#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.2).
# To extract the files from this archive, save it to some FILE, remove
# everything before the `!/bin/sh' line above, then type `sh FILE'.
#
# Made on 2000-03-19 15:00 EST by <jcej@chiroptera.tragus.org>.
# Source directory was `/home/jcej/projects/ACE_wrappers/docs/tutorials/006'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode name
# ------ ---------- ------------------------------------------
# 605 -rw-rw-r-- hdr
# 72 -rw-rw-r-- bodies
# 1971 -rw-rw-r-- page01.pre
# 252 -rw-rw-r-- page02.pre
# 507 -rw-rw-r-- page03.pre
# 227 -rw-rw-r-- page04.pre
# 225 -rw-rw-r-- page05.pre
# 697 -rw-rw-r-- page06.pre
# 89 -rw-rw-r-- page02.pst
# 168 -rw-rw-r-- page03.pst
# 175 -rw-rw-r-- page04.pst
# 1418 -rw-rw-r-- page05.pst
#
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=FAILED
locale_dir=FAILED
first_param="$1"
for dir in $PATH
do
if test "$gettext_dir" = FAILED && test -f $dir/gettext \
&& ($dir/gettext --version >/dev/null 2>&1)
then
set `$dir/gettext --version 2>&1`
if test "$3" = GNU
then
gettext_dir=$dir
fi
fi
if test "$locale_dir" = FAILED && test -f $dir/shar \
&& ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
then
locale_dir=`$dir/shar --print-text-domain-dir`
fi
done
IFS="$save_IFS"
if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
then
echo=echo
else
TEXTDOMAINDIR=$locale_dir
export TEXTDOMAINDIR
TEXTDOMAIN=sharutils
export TEXTDOMAIN
echo="$gettext_dir/gettext -s"
fi
touch -am 1231235999 $$.touch >/dev/null 2>&1
if test ! -f 1231235999 && test -f $$.touch; then
shar_touch=touch
else
shar_touch=:
echo
$echo 'WARNING: not restoring timestamps. Consider getting and'
$echo "installing GNU \`touch', distributed in GNU File Utilities..."
echo
fi
rm -f 1231235999 $$.touch
#
if mkdir _sh32413; then
$echo 'x -' 'creating lock directory'
else
$echo 'failed to create lock directory'
exit 1
fi
# ============= hdr ==============
if test -f 'hdr' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'hdr' '(file already exists)'
else
$echo 'x -' extracting 'hdr' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'hdr' &&
<HTML>
<HEAD>
X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
X <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (X11; I; Linux 2.0.32 i486) [Netscape]">
X <META NAME="Author" CONTENT="James CE Johnson">
X <META NAME="Description" CONTENT="A first step towards using ACE productively">
X <TITLE>ACE Tutorial 006</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
X
<CENTER><B><FONT SIZE=+2>ACE Tutorial 006</FONT></B></CENTER>
X
<CENTER><B><FONT SIZE=+2>Creating a thread-per-connection server</FONT></B></CENTER>
X
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 03191459100 'hdr' &&
chmod 0664 'hdr' ||
$echo 'restore of' 'hdr' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'hdr:' 'MD5 check failed'
3289bf210fdf2f4b9d0a23b69c79a82f hdr
SHAR_EOF
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$echo 'hdr:' 'original size' '605,' 'current size' "$shar_count!"
fi
fi
# ============= bodies ==============
if test -f 'bodies' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'bodies' '(file already exists)'
else
$echo 'x -' extracting 'bodies' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'bodies' &&
PAGE=2
server.cpp
client_acceptor.h
client_handler.h
client_handler.cpp
SHAR_EOF
$shar_touch -am 0118202399 'bodies' &&
chmod 0664 'bodies' ||
$echo 'restore of' 'bodies' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'bodies:' 'MD5 check failed'
1f7383474ecfc75883354e67afaf1b3b bodies
SHAR_EOF
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shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
test 72 -eq "$shar_count" ||
$echo 'bodies:' 'original size' '72,' 'current size' "$shar_count!"
fi
fi
# ============= page01.pre ==============
if test -f 'page01.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page01.pre' '(file already exists)'
else
$echo 'x -' extracting 'page01.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' &&
X
<P>In this tutorial, we're going to extend Tutorial 5 to create a thread-per-connection
server. This implementation will create a new thread for each client
which connects to us. The ACE_Reactor is still used but only for
accepting new connections. The Client_Handler objects won't be registered
with the reactor. Instead, they'll be responsible for monitoring
their peer() directly.
<P>
Abstract:<sup>*</sup>
<ul>
Here, we build a thread-per-connection simple server. This is the next
step from a simple single-threaded server towards a multithreaded
server.
<p>
We make use of the Strategy Pattern in this example.
The ACE_Acceptor inherits form the ACE_Acceptor_Base class which
facilitates us to implement various different concurrency strategies
depending on whether the server is single-threaded or the server creates
a new thread per connection. This also allows us to extend the
capabilities of the server in the future by implementing a different
strategy.
<p>
This information is passed on to the Client_Handler
(remember ACE_Acceptor < Client_Handler, ACE_SOCK_ACCEPTOR > ?).
The Client_Handler is an ACE_Svc_Handler as the Svc_Handler is a
derivative of the Event_Handler and is associated with
ACE_Sock_Stream. It is also derived form the ACE_Task class which allows
us to have a thread per connection.
<p>
We incorporate the data processing in the svc() method, which will be
called per thread for the thread-per-connection server.
<p>
Note that here all the Client_Handler objects aren't registered with the
reactor. The Reactor is only used to accept client connections. Once a
thread has been deicated per connection, the Client Handler object
reponsible for that client connection now takes up the job of the
reactor and handles future events.
<p>
Thus a simple, thread-per-connection server has been built which doesnt
delve too deeply into mutli-threading issues.
</ul>
<font size=-1>* Abstract by Kirthika as always</font>
SHAR_EOF
$shar_touch -am 03191459100 'page01.pre' &&
chmod 0664 'page01.pre' ||
$echo 'restore of' 'page01.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page01.pre:' 'MD5 check failed'
e9c9068f1265c1668c44f382786e1422 page01.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
test 1971 -eq "$shar_count" ||
$echo 'page01.pre:' 'original size' '1971,' 'current size' "$shar_count!"
fi
fi
# ============= page02.pre ==============
if test -f 'page02.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page02.pre' '(file already exists)'
else
$echo 'x -' extracting 'page02.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' &&
<P>Again, we begin with <A HREF="server.cpp">server.cpp.</A> If you
look closely you will see that the only difference between this and the
Tutorial 5 implementation is a single comment.
X
<P>
<HR WIDTH="100%"><FONT FACE="Arial,Helvetica"></FONT>
SHAR_EOF
$shar_touch -am 03191459100 'page02.pre' &&
chmod 0664 'page02.pre' ||
$echo 'restore of' 'page02.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page02.pre:' 'MD5 check failed'
e9e18b8add5d997189fb16e67d1467b2 page02.pre
SHAR_EOF
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shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
test 252 -eq "$shar_count" ||
$echo 'page02.pre:' 'original size' '252,' 'current size' "$shar_count!"
fi
fi
# ============= page03.pre ==============
if test -f 'page03.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page03.pre' '(file already exists)'
else
$echo 'x -' extracting 'page03.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' &&
<P>In <A HREF="client_acceptor.h">client_acceptor.h</A>, we've extended
our object just a bit. The primary reason is to allow us to select
the previous single-threaded implementation or our new thread-per-connection
implementation. Client_Acceptor itself doesn't use this information
but makes it available to the Client_Handler objects it creates.
If we wanted a single-strategy implementation, we would have made no changes
to the Tutorial 5 version of this file.
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 03191459100 'page03.pre' &&
chmod 0664 'page03.pre' ||
$echo 'restore of' 'page03.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page03.pre:' 'MD5 check failed'
40dd465ac9815a2c35375ccdbad0c98b page03.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
test 507 -eq "$shar_count" ||
$echo 'page03.pre:' 'original size' '507,' 'current size' "$shar_count!"
fi
fi
# ============= page04.pre ==============
if test -f 'page04.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page04.pre' '(file already exists)'
else
$echo 'x -' extracting 'page04.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' &&
<P><A HREF="client_handler.h">client_handler.h</A>
shows a few more changes than the previous sources. The important
change is the addition of a svc() method where our connection thread will
exist.
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 03191459100 'page04.pre' &&
chmod 0664 'page04.pre' ||
$echo 'restore of' 'page04.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page04.pre:' 'MD5 check failed'
8256aff03563fbc281403fc5bb970e69 page04.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
test 227 -eq "$shar_count" ||
$echo 'page04.pre:' 'original size' '227,' 'current size' "$shar_count!"
fi
fi
# ============= page05.pre ==============
if test -f 'page05.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page05.pre' '(file already exists)'
else
$echo 'x -' extracting 'page05.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' &&
<P><A HREF="client_handler.cpp">client_handler.cpp</A> exposes all the
things I've been hinting at. Pay special attention to the decision
made in open() as well as the bit of cleverness in svc().
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 03191459100 'page05.pre' &&
chmod 0664 'page05.pre' ||
$echo 'restore of' 'page05.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page05.pre:' 'MD5 check failed'
fe144564cd75e806b825ce878a09bfe3 page05.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
test 225 -eq "$shar_count" ||
$echo 'page05.pre:' 'original size' '225,' 'current size' "$shar_count!"
fi
fi
# ============= page06.pre ==============
if test -f 'page06.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page06.pre' '(file already exists)'
else
$echo 'x -' extracting 'page06.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page06.pre' &&
<P>That's it for Tutorial 6. With very little effort we've managed
to extend the previous single-threaded server to an implementation which
allows runtime selection of single or multi-threaded operation. In
Tutorial 7 we'll extend that again to allow a thread-pool choice in addition
to the current two.
X
<P>For reference, here's the file list again:
<UL>
<LI>
<A HREF="Makefile">Makefile</A></LI>
X
<LI>
<A HREF="client_acceptor.h">client_acceptor.h</A></LI>
X
<LI>
<A HREF="client_handler.cpp">client_handler.cpp</A></LI>
X
<LI>
<A HREF="client_handler.h">client_handler.h</A></LI>
X
<LI>
<A HREF="server.cpp">server.cpp</A></LI>
X
<LI>
<A HREF="fix.Makefile">fix.Makefile</A></LI>
</UL>
SHAR_EOF
$shar_touch -am 03191459100 'page06.pre' &&
chmod 0664 'page06.pre' ||
$echo 'restore of' 'page06.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page06.pre:' 'MD5 check failed'
0adca372a5154acf673cc373d2acaf5a page06.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page06.pre'`"
test 697 -eq "$shar_count" ||
$echo 'page06.pre:' 'original size' '697,' 'current size' "$shar_count!"
fi
fi
# ============= page02.pst ==============
if test -f 'page02.pst' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page02.pst' '(file already exists)'
else
$echo 'x -' extracting 'page02.pst' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page02.pst' &&
<HR WIDTH="100%">
X
<P>Let's move along and see what happend to the Client_Acceptor.
X
<P>
SHAR_EOF
$shar_touch -am 03191459100 'page02.pst' &&
chmod 0664 'page02.pst' ||
$echo 'restore of' 'page02.pst' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page02.pst:' 'MD5 check failed'
0188a5ff7cacc123676e420ac5432207 page02.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pst'`"
test 89 -eq "$shar_count" ||
$echo 'page02.pst:' 'original size' '89,' 'current size' "$shar_count!"
fi
fi
# ============= page03.pst ==============
if test -f 'page03.pst' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page03.pst' '(file already exists)'
else
$echo 'x -' extracting 'page03.pst' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page03.pst' &&
<HR WIDTH="100%">
X
<P>Ok, so far we haven't done much to change our concurrency strategy.
Let's move on to the Client_Handler and see if it has changed any.
X
<P>
SHAR_EOF
$shar_touch -am 03191459100 'page03.pst' &&
chmod 0664 'page03.pst' ||
$echo 'restore of' 'page03.pst' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page03.pst:' 'MD5 check failed'
7743577254d06f5848b5e50f3b6c3014 page03.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pst'`"
test 168 -eq "$shar_count" ||
$echo 'page03.pst:' 'original size' '168,' 'current size' "$shar_count!"
fi
fi
# ============= page04.pst ==============
if test -f 'page04.pst' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page04.pst' '(file already exists)'
else
$echo 'x -' extracting 'page04.pst' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page04.pst' &&
<HR WIDTH="100%">
X
<P>So... we've added a svc() method and alluded to changes in open().
Let's move on to the object definition and see what all the fuss is about.
X
<P>
SHAR_EOF
$shar_touch -am 03191459100 'page04.pst' &&
chmod 0664 'page04.pst' ||
$echo 'restore of' 'page04.pst' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page04.pst:' 'MD5 check failed'
dfe0897cc3f000b69c16c87dd1596281 page04.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pst'`"
test 175 -eq "$shar_count" ||
$echo 'page04.pst:' 'original size' '175,' 'current size' "$shar_count!"
fi
fi
# ============= page05.pst ==============
if test -f 'page05.pst' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page05.pst' '(file already exists)'
else
$echo 'x -' extracting 'page05.pst' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page05.pst' &&
<HR WIDTH="100%">
<P>
X Did you notice the <i>THR_DETACHED</i> flag on the call to
X <i>activate()</i>? Threads, like any system resource, are a
X limited resource. Unless we intend to <i>join()</i> or
X <i>wait()</i> for the new thread later, we want use THR_DETACHED
X so that we don't cause a leak. In fact, in most cases, you'll
X want to specify THR_DETACHED because it's just easier.
<p>
X Another handy flag for use with <i>activate()</i> is
X <i>THR_NEW_LWP</i>. That's short for <i>Light Weight
X Process</i>. If you've got a multiprocessor, this flag will
X allocate a new schedulable process and decrease the odds of your
X threads all fighting for the same process. Of course, if you
X have a uni-processor, it will neither help nor hurt. Since I
X developed these on a uni-processor, I've been a bit inconsistent
X in the use of <i>THR_NEW_LWP</i>.
X
<P>Well, that's it! After all the talk & the hype, you would
have expected it to be more difficult to create a multi-threaded server.
Surprise! It really is that easy. You still have to handle
contention issues which we haven't addressed here and that is a rather
nasty topic. Still, for the simple case, this is all you have to
do.
X
<P>The next page is the last for this tutorial. Head on over there
& we'll round up the file list one last time.
X
<P>
SHAR_EOF
$shar_touch -am 03191459100 'page05.pst' &&
chmod 0664 'page05.pst' ||
$echo 'restore of' 'page05.pst' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page05.pst:' 'MD5 check failed'
0589bdf4e09c3c1671f64fd98e8e7747 page05.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pst'`"
test 1418 -eq "$shar_count" ||
$echo 'page05.pst:' 'original size' '1418,' 'current size' "$shar_count!"
fi
fi
rm -fr _sh32413
exit 0
