#!/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/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
# 1090 -rw-rw-r-- page01.pre
# 262 -rw-rw-r-- page02.pre
# 395 -rw-rw-r-- page03.pre
# 154 -rw-rw-r-- page04.pre
# 182 -rw-rw-r-- page05.pre
# 448 -rw-rw-r-- page06.pre
# 393 -rw-rw-r-- page02.pst
# 398 -rw-rw-r-- page03.pst
# 162 -rw-rw-r-- page04.pst
# 447 -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 _sh32620; 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 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 \
|| $echo 'hdr:' 'MD5 check failed'
1acf94beccfa9e953b2f55e02a0bb2e6 hdr
SHAR_EOF
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test 430 -eq "$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 \
|| $echo 'bodies:' 'MD5 check failed'
3ad29f0a25bfe156b37630c9ee9f715c bodies
SHAR_EOF
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shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
test 56 -eq "$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 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 \
|| $echo 'page01.pre:' 'MD5 check failed'
c9933ac2153b0a56043967ea9c7eb0c9 page01.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
test 1090 -eq "$shar_count" ||
$echo 'page01.pre:' 'original size' '1090,' 'current size' "$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 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 \
|| $echo 'page02.pre:' 'MD5 check failed'
91f6bbd4cdf687d420bd52bf6685e2d2 page02.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
test 262 -eq "$shar_count" ||
$echo 'page02.pre:' 'original size' '262,' 'current size' "$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 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 \
|| $echo 'page03.pre:' 'MD5 check failed'
134a60947715be2de3ca2589a3e652e2 page03.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
test 395 -eq "$shar_count" ||
$echo 'page03.pre:' 'original size' '395,' 'current size' "$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 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 \
|| $echo 'page04.pre:' 'MD5 check failed'
8989e75934f20e9b74d38a2d3687613a page04.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
test 154 -eq "$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 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 \
|| $echo 'page05.pre:' 'MD5 check failed'
ed1b82e232cc376efa7b78f391c893bd page05.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
test 182 -eq "$shar_count" ||
$echo 'page05.pre:' 'original size' '182,' 'current size' "$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 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 \
|| $echo 'page06.pre:' 'MD5 check failed'
64afabb236ea02927914d03f258e620b page06.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page06.pre'`"
test 448 -eq "$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 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 \
|| $echo 'page02.pst:' 'MD5 check failed'
ab34347fca8c20953552cf0ecebd394f page02.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pst'`"
test 393 -eq "$shar_count" ||
$echo 'page02.pst:' 'original size' '393,' 'current size' "$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 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 \
|| $echo 'page03.pst:' 'MD5 check failed'
01e400b5683e0e1c3dfa25cc8120bfa6 page03.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pst'`"
test 398 -eq "$shar_count" ||
$echo 'page03.pst:' 'original size' '398,' 'current size' "$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 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 \
|| $echo 'page04.pst:' 'MD5 check failed'
245db1d5e74203bf085369bb47d646db page04.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pst'`"
test 162 -eq "$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 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 \
|| $echo 'page05.pst:' 'MD5 check failed'
a7f519237d11a25b28af7aa33f5aaf30 page05.pst
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pst'`"
test 447 -eq "$shar_count" ||
$echo 'page05.pst:' 'original size' '447,' 'current size' "$shar_count!"
fi
fi
rm -fr _sh32620
exit 0
