of file content in the metadata structure.
 };
 
 #endif  /* ITERATOR_FACTORY_I_H */
diff --git a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Handler.h b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Handler.h
index 4b653122a89..5d3755b2c0c 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/Iterator_Handler.h
+++ b/TAO/examples/Content_Server/AMI_Iterator/Iterator_Handler.h
@@ -4,7 +4,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     Content_Server
+//     AMI_Iterator
 //
 // = FILENAME
 //     Iterator_Handler.h
@@ -21,8 +21,6 @@
 #ifndef ITERATOR_HANDLER_H
 #define ITERATOR_HANDLER_H
 
-#include "ace/pre.h"
-
 #include "ace/FILE_Addr.h"
 #include "ace/FILE_IO.h"
 #include "Web_ServerS.h"
@@ -31,14 +29,25 @@
 # pragma once
 #endif /* ACE_LACKS_PRAGMA_ONCE */
 
-// Dummy class to quiet down a warning.
-class Iterator_Handler_Friend;
 
 class Iterator_Handler
   : public virtual POA_Web_Server::AMI_Content_IteratorHandler,
     public virtual PortableServer::RefCountServantBase
 {
-  friend Iterator_Handler_Friend;
+  // = TITLE
+  //    The AMI reply handler for replies from the Content_Iterator.
+  //
+  // = DESCRIPTION
+  //    This class handles all asynchronously received replies from
+  //    the Content_Iterator on the server side.  Once a reply is
+  //    handled, another asynchronous request is made to the
+  //    Content_Iterator.  This ensures that chunks of data are
+  //    received in the proper order, and also takes advantage of
+  //    asyncronous method invocations.
+
+  friend class Iterator_Handler_Friend;
+  // Dummy friend class declaration to quiet down a warning.
+
 public:
 
   Iterator_Handler (void);
@@ -73,6 +82,7 @@ public:
   // pointer itself) of the <request_count> parameter will be
   // incremented when file retrieval begins, and decremented when file
   // retrieval completes.
+
 private:
   ~Iterator_Handler (void);
   // Destructor (private to ensure that Iterator_Handler is allocated
@@ -126,6 +136,4 @@ private:
   // decremented when file retrieval has completed.
 };
 
-#include "ace/post.h"
-
 #endif  /* ITERATOR_HAHNDLER_H */
diff --git a/TAO/examples/Content_Server/AMI_Iterator/client.cpp b/TAO/examples/Content_Server/AMI_Iterator/client.cpp
index 65ab63ee97c..179a392d48b 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/client.cpp
+++ b/TAO/examples/Content_Server/AMI_Iterator/client.cpp
@@ -8,7 +8,7 @@
 #include "Web_ServerC.h"
 #include "Iterator_Handler.h"
 
-ACE_RCSID(AMI_Iterator, client, "$Id")
+ACE_RCSID (AMI_Iterator, client, "$Id$")
 
 // Obtain reference to Iterator_Factory
 Web_Server::Iterator_Factory_ptr
@@ -55,7 +55,7 @@ main (int argc, char *argv[])
       mgr->activate (ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
-      // Now narrow to an Iterator_Factory reference.
+      // Get an Iterator_Factory reference.
       Web_Server::Iterator_Factory_var factory =
         ::get_iterator (orb.in (),
                         ACE_TRY_ENV);
@@ -137,7 +137,7 @@ get_iterator (CORBA::ORB_ptr o,
   ACE_CHECK_RETURN (Web_Server::Iterator_Factory::_nil ());
 
   // Narrow to a Naming Context
-  CosNaming::NamingContext_var nc = 
+  CosNaming::NamingContext_var nc =
     CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
   ACE_CHECK_RETURN (Web_Server::Iterator_Factory::_nil ());
 
@@ -182,7 +182,7 @@ void invoke_requests (int argc,
                         Iterator_Handler,
                         CORBA::NO_MEMORY ());
       ACE_CHECK;
-      
+
       // Transfer ownership to the POA.
       PortableServer::ServantBase_var tmp (handler);
 
diff --git a/TAO/examples/Content_Server/AMI_Iterator/server.cpp b/TAO/examples/Content_Server/AMI_Iterator/server.cpp
index e6a1262a669..3db1745290b 100644
--- a/TAO/examples/Content_Server/AMI_Iterator/server.cpp
+++ b/TAO/examples/Content_Server/AMI_Iterator/server.cpp
@@ -8,7 +8,7 @@
 
 #include "Iterator_Factory_i.h"
 
-ACE_RCSID(AMI_Iterator, server, "$Id$")
+ACE_RCSID (AMI_Iterator, server, "$Id$")
 
 int
 main (int argc, char *argv[])
@@ -51,7 +51,7 @@ main (int argc, char *argv[])
       ACE_TRY_CHECK;
 
       // Narrow to a Naming Context
-      CosNaming::NamingContext_var nc = 
+      CosNaming::NamingContext_var nc =
         CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback.cpp b/TAO/examples/Content_Server/AMI_Observer/Callback.cpp
deleted file mode 100644
index 6e473ea41ba..00000000000
--- a/TAO/examples/Content_Server/AMI_Observer/Callback.cpp
+++ /dev/null
@@ -1,296 +0,0 @@
-// -*- C++ -*-
-// $Id$
-
-// Ossama Othman <ossama@uci.edu>
-
-#include "ace/FILE_Connector.h"
-#include "ace/Log_Msg.h"
-#include "ace/Process_Manager.h"
-#include "ace/Synch.h"
-#include "Callback.h"
-
-ACE_RCSID(AMI_Observer, Callback, "$Id$")
-
-Callback_i::Callback_i (int *request_count)
-  : file_ (ACE_sap_any_cast (ACE_FILE_Addr &)),
-    file_io_ (),
-    ami_handler_ (),
-    metadata_ (),
-    last_chunk_ (0),
-    lock_ (),
-    request_count_ (request_count)
-{
-  // Create a temporary file to store the retrieved data.
-  ACE_FILE_Connector connector;
-
-  if (connector.connect (this->file_io_,
-                         this->file_,
-                         0,
-                         ACE_Addr::sap_any,
-                         0,
-                         O_CREAT | O_TRUNC | O_WRONLY,
-                         S_IRUSR | S_IWUSR) == -1)
-    {
-      ACE_ERROR ((LM_ERROR,
-                  ACE_TEXT ("%p\n"),
-                  ACE_TEXT ("Could not open file %s"),
-                  this->file_.get_path_name ()));
-    }
-  else
-    (*this->request_count_)++;
-}
-
-Callback_i::~Callback_i (void)
-{
-  (void) this->file_io_.close ();
-}
-
-void
-Callback_i::next_chunk (const Web_Server::Chunk_Type & chunk_data,
-                        CORBA::Boolean last_chunk,
-                        CORBA::Environment &ACE_TRY_ENV)
-  ACE_THROW_SPEC ((CORBA::SystemException))
-{
-  if (!last_chunk)
-    {
-      Web_Server::Chunk_Type_var chunk = chunk_data;
-
-      // Append the received data to the corresponding
-      // buffer/temporary file.
-      if (this->file_io_.send (chunk->get_buffer (),
-                               chunk->length ()) == -1)
-        {
-          (*this->request_count_)--;  // Don't wait for more data.
-
-          ACE_ERROR ((LM_ERROR,
-                      ACE_TEXT ("%p\n"),
-                      ACE_TEXT ("Unable to write retrieved data to ")
-                      ACE_TEXT ("file <%s>"),
-                      this->file_.get_path_name ()));
-          return;
-        }
-    }
-  else
-    {
-      {
-        ACE_MT (ACE_GUARD (ACE_SYNCH_MUTEX,
-                           guard,
-                           this->lock_));
-
-        this->last_chunk_ = 1;  // Received entire content.
-      }
-
-      ACE_DEBUG ((LM_INFO,
-                  ACE_TEXT ("Wrote retrieved data to file <%s>\n"),
-                  this->file_.get_path_name ()));
-
-      (*this->request_count_)--;  // No more data.
-
-      // File retrieval has completed, so spawn an external viewer to
-      // display its contents.
-
-      // If the entire metadata has been received, then spawn an
-      // external viewer to display the received file.
-      if (this->metadata_received ())
-        {
-          (void) this->file_io_.close ();
-          this->deactivate (ACE_TRY_ENV);
-          ACE_CHECK;
-
-          (void) this->spawn_viewer ();
-        }
-    }
-}
-
-void
-Callback_i::metadata (const Web_Server::Metadata_Type &metadata)
-{
-  ACE_DECLARE_NEW_CORBA_ENV;
-  ACE_TRY
-    {
-      {
-        ACE_MT (ACE_GUARD (ACE_SYNCH_MUTEX,
-                           guard,
-                           this->lock_));
-        this->metadata_ = metadata;
-      }
-
-      ACE_DEBUG ((LM_INFO,
-                  ACE_TEXT ("Retrieved file has the following ")
-                  ACE_TEXT ("characteristics:\n")
-                  ACE_TEXT ("  Modification Date: %s\n")
-                  ACE_TEXT ("  Content Type: %s\n"),
-                  this->metadata_.modification_date.in (),
-                  this->metadata_.content_type.in ()));
-
-      // If the entire content of the data has been received, then spawn
-      // an external viewer to display it.
-      if (this->content_received ())
-        {
-          this->deactivate (ACE_TRY_ENV);
-          ACE_TRY_CHECK;
-
-          (void) this->spawn_viewer ();
-        }
-    }
-  ACE_CATCHANY
-    {
-      ACE_PRINT_EXCEPTION (ACE_ANY_EXCEPTION,
-                           ACE_TEXT ("Caught unexpected exception ")
-                           ACE_TEXT ("in Callback_i::metdata(...):"));
-    }
-  ACE_ENDTRY;
-}
-
-int
-Callback_i::metadata_received (void)
-{
-  ACE_MT (ACE_GUARD_RETURN (ACE_SYNCH_MUTEX,
-                            guard,
-                            this->lock_,
-                            0));
-
-  return (this->metadata_.content_type.in () != 0);
-}
-
-int
-Callback_i::content_received (void)
-{
-  ACE_MT (ACE_GUARD_RETURN (ACE_SYNCH_MUTEX,
-                            guard,
-                            this->lock_,
-                            0));
-
-  return this->last_chunk_;
-}
-
-int
-Callback_i::get_viewer (char *viewer,
-                        size_t length)
-{
-  const char *content_type = 
-    this->metadata_.content_type.in ();
-
-  if (ACE_OS::strcasecmp (content_type, "text/html") == 0)
-    {
-      const char lynx[] = "lynx";
-      if (length <= sizeof (lynx))
-        return -1;
-      else
-        ACE_OS::strcpy (viewer, lynx);
-    }
-  else if (ACE_OS::strcasecmp (content_type,
-                               "text/plain") == 0)
-    {
-      const char more[] = "more";
-      if (length <= sizeof (more))
-        return -1;
-      else
-        ACE_OS::strcpy (viewer, more);
-    }
-  else if (ACE_OS::strcasecmp (content_type,
-                               "application/postscript") == 0)
-    {
-      const char ghostview[] = "ghostview";
-      if (length <= sizeof (ghostview))
-        return -1;
-      else
-        ACE_OS::strcpy (viewer, ghostview);
-    }
-  else if (ACE_OS::strcasecmp (content_type,
-                               "application/pdf") == 0)
-    {
-      const char acroread[] = "acroread";
-      if (length <= sizeof (acroread))
-        return -1;
-      else
-        ACE_OS::strcpy (viewer, acroread);
-    }
-  else if (ACE_OS::strcasecmp (content_type,
-                               "image/jpeg") == 0
-           || ACE_OS::strcasecmp (content_type,
-                                  "image/gif") == 0
-           || ACE_OS::strcasecmp (content_type,
-                                  "image/tiff") == 0
-           || ACE_OS::strcasecmp (content_type,
-                                  "image/png") == 0)
-    {
-      const char xv[] = "xv";
-      if (length <= sizeof (xv))
-        return -1;
-      else
-        ACE_OS::strcpy (viewer, xv);
-    }
-  else
-    ACE_ERROR_RETURN ((LM_ERROR,
-                       "Unsupported MIME type: <%s>\n",
-                       content_type),
-                      -1);
-
-  return 0;
-}
-
-int
-Callback_i::spawn_viewer (void)
-{
-  // It is highly unlikey, a mime type will ever be larger than 80
-  // bytes.
-  char viewer[80];
-
-  if (this->get_viewer (viewer,
-                        sizeof (viewer)) != 0)
-    ACE_ERROR_RETURN ((LM_ERROR,
-                       ACE_TEXT ("Problem determining which external ")
-                       ACE_TEXT ("viewer to use.\n")),
-                      -1);
-
-  // Set up the command line that will be used when spawning the
-  // external viewer.
-  ACE_Process_Options opts;
-  opts.command_line (ACE_TEXT ("%s %s"),
-                     viewer,
-                     this->file_.get_path_name ());
-
-  pid_t result = ACE_Process_Manager::instance ()->spawn (opts);
-
-  switch (result)
-    {
-    case 0:
-      // Child
-      return 0;
-    case ACE_INVALID_PID:
-      ACE_ERROR_RETURN ((LM_ERROR,
-                         ACE_TEXT ("%p\n"),
-                         ACE_TEXT ("Error during viewer spawn of ")
-                         ACE_TEXT ("\"%s\""),
-                         opts.command_line_buf ()),
-                        -1);
-    default:
-      // Parent
-      ACE_DEBUG ((LM_INFO,
-                  "Spawned viewer <%s> with PID <%d>.\n",
-                  viewer,
-                  result));
-      break;
-    }
-
-  return 0;
-}
-
-void
-Callback_i::deactivate (CORBA::Environment &ACE_TRY_ENV)
-{
-  // Get the POA used when activating the Reply Handler object.
-  PortableServer::POA_var poa = this->_default_POA (ACE_TRY_ENV);
-  ACE_CHECK;
-
-  // Get the object ID associated with this servant.
-  PortableServer::ObjectId_var oid =
-    poa->servant_to_id (this,
-                        ACE_TRY_ENV);
-  ACE_CHECK;
-
-  // Now deactivate the iterator object.
-  poa->deactivate_object (oid.in (), ACE_TRY_ENV);
-  ACE_CHECK;
-}
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback.h b/TAO/examples/Content_Server/AMI_Observer/Callback.h
deleted file mode 100644
index c6c230494f1..00000000000
--- a/TAO/examples/Content_Server/AMI_Observer/Callback.h
+++ /dev/null
@@ -1,108 +0,0 @@
-// -*- C++ -*-
-// $Id$
-
-// ============================================================================
-//
-// = LIBRARY
-//     Content_Server
-//
-// = FILENAME
-//     Callback.h
-//
-// = DESCRIPTION
-//     Header file for the Web_Server::Callback implementation.
-//
-// = AUTHOR
-//     Ossama Othman <ossama@uci.edu>
-//
-// ============================================================================
-
-#ifndef CALLBACK_H
-#define CALLBACK_H
-
-#include "ace/pre.h"
-
-#include "ace/FILE_Addr.h"
-#include "ace/FILE_IO.h"
-#include "Push_Web_ServerS.h"
-
-#if !defined (ACE_LACKS_PRAGMA_ONCE)
-# pragma once
-#endif /* ACE_LACKS_PRAGMA_ONCE */
-
-// Implement the Web_Server::Callback interface.
-class Callback_i :
-  public virtual POA_Web_Server::Callback,
-  public virtual PortableServer::RefCountServantBase
-{
-public:
-  Callback_i (int *request_count);
-  // Constructor
-
-  virtual void next_chunk (const Web_Server::Chunk_Type &chunk,
-                           CORBA::Boolean last_chunk,
-                           CORBA::Environment &ACE_TRY_ENV)
-    ACE_THROW_SPEC ((CORBA::SystemException));
-  // This operation returns the next <chunk> of the file starting at
-  // <offset>.  If there are no more bindings, false is returned.
-
-  void metadata (const Web_Server::Metadata_Type &metadata);
-  // Set metadata associated with received data.
-
-private:
-
-  ~Callback_i (void);
-  // Destructor must be private to ensure that this object is
-  // allocated on the heap.
-
-  int metadata_received (void);
-  // Returns one if the metadata was received, and zero otherwise.
-
-  int content_received (void);
-  // Returns one if the entire content was received, and zero
-  // otherwise.
-
-  int get_viewer (char *viewer, size_t length);
-  // Get the name of the viewer associated with the file being
-  // retrieved.
-
-  int spawn_viewer (void);
-  // Spawn an external view to display the retrieved file.
-
-private:
-
-  void deactivate (CORBA::Environment &ACE_TRY_ENV);
-  // Deactivate this Callback servant.
-
-private:
-
-  ACE_FILE_Addr file_;
-  // The Addr corresponding to the retrieved file.
-
-  ACE_FILE_IO file_io_;
-  // The object that provides all file related IO operations
-  // (e.g. read, write, etc).
-
-  Web_Server::AMI_CallbackHandler_var ami_handler_;
-  // Reference to this Reply Handler's self.
-
-  Web_Server::Metadata_Type metadata_;
-  // The metadata associated with the file being retrieved from the
-  // web server.
-
-  int last_chunk_;
-  // Flag that indicates entire data content has been received.
-
-  ACE_SYNCH_MUTEX lock_;
-  // Lock used to prevent race conditions when checking to see if
-  // metadata or entire content has been received.
-
-  int *request_count_;
-  // Pointer to external status monitoring variable. The contents (not
-  // the pointer itself) of the <pending_data> parameter will be
-  // decremented when file retrieval has completed.
-};
-
-#include "ace/post.h"
-
-#endif  /* CONTENT_ITERATOR_I_H */
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.cpp b/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.cpp
index 0172273b0d3..0ecfbdf5dbb 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.cpp
@@ -7,7 +7,7 @@
 #include "ace/Log_Msg.h"
 #include "Callback_Handler.h"
 
-ACE_RCSID(AMI_Observer, Callback_Handler, "$Id$")
+ACE_RCSID (AMI_Observer, Callback_Handler, "$Id$")
 
 Callback_Handler::Callback_Handler (const char *pathname,
                                     Web_Server::Callback_ptr client_callback)
@@ -43,6 +43,9 @@ Callback_Handler::next_chunk (CORBA::Environment &ACE_TRY_ENV)
   CORBA::Octet *buf =
     Web_Server::Chunk_Type::allocbuf (BUFSIZ);
 
+  if (buf == 0)
+    ACE_THROW (CORBA::NO_MEMORY ());
+
   ssize_t bytes_read = this->file_io_.recv (buf,
                                             BUFSIZ);
   if (bytes_read == -1)
@@ -82,7 +85,7 @@ Callback_Handler::next_chunk (CORBA::Environment &ACE_TRY_ENV)
 }
 
 void
-Callback_Handler::next_chunk_excep 
+Callback_Handler::next_chunk_excep
   (Web_Server::AMI_CallbackExceptionHolder *excep_holder,
    CORBA::Environment &)
   ACE_THROW_SPEC ((CORBA::SystemException))
@@ -107,26 +110,24 @@ Callback_Handler::next_chunk_excep
   ACE_ENDTRY;
 }
 
-ACE_HANDLE
+void
 Callback_Handler::run (CORBA::Environment &ACE_TRY_ENV)
   ACE_THROW_SPEC ((CORBA::SystemException,
                    Web_Server::Error_Result))
 {
   // Open the file to be downloaded
   this->open_file (ACE_TRY_ENV);
-  ACE_CHECK_RETURN (ACE_INVALID_HANDLE);
+  ACE_CHECK;
 
   // Activate this Reply Handler.
   this->ami_handler_ = this->_this (ACE_TRY_ENV);
-  ACE_CHECK_RETURN (ACE_INVALID_HANDLE);
+  ACE_CHECK;
 
   // Begin the asynchronous invocation.  Note that the AMI
   // "sendc_next_chunk()" call is done within the following call,
   // since data must first be read into the Chunk.
   this->next_chunk (ACE_TRY_ENV);
-  ACE_CHECK_RETURN (ACE_INVALID_HANDLE);
-
-  return this->file_io_.get_handle ();
+  ACE_CHECK;
 }
 
 void
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.h b/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.h
index 85686a24cee..5639ad94853 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.h
+++ b/TAO/examples/Content_Server/AMI_Observer/Callback_Handler.h
@@ -4,7 +4,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     Content_Server
+//     AMI_Observer
 //
 // = FILENAME
 //     Callback_Handler.h
@@ -35,6 +35,45 @@ class Callback_Handler
   : public virtual POA_Web_Server::AMI_CallbackHandler,
     public virtual PortableServer::RefCountServantBase
 {
+  // = TITLE
+  //    Class that asynchronously sends chunks of data to the
+  //    client-side <Callback> object, and handles all asynchronous
+  //    replies emanating from it.
+  //
+  // = DESCRIPTION
+  //    The <Push_Iterator_Factory_i> object in the Content Server
+  //    creates a <Callback_Handler> instance for each requested file,
+  //    and executes the run() method in that instance (in this
+  //    class).  To allow the Content Server to service other requests
+  //    without having to wait for the requested file to be completely
+  //    sent to the client, the run() method in this class issues the
+  //    next_chunk() method, which reads the first chunk of data and
+  //    sends it asynchronously to the client-side <Callback> object
+  //    by issuing a sendc_next_chunk() call.
+  //
+  //    This may seem a bit odd since the next_chunk() method in this
+  //    class is actually the reply handler method for the
+  //    sendc_next_chunk() method.  The next_chunk() method is
+  //    initially invoked as a means to bootstrap the process of
+  //    asynchronously sending chunks of data to the client-side
+  //    <Callback> object.  However, since the next_chunk() method
+  //    actually invokes sendc_next_chunk(), all subsequent calls will
+  //    be performed asynchronously.  This design also guarantees that
+  //    the client-side <Callback> object will receive all chunks of
+  //    data in the proper order since the next chunk of data will not
+  //    be sent until this <Callback_Handler> receives the asynchronous
+  //    reply from the client-side <Callback> object.  Again, that
+  //    asynchronous reply is handled by the next_chunk() method, at
+  //    which point the entire cycle is started again until the last
+  //    chunk of data is sent.
+  //
+  //    Notice that no threads are explicitly created at the
+  //    application level, yet concurrency is achieved due to the fact
+  //    that all operations are performed asynchronously.
+
+  friend class Callback_Handler_Friend;
+  // Dummy friend class declaration to quiet down a warning.
+
 public:
   Callback_Handler (const char *pathname,
                     Web_Server::Callback_ptr callback);
@@ -49,7 +88,7 @@ public:
                                  CORBA::Environment &)
     ACE_THROW_SPEC ((CORBA::SystemException));
 
-  ACE_HANDLE run (CORBA::Environment &ACE_TRY_ENV)
+  void run (CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException,
                      Web_Server::Error_Result));
   // Activate and run this Reply Handler.  The contents (not the
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback_i.cpp b/TAO/examples/Content_Server/AMI_Observer/Callback_i.cpp
index 6e473ea41ba..a0b0ac452ef 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Callback_i.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/Callback_i.cpp
@@ -7,9 +7,9 @@
 #include "ace/Log_Msg.h"
 #include "ace/Process_Manager.h"
 #include "ace/Synch.h"
-#include "Callback.h"
+#include "Callback_i.h"
 
-ACE_RCSID(AMI_Observer, Callback, "$Id$")
+ACE_RCSID (AMI_Observer, Callback_i, "$Id$")
 
 Callback_i::Callback_i (int *request_count)
   : file_ (ACE_sap_any_cast (ACE_FILE_Addr &)),
@@ -168,7 +168,7 @@ int
 Callback_i::get_viewer (char *viewer,
                         size_t length)
 {
-  const char *content_type = 
+  const char *content_type =
     this->metadata_.content_type.in ();
 
   if (ACE_OS::strcasecmp (content_type, "text/html") == 0)
@@ -223,7 +223,7 @@ Callback_i::get_viewer (char *viewer,
     }
   else
     ACE_ERROR_RETURN ((LM_ERROR,
-                       "Unsupported MIME type: <%s>\n",
+                       ACE_TEXT ("Unsupported MIME type: <%s>\n"),
                        content_type),
                       -1);
 
@@ -233,9 +233,7 @@ Callback_i::get_viewer (char *viewer,
 int
 Callback_i::spawn_viewer (void)
 {
-  // It is highly unlikey, a mime type will ever be larger than 80
-  // bytes.
-  char viewer[80];
+  char viewer[BUFSIZ];
 
   if (this->get_viewer (viewer,
                         sizeof (viewer)) != 0)
diff --git a/TAO/examples/Content_Server/AMI_Observer/Callback_i.h b/TAO/examples/Content_Server/AMI_Observer/Callback_i.h
index c6c230494f1..0faeccd12be 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Callback_i.h
+++ b/TAO/examples/Content_Server/AMI_Observer/Callback_i.h
@@ -4,10 +4,10 @@
 // ============================================================================
 //
 // = LIBRARY
-//     Content_Server
+//     AMI_Observer
 //
 // = FILENAME
-//     Callback.h
+//     Callback_i.h
 //
 // = DESCRIPTION
 //     Header file for the Web_Server::Callback implementation.
@@ -17,8 +17,8 @@
 //
 // ============================================================================
 
-#ifndef CALLBACK_H
-#define CALLBACK_H
+#ifndef CALLBACK_I_H
+#define CALLBACK_I_H
 
 #include "ace/pre.h"
 
@@ -35,6 +35,27 @@ class Callback_i :
   public virtual POA_Web_Server::Callback,
   public virtual PortableServer::RefCountServantBase
 {
+  // = TITLE
+  //    Implement the Web_Server::Callback interface.
+  //
+  // = DESCRIPTION
+  //    A <Callback> object implements the Observer pattern.  It
+  //    simply "watches" while the Content Server pushes chunks of
+  //    data to itself.  Once the Content Server pushes the last chunk
+  //    of data, the <Callback> object spawns an external viewer to
+  //    display the pushed data based on the data content type
+  //    returned by the Iterator_Factory::register_callback() method.
+  //
+  //    Since the server pushes data to the <Callback> object
+  //    asynchronously, and since instances of this <Callback> class
+  //    are registered with the Content Server asynchronously, there
+  //    is no guarantee that the metadata containing the content type
+  //    will arrive before the content of the file.  As such, this
+  //    class atomically sets and checks the flags that provide the
+  //    current condition of the metadata and content, in case two
+  //    concurrently running threads attempt to update the state
+  //    contained within a given <Callback> object.
+
 public:
   Callback_i (int *request_count);
   // Constructor
@@ -105,4 +126,4 @@ private:
 
 #include "ace/post.h"
 
-#endif  /* CONTENT_ITERATOR_I_H */
+#endif  /* CALLBACK_I_H */
diff --git a/TAO/examples/Content_Server/AMI_Observer/Makefile b/TAO/examples/Content_Server/AMI_Observer/Makefile
index d9c232c9488..b5c1359a201 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Makefile
+++ b/TAO/examples/Content_Server/AMI_Observer/Makefile
@@ -1,7 +1,6 @@
+#
 # $Id$
 #
-# Makefile for ECE 255 Web Server -- Assignment 4
-# Ossama Othman <ossama@uci.edu>
 
 
 #----------------------------------------------------------------------------
@@ -23,7 +22,7 @@ SERVER_FILES = \
 	server
 
 CLIENT_FILES = \
-	Callback \
+	Callback_i \
 	Push_Iterator_Handler \
 	client
 
@@ -1052,7 +1051,7 @@ realclean: clean
  $(ACE_ROOT)/ace/FILE.i \
  $(ACE_ROOT)/ace/FILE_IO.i
 
-.obj/Callback.o .obj/Callback.so .shobj/Callback.o .shobj/Callback.so: Callback.cpp \
+.obj/Callback_i.o .obj/Callback_i.so .shobj/Callback_i.o .shobj/Callback_i.so: Callback_i.cpp \
  $(ACE_ROOT)/ace/FILE_Connector.h \
  $(ACE_ROOT)/ace/pre.h \
  $(ACE_ROOT)/ace/FILE_IO.h \
@@ -1152,8 +1151,8 @@ realclean: clean
  $(ACE_ROOT)/ace/Reactor_Impl.h \
  $(ACE_ROOT)/ace/Process.h \
  $(ACE_ROOT)/ace/Process.i \
- $(ACE_ROOT)/ace/Process_Manager.i Callback.h \
- Push_Web_ServerS.h \
+ $(ACE_ROOT)/ace/Process_Manager.i \
+ Callback_i.h Push_Web_ServerS.h \
  $(TAO_ROOT)/tao/MessagingS.h \
  $(TAO_ROOT)/tao/orbconf.h \
  $(TAO_ROOT)/tao/TimeBaseS.h \
@@ -1694,7 +1693,7 @@ realclean: clean
  $(TAO_ROOT)/tao/BoundsC.h \
  $(TAO_ROOT)/tao/BoundsC.i \
  Push_Web_ServerC.i Push_Web_ServerS_T.h Push_Web_ServerS_T.i \
- Push_Web_ServerS_T.cpp Push_Web_ServerS.i Callback.h \
+ Push_Web_ServerS_T.cpp Push_Web_ServerS.i Callback_i.h \
  $(ACE_ROOT)/ace/FILE_Addr.h \
  $(ACE_ROOT)/ace/Addr.h \
  $(ACE_ROOT)/ace/Addr.i \
diff --git a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.cpp b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.cpp
index 1667618cf4d..73ef258aea8 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.cpp
@@ -6,10 +6,10 @@
 #include "Push_Iterator_Factory_i.h"
 #include "Callback_Handler.h"
 
-ACE_RCSID(AMI_Observer, Push_Iterator_Factory_i, "$Id$")
+ACE_RCSID (AMI_Observer, Push_Iterator_Factory_i, "$Id$")
 
 Web_Server::Metadata_Type *
-Push_Iterator_Factory_i::register_callback 
+Push_Iterator_Factory_i::register_callback
   (const char *pathname,
    Web_Server::Callback_ptr client_callback,
    CORBA::Environment &ACE_TRY_ENV)
@@ -27,7 +27,7 @@ Push_Iterator_Factory_i::register_callback
   // content.
 
   ACE_DEBUG ((LM_DEBUG,
-              "Received request for file: <%s>\n",
+              ACE_TEXT ("Received request for file: <%s>\n"),
               pathname));
 
   // Send the file to the client asynchronously.  This allows the
@@ -42,34 +42,42 @@ Push_Iterator_Factory_i::register_callback
   // Transfer ownership to the POA.
   PortableServer::ServantBase_var tmp (handler);
 
-  ACE_HANDLE fd = handler->run (ACE_TRY_ENV);
+  // Start sending data to the client callback object.
+  handler->run (ACE_TRY_ENV);
   ACE_CHECK_RETURN (0);
 
   struct stat file_status;
-  if (fd == ACE_INVALID_HANDLE
-      || ACE_OS::fstat (fd,
-                        &file_status) == -1)
+  if (ACE_OS::stat (pathname,
+                    &file_status) == -1)
     // HTTP 1.1 "Internal Server Error".
     ACE_THROW_RETURN (Web_Server::Error_Result (500),
                       0);
-  Web_Server::Metadata_Type_var metadata =
-    new Web_Server::Metadata_Type;
+
+  Web_Server::Metadata_Type *meta_tmp = 0;
+  ACE_NEW_THROW_EX (meta_tmp,
+                    Web_Server::Metadata_Type,
+                    CORBA::NO_MEMORY ());
+  ACE_CHECK_RETURN (0);
+
+  Web_Server::Metadata_Type_var metadata = meta_tmp;
 
   if (this->modification_date (&file_status,
                                metadata.inout ()) != 0)
     // HTTP 1.1 "Internal Server Error.
     ACE_THROW_RETURN (Web_Server::Error_Result (500),
                       0);
+
   if (this->content_type (pathname,
                           metadata.inout ()) != 0)
     // HTTP 1.1 "Internal Server Error.
     ACE_THROW_RETURN (Web_Server::Error_Result (500),
                       0);
+
   return metadata._retn ();
 }
 
 int
-Push_Iterator_Factory_i::modification_date 
+Push_Iterator_Factory_i::modification_date
   (struct stat *file_status,
    Web_Server::Metadata_Type & metadata)
 {
@@ -154,9 +162,9 @@ Push_Iterator_Factory_i::content_type (const char *filename,
     {
       metadata.content_type = CORBA::string_dup ("text/html");
       ACE_ERROR ((LM_WARNING,
-                  "\n  "
-                  "Unknown file type.  "
-                  "Using \"text/html\" content type.\n"));
+                  ACE_TEXT ("\n  ")
+                  ACE_TEXT ("Unknown file type.  ")
+                  ACE_TEXT ("Using \"text/html\" content type.\n")));
     }
 
   return 0;
diff --git a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.h b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.h
index d6a51ad2e9d..aba6d9e3535 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.h
+++ b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Factory_i.h
@@ -5,7 +5,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     Content_Server
+//     AMI_Observer
 //
 // = FILENAME
 //     Push_Iterator_Factory_i.h
@@ -35,9 +35,22 @@ class Push_Iterator_Factory_i :
   virtual public POA_Web_Server::Iterator_Factory
 {
   // = TITLE
-  // Implement the Web_Server::Iterator_Factory interface.
+  //    Implement the Web_Server::Iterator_Factory interface.
+  //
+  // = DESCRIPTION
+  //    This class is used to register a client-side <Callback> object
+  //    with the Content Server, which is actually implemented by the
+  //    <Callback_Handler> class for each requested file.
+  //
+  //    The client invokes the register_callback() method in this
+  //    class.  That method then creates a <Callback_Handler> which
+  //    will push chunks of data asynchronously to the client-side
+  //    <Callback> object.  This allows the Content Server to
+  //    concurrently service multiple file requests without the need
+  //    to explicitly use threads at the application level.
+
 public:
-  Web_Server::Metadata_Type *register_callback 
+  Web_Server::Metadata_Type *register_callback
     (const char *pathname,
      Web_Server::Callback_ptr client_callback,
      CORBA::Environment &ACE_TRY_ENV)
diff --git a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.cpp b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.cpp
index 778cf94d274..4cf2a709de5 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.cpp
@@ -6,9 +6,9 @@
 #include "ace/Log_Msg.h"
 #include "ace/Process_Manager.h"
 #include "Push_Iterator_Handler.h"
-#include "Callback.h"
+#include "Callback_i.h"
 
-ACE_RCSID(AMI_Observer, Push_Iterator_Handler, "$Id$")
+ACE_RCSID (AMI_Observer, Push_Iterator_Handler, "$Id$")
 
 Push_Iterator_Handler::Push_Iterator_Handler (void)
   : callback_servant_ (0),
@@ -24,7 +24,7 @@ Push_Iterator_Handler::~Push_Iterator_Handler (void)
 }
 
 void
-Push_Iterator_Handler::register_callback 
+Push_Iterator_Handler::register_callback
   (const Web_Server::Metadata_Type &metadata,
    CORBA::Environment &ACE_TRY_ENV)
   ACE_THROW_SPEC ((CORBA::SystemException))
diff --git a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.h b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.h
index bae26e065f0..87eb65fafe7 100644
--- a/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.h
+++ b/TAO/examples/Content_Server/AMI_Observer/Push_Iterator_Handler.h
@@ -1,12 +1,10 @@
 // -*- C++ -*-
 // $Id$
 
-// Ossama Othman <ossama@uci.edu>
-
 // ============================================================================
 //
 // = LIBRARY
-//     ECE255
+//     AMI_Observer
 //
 // = FILENAME
 //     Push_Iterator_Handler.h
@@ -37,6 +35,29 @@ class Push_Iterator_Handler
   : public virtual POA_Web_Server::AMI_Iterator_FactoryHandler,
     public virtual PortableServer::RefCountServantBase
 {
+  // = TITLE
+  //    Implement the Web_Server::Iterator_Factory AMI Reply Handler.
+  //
+  // = DESCRIPTION
+  //    This classes asynchronously registers a reference to the
+  //    client-side <Callback> object in the Content Server.  Once
+  //    registered, the <Callback> will begin receiving chunks of data
+  //    pushed from the Content Server.
+  //
+  //    Since registration occurs asynchronously, it is possible that
+  //    the metadata returned from the <Iterator_Factory> will be
+  //    received after the content of the file has been received.  The
+  //    <Callback> object is equipped to handle this possibility.
+  //
+  //    The register_callback() reply handler method in this class
+  //    receives the metadata, and then passes it to the <Callback>
+  //    object.  Once the metadata is received, there is no longer any
+  //    use for this <Push_Iterator_Handler> object, and it is
+  //    deactivated.
+
+  friend class Push_Iterator_Handler_Friend;
+  // Dummy friend class declaration to quiet down a warning.
+
 public:
   Push_Iterator_Handler (void);
   // Constructor that creates a content iterator corresponding to the
@@ -66,7 +87,7 @@ private:
   // AMI callback that is invoked when a response from the
   // corresponding server method is received.
 
-  virtual void register_callback_excep 
+  virtual void register_callback_excep
   (Web_Server::AMI_Iterator_FactoryExceptionHolder *,
    CORBA::Environment &)
     ACE_THROW_SPEC ((CORBA::SystemException)) {}
diff --git a/TAO/examples/Content_Server/AMI_Observer/README b/TAO/examples/Content_Server/AMI_Observer/README
index 8c5d635dcb2..f9e4de33b5d 100644
--- a/TAO/examples/Content_Server/AMI_Observer/README
+++ b/TAO/examples/Content_Server/AMI_Observer/README
@@ -14,7 +14,66 @@ is as follows:
 
         * The CORBA Naming Service is used to bind and resolve object
           references, rather than using a file.
-    
+
+
+Basic design of the programs:
+
+The basic idea used in both the client and and the server is to use
+AMI when performing all requests.  This allows both the client and the
+server to perform other tasks without having to wait for a given task
+to complete.
+
+The client first activates its Callback object, and then
+asynchronously registers a reference to its Callback object with the
+server's Push_Iterator_Factory.  The Push_Iterator_Factory then
+creates an AMI reply handler "Callback_Handler" for the requested file
+that asynchronously sends chunks of data to the client's Callback
+object.  After creating and running the Callback_Handler, the
+Push_Iterator_Factory returns the Metadata containing the content type
+and modification date of the file to client.  Since the Callback was
+registered using the Push_Iterator_Factory using AMI, an AMI reply
+handler called "Push_Iterator_Handler" on the client side will receive
+and handle the Metadata returned from the Push_Iterator_Factory.  The
+Push_Iterator_Handler then passes the received Metadata to the
+Callback object.  The Callback will spawn an external viewer once both
+the Metadata and the entire file content have been received.  The
+Callback object is designed to correctly handle the case where the
+content is received before the Metadata, and vice versa.  This
+operation is thread-safe.  Note that no threads are created at the
+application level in neither the client nor the server, yet
+concurrency is still achieved due to the fact that AMI is used on both
+sides.
+
+A schematic of the operations involved follows:
+
+  CLIENT				SERVER
+  ------				------
+  Push_Iterator_Handler - activate
+  Callback - activate			Push_Iterator_Factory - activate
+
+  sendc_register_callback()	--->	register_callback()
+					Callback_Handler - activate
+
+  next_chunk()			<---	sendc_next_chunk()
+  .					.
+  .					.
+  .					.
+  next_chunk()			<---	sendc_next_chunk()
+
+  register_callback()		<---	Metadata - returned
+  Metadata passed to Callback
+
+  next_chunk()			<---	sendc_next_chunk()
+  .					.
+  .					.
+  .					.
+  next_chunk()			<---	sendc_next_chunk()
+
+Note that the Callback_Handler will not send the next chunk until it
+receives a reply from the client's Callback object.  This ensures that
+the client receives all chunks of data in the proper order.
+
+
 The client program performs the following activities:
           
         1. From the command-line, it reads the name of the pathname
@@ -25,10 +84,10 @@ The client program performs the following activities:
            object reference for a CosNaming::NamingContext interface,
            which is then used to resolve the object reference that the
            server bound earlier.  After narrowing this to the Server
-           interface, the register_callback() operation is called via
-           the object reference to pass the Callback interface from
-           the client to the server, which then uses AMI to push
-           chunks of the file to the client.
+           interface, the sendc_register_callback() operation is
+           called via the object reference to pass asynchronously pass
+           the Callback interface from the client to the server, which
+           then uses AMI to push chunks of the file to the client.
           
         2. The server calls the sendc_next_chunk() method on the
            callback, passing in the offset and the next chunk.  
@@ -40,6 +99,7 @@ The client program performs the following activities:
            viewer is spawned to display the file.  The type of viewer
            to spawn is determined by examining the the content_type_
            metadata returned by the server.
+	
        
 The example can be run as follows:
 
diff --git a/TAO/examples/Content_Server/AMI_Observer/client.cpp b/TAO/examples/Content_Server/AMI_Observer/client.cpp
index 53cfc089aeb..f81d307bc7f 100644
--- a/TAO/examples/Content_Server/AMI_Observer/client.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/client.cpp
@@ -8,7 +8,19 @@
 #include "Push_Web_ServerC.h"
 #include "Push_Iterator_Handler.h"
 
-ACE_RCSID(AMI_Observer, client, "$Id$")
+ACE_RCSID (AMI_Observer, client, "$Id$")
+
+// Obtain reference to Iterator_Factory
+Web_Server::Iterator_Factory_ptr
+get_iterator (CORBA::ORB_ptr orb,
+              CORBA::Environment &ACE_TRY_ENV);
+
+// Perform file requests
+void invoke_requests (int argc,
+                      char *argv[],
+                      int *request_count,
+                      Web_Server::Iterator_Factory_ptr f,
+                      CORBA::Environment &ACE_TRY_ENV);
 
 int
 main (int argc, char *argv[])
@@ -18,7 +30,8 @@ main (int argc, char *argv[])
     {
       if (argc < 2)
         ACE_ERROR_RETURN ((LM_ERROR,
-                           "Usage: client filename [filename ...]\n"),
+                           ACE_TEXT ("Usage: client filename ")
+                           ACE_TEXT ("[filename ...]\n")),
                           -1);
 
       // Initialize the ORB.
@@ -43,40 +56,18 @@ main (int argc, char *argv[])
       mgr->activate (ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
-      // Get a reference to the Name Service.
-      obj = orb->resolve_initial_references ("NameService",
-                                             ACE_TRY_ENV);
-      ACE_TRY_CHECK;
-
-      // Narrow to a Naming Context
-      CosNaming::NamingContext_var nc = 
-        CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
-      ACE_TRY_CHECK;
-
-      if (CORBA::is_nil (obj.in ()))
-        {
-          ACE_ERROR_RETURN ((LM_ERROR,
-                             "Nil reference to Name Service\n"),
-                            -1);
-        }
-
-      // Create a name.
-      CosNaming::Name name;
-      name.length (1);
-      name[0].id = CORBA::string_dup ("Push_Iterator_Factory");
-      name[0].kind = CORBA::string_dup ("");
-
-      obj = nc->resolve (name, ACE_TRY_ENV);
+      // Get an Iterator_Factory reference.
+      Web_Server::Iterator_Factory_var factory =
+        ::get_iterator (orb.in (),
+                        ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
-      // Now narrow to an Iterator_Factory reference.
-      Web_Server::Iterator_Factory_var factory =
-        Web_Server::Iterator_Factory::_narrow (obj.in ());
       if (CORBA::is_nil (factory.in ()))
         {
           ACE_ERROR_RETURN ((LM_ERROR,
-                             "Object pointed to by:\n  %s\n"
-                             "is not an Iterator_Factory object.\n",
+                             ACE_TEXT ("Object pointed to by:\n %s\n")
+                             ACE_TEXT ("is not an Iterator_Factory")
+                             ACE_TEXT ("object.\n"),
                              argv[1]),
                             -1);
         }
@@ -86,24 +77,12 @@ main (int argc, char *argv[])
       int request_count = 0;
 
       // Activate and run the reply handlers.
-      for (int i = 0;
-           i < argc - 1;  // Don't include the program name.
-           ++i)
-        {
-          Push_Iterator_Handler *handler = 0;
-          ACE_NEW_RETURN (handler,
-                          Push_Iterator_Handler,
-                          -1);
-
-          // Transfer ownership to the POA.
-          PortableServer::ServantBase_var tmp_handler (handler);
-
-          handler->run (&request_count,
-                        argv[i + 1],
-                        factory.in (),
-                        ACE_TRY_ENV);
-          ACE_TRY_CHECK;
-        }
+      ::invoke_requests (argc,
+                         argv,
+                         &request_count,
+                         factory.in (),
+                         ACE_TRY_ENV);
+      ACE_TRY_CHECK;
 
       // 1 millisecond delay to reduce "busy waiting" in ORB event
       // loop.
@@ -131,14 +110,15 @@ main (int argc, char *argv[])
   ACE_CATCH (Web_Server::Error_Result, exc)
     {
       ACE_ERROR_RETURN ((LM_ERROR,
-                         "Caught Web Server exception with status %d\n",
+                         ACE_TEXT ("Caught Web Server exception ")
+                         ACE_TEXT ("status %d\n"),
                          exc.status),
                         -1);
     }
   ACE_CATCHANY
     {
       ACE_PRINT_EXCEPTION (ACE_ANY_EXCEPTION,
-                           "Caught unexpected exception:");
+                           ACE_TEXT ("Caught unexpected exception:"));
 
       return -1;
     }
@@ -149,3 +129,74 @@ main (int argc, char *argv[])
 
   return 0;
 }
+
+Web_Server::Iterator_Factory_ptr
+get_iterator (CORBA::ORB_ptr o,
+              CORBA::Environment &ACE_TRY_ENV)
+{
+  CORBA::ORB_var orb = CORBA::ORB::_duplicate (o);
+
+  // Get a reference to the Name Service.
+  CORBA::Object_var obj =
+    orb->resolve_initial_references ("NameService",
+                                     ACE_TRY_ENV);
+  ACE_CHECK_RETURN (Web_Server::Iterator_Factory::_nil ());
+
+  // Narrow to a Naming Context
+  CosNaming::NamingContext_var nc =
+    CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
+  ACE_CHECK_RETURN (Web_Server::Iterator_Factory::_nil ());
+
+  if (CORBA::is_nil (obj.in ()))
+    {
+      ACE_ERROR ((LM_ERROR,
+                  ACE_TEXT ("Nil reference to Name Service\n")));
+      return Web_Server::Iterator_Factory::_nil ();
+    }
+
+  // Create a name.
+  CosNaming::Name name;
+  name.length (1);
+  name[0].id = CORBA::string_dup ("Push_Iterator_Factory");
+  name[0].kind = CORBA::string_dup ("");
+
+  obj = nc->resolve (name, ACE_TRY_ENV);
+  ACE_CHECK_RETURN (Web_Server::Iterator_Factory::_nil ());
+
+  Web_Server::Iterator_Factory_ptr factory =
+    Web_Server::Iterator_Factory::_narrow (obj.in ());
+
+  return factory;
+}
+
+void invoke_requests (int argc,
+                      char *argv[],
+                      int *request_count,
+                      Web_Server::Iterator_Factory_ptr f,
+                      CORBA::Environment &ACE_TRY_ENV)
+{
+  Web_Server::Iterator_Factory_var factory =
+    Web_Server::Iterator_Factory::_duplicate (f);
+
+  // Activate and run the reply handlers.
+  for (int i = 0;
+       i < argc - 1;  // Don't include the program name.
+       ++i)
+    {
+      Push_Iterator_Handler *handler = 0;
+      ACE_NEW_THROW_EX (handler,
+                        Push_Iterator_Handler,
+                        CORBA::NO_MEMORY ());
+      ACE_CHECK;
+
+      // Transfer ownership to the POA.
+      PortableServer::ServantBase_var tmp (handler);
+
+      // This ends up being an AMI call, so it won't block.
+      handler->run (request_count,
+                    argv[i + 1],
+                    factory.in (),
+                    ACE_TRY_ENV);
+      ACE_CHECK;
+    }
+}
diff --git a/TAO/examples/Content_Server/AMI_Observer/server.cpp b/TAO/examples/Content_Server/AMI_Observer/server.cpp
index 5fa713faf6e..501b2db71d9 100644
--- a/TAO/examples/Content_Server/AMI_Observer/server.cpp
+++ b/TAO/examples/Content_Server/AMI_Observer/server.cpp
@@ -7,7 +7,7 @@
 #include "Push_Web_ServerS.h"
 #include "Push_Iterator_Factory_i.h"
 
-ACE_RCSID(AMI_Observer, server, "$Id$")
+ACE_RCSID (AMI_Observer, server, "$Id$")
 
 int
 main (int argc, char *argv[])
@@ -49,7 +49,7 @@ main (int argc, char *argv[])
       ACE_TRY_CHECK;
 
       // Narrow to a Naming Context
-      CosNaming::NamingContext_var nc = 
+      CosNaming::NamingContext_var nc =
         CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
@@ -67,12 +67,12 @@ main (int argc, char *argv[])
                                                      ACE_TRY_ENV);
       ACE_TRY_CHECK;
       ACE_DEBUG ((LM_DEBUG,
-                  "Bound <%s> to <%s> in Name Service.\n",
+                  ACE_TEXT ("Bound <%s> to <%s> in Name Service.\n"),
                   name[0].id.in (),
                   IOR.in ()));
 
       ACE_DEBUG ((LM_INFO,
-                  "Accepting requests.\n"));
+                  ACE_TEXT ("Accepting requests.\n")));
 
       // Accept requests.
       orb->run (ACE_TRY_ENV);
@@ -81,7 +81,7 @@ main (int argc, char *argv[])
   ACE_CATCHANY
     {
       ACE_PRINT_EXCEPTION (ACE_ANY_EXCEPTION,
-                           "Caught unexpected exception:");
+                           ACE_TEXT ("Caught unexpected exception:"));
 
       return -1;
     }
diff --git a/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.cpp b/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.cpp
index e82359ff97a..428cf5cee73 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.cpp
+++ b/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.cpp
@@ -27,11 +27,17 @@ Content_Iterator_i::~Content_Iterator_i (void)
 CORBA::Boolean
 Content_Iterator_i::next_chunk (CORBA::ULong offset,
                                 Web_Server::Chunk_Type_out chunk,
-                                CORBA::Environment &)
+                                CORBA::Environment &ACE_TRY_ENV)
   ACE_THROW_SPEC ((CORBA::SystemException))
 {
   // Initialize/allocate the Chunk_Type sequence
-  chunk = new Web_Server::Chunk_Type;
+  Web_Server::Chunk_Type *tmp = 0;
+  ACE_NEW_THROW_EX (tmp,
+                    Web_Server::Chunk_Type,
+                    CORBA::NO_MEMORY ());
+  ACE_CHECK_RETURN (0);
+
+  chunk = tmp;
 
   if (offset >= this->file_size_)
     return 0;  // Applications shouldn't throw system exceptions.
diff --git a/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.h b/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.h
index 2295cbb59f7..72e418dfab5 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.h
+++ b/TAO/examples/Content_Server/SMI_Iterator/Content_Iterator_i.h
@@ -5,7 +5,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     ECE255
+//     SMI_ITERATOR
 //
 // = FILENAME
 //     Content_Iterator_i.h
@@ -29,30 +29,39 @@
 # pragma once
 #endif /* ACE_LACKS_PRAGMA_ONCE */
 
-// Implement the Web_Server::Content_Iterator interface.
 class Content_Iterator_i :
   public virtual POA_Web_Server::Content_Iterator,
   public virtual PortableServer::RefCountServantBase
 {
+  // = TITLE
+  //    Implement the Web_Server::Content_Iterator interface.
+  //
+  // = DESCRIPTION
+  //    This class implements the Iterator pattern to minimize memory
+  //    requirements when retrieving data from a content server.
+  //    Rather than retrieving one large chunk of data, this class
+  //    iterates on the server so that smaller chunks of data are
+  //    retrieved.
+
   friend class Iterator_Factory_i;
 public:
 
-  // Constructor
   Content_Iterator_i (const char *filename, CORBA::ULong file_size);
+  // Constructor
 
-  // Destructor
   ~Content_Iterator_i (void);
+  // Destructor
 
-  // This operation returns the next <chunk> of the file starting at
-  // <offset>.  If there are no more bindings, false is returned.
   virtual CORBA::Boolean next_chunk (CORBA::ULong offset,
                                      Web_Server::Chunk_Type_out chunk,
                                      CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException));
+  // This operation returns the next <chunk> of the file starting at
+  // <offset>.  If there are no more bindings, false is returned.
 
-  // Destroy the iterator.
   virtual void destroy (CORBA::Environment &ACE_TRY_ENV)
     ACE_THROW_SPEC ((CORBA::SystemException));
+  // Destroy the iterator.
 
 private:
 
@@ -75,7 +84,4 @@ private:
   // for debugging purposes.)
 };
 
-
-
-
 #endif  /* CONTENT_ITERATOR_I_H */
diff --git a/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.cpp b/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.cpp
index 3adf63f4e66..ad0e0cad479 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.cpp
+++ b/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.cpp
@@ -6,7 +6,7 @@
 #include "Content_Iterator_i.h"
 #include "Iterator_Factory_i.h"
 
-ACE_RCSID(SMI_Iterator, Iterator_Factory_i, "$Id$")
+ACE_RCSID (SMI_Iterator, Iterator_Factory_i, "$Id$")
 
 void
 Iterator_Factory_i::get_iterator (const char *pathname,
@@ -15,8 +15,6 @@ Iterator_Factory_i::get_iterator (const char *pathname,
                                   CORBA::Environment &ACE_TRY_ENV)
   ACE_THROW_SPEC ((CORBA::SystemException, Web_Server::Error_Result))
 {
-  // Based on code available in H&V.
-
   ACE_DEBUG ((LM_DEBUG,
               ACE_TEXT ("Received request for file: <%s>\n"),
               pathname));
@@ -55,7 +53,13 @@ Iterator_Factory_i::get_iterator (const char *pathname,
     iterator_servant->_this (ACE_TRY_ENV);
   ACE_CHECK;
 
-  metadata = new Web_Server::Metadata_Type;
+  Web_Server::Metadata_Type *tmp = 0;
+  ACE_NEW_THROW_EX (tmp,
+                    Web_Server::Metadata_Type,
+                    CORBA::NO_MEMORY ());
+  ACE_CHECK;
+
+  metadata = tmp;
 
   if (this->modification_date (&file_status,
                                metadata) != 0)
diff --git a/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.h b/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.h
index c78465eabd3..beb2f5c1866 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.h
+++ b/TAO/examples/Content_Server/SMI_Iterator/Iterator_Factory_i.h
@@ -5,7 +5,7 @@
 // ============================================================================
 //
 // = LIBRARY
-//     ECE255
+//     SMI_ITERATOR
 //
 // = FILENAME
 //     Iterator_Factory_i.h
@@ -32,29 +32,38 @@
 struct stat;
 class Content_Iterator_i;
 
-// Implement the Web_Server::Iterator_Factory interface.
 class Iterator_Factory_i : virtual public POA_Web_Server::Iterator_Factory
 {
+  // = TITLE
+  //    Factory that creates a Content_Iterator that retrieves fixed
+  //    size chunks of data from Content server.
+  //
+  // = DESCRIPTION
+  //    This class creates a Content_Iterator that is set up to
+  //    iteratively download a specific file.  This same factory can
+  //    be used to create Content_Iterators for other files.
+
 public:
 
-  // This factory method returns a <Content_Iterator> that can be used
-  // to read the <contents> associated with <pathname> one ``chunk''
-  // at a time.  The <metadata> reports information about the
-  // <contents>.
   virtual void get_iterator (const char *pathname,
                              Web_Server::Content_Iterator_out contents,
                              Web_Server::Metadata_Type_out metadata,
-                             CORBA::Environment &ACE_TRY_ENV)
+                             CORBA::Environment &ACE_TRY_ENV =
+                               TAO_default_environment ())
     ACE_THROW_SPEC ((CORBA::SystemException,
                      Web_Server::Error_Result));
+  // This factory method returns a <Content_Iterator> that can be used
+  // to read the <contents> associated with <pathname> one ``chunk''
+  // at a time.  The <metadata> reports information about the
+  // <contents>.
 
-  // Set the file modification date in the metadata structure.
   int modification_date (struct stat *file_status,
                          Web_Server::Metadata_Type_out metadata);
+  // Set the file modification date in the metadata structure.
 
-  // Set the type of file content in the metadata structure.
   int content_type (const char *filename,
                     Web_Server::Metadata_Type_out metadata);
+  // Set the type of file content in the metadata structure.
 
 };
 
diff --git a/TAO/examples/Content_Server/SMI_Iterator/Web_Server.idl b/TAO/examples/Content_Server/SMI_Iterator/Web_Server.idl
index 055f8159476..47838ae6d3b 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/Web_Server.idl
+++ b/TAO/examples/Content_Server/SMI_Iterator/Web_Server.idl
@@ -7,14 +7,14 @@ module Web_Server
 
   interface Content_Iterator
   {
+    boolean next_chunk (in unsigned long offset,
+                        out Chunk_Type chunk);
     // This operation returns the next <chunk> of the
     // file starting at <offset>.  If there are
     // no more bindings, false is returned.
-    boolean next_chunk (in unsigned long offset,
-                        out Chunk_Type chunk);
 
-    // This operation destroys the iterator.
     void destroy ();
+    // This operation destroys the iterator.
   };
 
   exception Error_Result {
@@ -27,22 +27,22 @@ module Web_Server
 
   struct Metadata_Type
   {
-    // Modification date.
     string modification_date;
-    
-    // Type of content.
+    // Modification date.
+
     string content_type;
+    // Type of content.
   };
 
   interface Iterator_Factory
   {
-    // This factory method returns a <Content_Iterator> that
-    // can be used to read the <contents> associated with
-    // <pathname> one ``chunk'' at a time.  The <metadata>
-    // reports information about the <contents>. 
     void get_iterator (in string pathname,
                        out Content_Iterator contents,
                        out Metadata_Type metadata)
       raises (Error_Result);
+    // This factory method returns a <Content_Iterator> that
+    // can be used to read the <contents> associated with
+    // <pathname> one ``chunk'' at a time.  The <metadata>
+    // reports information about the <contents>.
   };
 };
diff --git a/TAO/examples/Content_Server/SMI_Iterator/client.cpp b/TAO/examples/Content_Server/SMI_Iterator/client.cpp
index 19c9343132a..bad90986181 100644
--- a/TAO/examples/Content_Server/SMI_Iterator/client.cpp
+++ b/TAO/examples/Content_Server/SMI_Iterator/client.cpp
@@ -34,7 +34,7 @@ main (int argc, char *argv[])
     {
       if (argc < 2)
         ACE_ERROR_RETURN ((LM_ERROR,
-                           "Usage: client filename\n"),
+                           ACE_TEXT ("Usage: client filename\n")),
                           -1);
 
       // Initialize the ORB.
@@ -51,8 +51,8 @@ main (int argc, char *argv[])
       ACE_TRY_CHECK;
 
       // Narrow to a Naming Context
-      CosNaming::NamingContext_var nc;
-      nc = CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
+      CosNaming::NamingContext_var nc =
+        CosNaming::NamingContext::_narrow (obj.in (), ACE_TRY_ENV);
       ACE_TRY_CHECK;
 
       if (CORBA::is_nil (obj.in ()))