#!/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 1999-01-26 20:15 EST by <jcej@chiroptera.tragus.org>.
# Source directory was `/var/home/jcej/projects/ACE_wrappers/docs/tutorials/012'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode       name
# ------ ---------- ------------------------------------------
#    430 -rw-rw-r-- hdr
#     56 -rw-rw-r-- bodies
#   1093 -rw-rw-r-- page01.pre
#    263 -rw-rw-r-- page02.pre
#    397 -rw-rw-r-- page03.pre
#    154 -rw-rw-r-- page04.pre
#    183 -rw-rw-r-- page05.pre
#    448 -rw-rw-r-- page06.pre
#    395 -rw-rw-r-- page02.pst
#    399 -rw-rw-r-- page03.pst
#    162 -rw-rw-r-- page04.pst
#    449 -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 _sh31139; 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="Author" CONTENT="James CE Johnson">
X   <TITLE>ACE Tutorial 012</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
X
<CENTER><B><FONT SIZE=+2>ACE Tutorial 012</FONT></B></CENTER>
X
<CENTER><B><FONT SIZE=+2>Passing classes through ACE_Message_Queue</FONT></B></CENTER>
X
X
<P>
<HR WIDTH="100%">
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'hdr:' 'MD5 check failed'
1acf94beccfa9e953b2f55e02a0bb2e6  hdr
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`"
    test 430 -eq "$shar_count" ||
    $echo 'hdr:' 'original size' '430,' 'current size' "$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
work.h
block.h
message_queue.cpp
task.h task.cpp
SHAR_EOF
  $shar_touch -am 0124160199 '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 \
    || $echo 'bodies:' 'MD5 check failed'
3ad29f0a25bfe156b37630c9ee9f715c  bodies
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
    test 56 -eq "$shar_count" ||
    $echo 'bodies:' 'original size' '56,' 'current size' "$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' &&
<P>
Last time around we put an object into a message queue by using the
copy() method to create a duplicate of the object.  That's probably OK 
for simple objects that aren't very large.  However, if you have an
object that contains pointers or tons of data then that approach is
going to cause problems.
<P>
What we'll do in this tutorial is specialize the ACE_Message_Block 
object so that it can carry our data more efficiently.  As you'll see, 
this isn't very difficult at all.
<P>
Kirthika's abstract:
<UL>
Here, a Message_Block class is derived from ACE_Message_Block and is
used to hold a pointer to the object of class Work. Also, the block has
a header containing text. This example simply illustrates a cleaner way
of utilizing Message_Blocks to store objects rather than copying their
contents.
<P>
The ACE_Barrier class has been used in the Task class which blocks the
threads until all of them are rearing to go and grab a block from the
queue and process it.
<P>
Thus a message queue can be used to accomplish a variety of tasks by
storing a object pointer in the blocks.
</UL>
SHAR_EOF
  $shar_touch -am 0126201599 '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 \
    || $echo 'page01.pre:' 'MD5 check failed'
5e7f58b50e75c303325b71866a2a4a4a  page01.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
    test 1093 -eq "$shar_count" ||
    $echo 'page01.pre:' 'original size' '1093,' 'current size' "$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' &&
We normally start by looking at main() and work our way out from
there.  This time, I want to start by showing you the ACE_Message_Block
derivative but before that, I have to introduce you to the Work object 
and it's baseclass Unit_Of_Work
<P>
<HR WIDTH="100%">
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page02.pre:' 'MD5 check failed'
67c405a8085b9ad581912c2aec135ed4  page02.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
    test 263 -eq "$shar_count" ||
    $echo 'page02.pre:' 'original size' '263,' 'current size' "$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 the previous tutorial we moved our complex data into the queue by
copy()ing it directly into the message block's data area.  I hope that 
most readers got a queasy feeling when I did that.  It just isn't a
good idea...
<P>
A better idea would be to teach the message queue about our data types 
(or at least a baseclass) so that it can more efficiently handle things:
<P>
<HR WIDTH="100%">
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page03.pre:' 'MD5 check failed'
d8f77e8098d5086c71c164de8a78c29c  page03.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
    test 397 -eq "$shar_count" ||
    $echo 'page03.pre:' 'original size' '397,' 'current size' "$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>
Ok, finally we get to main().  Sorry for the diversion but it was
important to lay some of that groundwork before getting here.
<P>
<HR WIDTH="100%">
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page04.pre:' 'MD5 check failed'
8989e75934f20e9b74d38a2d3687613a  page04.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
    test 154 -eq "$shar_count" ||
    $echo 'page04.pre:' 'original size' '154,' 'current size' "$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>
The Task is the only object we've not been through yet.  I'll go ahead 
and show both the header and cpp on this one page since the header
isn't very large.
<P>
<HR WIDTH="100%">
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page05.pre:' 'MD5 check failed'
499934db529597846d10ca45610bc52e  page05.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
    test 183 -eq "$shar_count" ||
    $echo 'page05.pre:' 'original size' '183,' 'current size' "$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>
Once again, we come to the end of a tutorial.  By creating a simple
specialization of ACE_Message_Block, we've been able to remove a lot
of complexity and erorr potential from our previous implementation.
<UL>
<LI><A HREF="Makefile">Makefile</A>
<LI><A HREF="message_queue.cpp">message_queue.cpp</A>
<LI><A HREF="work.h">work.h</A>
<LI><A HREF="block.h">block.h</A>
<LI><A HREF="task.h">task.h</A>
<LI><A HREF="task.cpp">task.cpp</A>
</UL>
<P>
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page06.pre:' 'MD5 check failed'
64afabb236ea02927914d03f258e620b  page06.pre
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page06.pre'`"
    test 448 -eq "$shar_count" ||
    $echo 'page06.pre:' 'original size' '448,' 'current size' "$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%">
<P>
This is basically the same as the <i>DataBase</i> in the previous
tutorial but I've changed the name to be more generic.  The feeling is 
that a <i>Data</i> object would be a C struct but an <i>Work</i>
object would be a class with methods.
<P>
Now that you know what we'll be putting into the queue, lets go to the 
next page where I specialize the ACE_Message_Block.
<P>
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page02.pst:' 'MD5 check failed'
961a6ad181e25a24b2500abe013b5379  page02.pst
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pst'`"
    test 395 -eq "$shar_count" ||
    $echo 'page02.pst:' 'original size' '395,' 'current size' "$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%">
<P>
Ok, this looks pretty good.  We just construct our specialized
Message_Block instead of the generic ACE_Message_Block and let it
carry our data along.  When our application is done with the message
block and release()es it, we know that our work object will also be
taken care of.
<P>
Let's now go to main() and see what we had to change there to use this 
specialization.
<P>
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page03.pst:' 'MD5 check failed'
282e52e360c416f48db0dc454354bfda  page03.pst
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pst'`"
    test 399 -eq "$shar_count" ||
    $echo 'page03.pst:' 'original size' '399,' 'current size' "$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%">
<P>
That certainly looks cleaner than the previous approach!  If you
blink, you'll miss the part where the Work object goes into the Queue.
<P>
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page04.pst:' 'MD5 check failed'
245db1d5e74203bf085369bb47d646db  page04.pst
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pst'`"
    test 162 -eq "$shar_count" ||
    $echo 'page04.pst:' 'original size' '162,' 'current size' "$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>
Like main() this is actually simpler than the previous tutorial.  It's 
much cleaner to carry around a pointer to the object we're working
with than to try copying data.
<P>
The only complication is the new ACE_Barrier.  It's a pretty simple
object that makes it easy for you to synch threads in this way.  You
could do some fancy tricks with mutexes, counters & semaphores but why 
bother when the Barrier already exists.
<P>
SHAR_EOF
  $shar_touch -am 0124160599 '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 \
    || $echo 'page05.pst:' 'MD5 check failed'
1db9b33059c7da0ee0b30f0d077bd443  page05.pst
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pst'`"
    test 449 -eq "$shar_count" ||
    $echo 'page05.pst:' 'original size' '449,' 'current size' "$shar_count!"
  fi
fi
rm -fr _sh31139
exit 0
