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How to observe events ?
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<h1>
HTML_Progress2 : The Definitive Guide
</h1>
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How to observe events ?
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<h2 class="title c1">
<a name="listener.observe" id="listener.observe"></a>How to observe
events ?
</h2>
</div>
<p>
Suppose we decide to send a mail after a process is over (progress
meter reach 100%) and keep aware some users. We will see how to do this
now.
</p>
<p>
<span class="bold"><strong>First step</strong></span> is to declare a
function (user callback) that will observe all progress meter events.
</p>
<p>
Interface of such function (callback) is pretty easy. It requires only
one argument passed by reference (<code class=
"varname">$notification</code>) and that should contains a <span class=
"emphasis"><em>PEAR::Event_Dispatcher</em></span> instance.
</p>
<p>
Here are, in purpose of our tutorial, a function that will observe
events and send a mail, at end of process, to webmaster@site.com with a
short message that gave time elapsed.
</p>
<p>
<span class="bold"><strong>Second step</strong></span> is to attach
this function (user callback) to the progress meter with the
<code class="methodname">addListener()</code> method.
</p>
<div class="php c2">
<ol>
<li class="li1">
<div class="de1">
<span class="kw2"><?php</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw1">require_once</span> <span class=
"st0">'HTML/Progress2.php'</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2">function</span> getmicrotime<span class=
"br0">(</span><span class="re1">$time</span><span class=
"br0">)</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="br0">{</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw3">list</span><span class=
"br0">(</span><span class="re1">$usec</span><span class=
"sy0">,</span> <span class="re1">$sec</span><span class=
"br0">)</span> <span class="sy0">=</span> <span class=
"kw3">explode</span><span class="br0">(</span><span class="st0">'
'</span><span class="sy0">,</span> <span class=
"re1">$time</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw1">return</span> <span class=
"br0">(</span><span class="br0">(</span>float<span class=
"br0">)</span><span class="re1">$usec</span> <span class=
"sy0">+</span> <span class="br0">(</span>float<span class=
"br0">)</span><span class="re1">$sec</span><span class=
"br0">)</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1">
<div class="de1">
<span class="br0">}</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="kw2">function</span> myObserver<span class=
"br0">(</span><span class="sy0">&</span><span class=
"re1">$notification</span><span class="br0">)</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="br0">{</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw3">static</span> <span class=
"re1">$time_start</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="re1">$notifyName</span> <span class=
"sy0">=</span> <span class="re1">$notification</span><span class=
"sy0">-></span><span class=
"me1">getNotificationName</span><span class=
"br0">(</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="re1">$notifyInfo</span> <span class=
"sy0">=</span> <span class="re1">$notification</span><span class=
"sy0">-></span><span class=
"me1">getNotificationInfo</span><span class=
"br0">(</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw1">switch</span> <span class=
"br0">(</span><span class="re1">$notifyName</span><span class=
"br0">)</span> <span class="br0">{</span>
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="kw1">case</span>
<span class="st0">'onSubmit'</span><span class="sy0">:</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"re1">$time_start</span> <span class="sy0">=</span>
getmicrotime<span class="br0">(</span><span class=
"re1">$notifyInfo</span><span class="br0">[</span><span class=
"st0">'time'</span><span class="br0">]</span><span class=
"br0">)</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"kw1">break</span><span class="sy0">;</span>
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="kw1">case</span>
<span class="st0">'onLoad'</span><span class="sy0">:</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"re1">$time_elapse</span> <span class="sy0">=</span>
getmicrotime<span class="br0">(</span><span class=
"re1">$notifyInfo</span><span class="br0">[</span><span class=
"st0">'time'</span><span class="br0">]</span><span class=
"br0">)</span> <span class="sy0">-</span> <span class=
"re1">$time_start</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"kw3">error_log</span> <span class="br0">(</span><span class=
"st0">'process ID=5 is over (elapse time = '</span><span class=
"sy0">.</span> <span class="re1">$time_elapse</span> <span class=
"sy0">.</span> <span class="st0">' sec.)'</span><span class=
"sy0">,</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="nu0">3</span><span class=
"sy0">,</span> <span class=
"st0">'progress_observer.log'</span><span class=
"br0">)</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"kw1">break</span><span class="sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="br0">}</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="br0">}</span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1">
<div class="de1">
<span class="re1">$pb</span> <span class="sy0">=</span>
<span class="kw2">new</span> HTML_Progress2<span class=
"br0">(</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="re1">$pb</span><span class=
"sy0">-></span><span class=
"me1">setAnimSpeed</span><span class="br0">(</span><span class=
"nu0">200</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="re1">$pb</span><span class=
"sy0">-></span><span class=
"me1">setIncrement</span><span class="br0">(</span><span class=
"nu0">10</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1 ln-xtra">
<div class="de1">
<span class="re1">$pb</span><span class=
"sy0">-></span><span class=
"me1">addListener</span><span class="br0">(</span><span class=
"st0">'myObserver'</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2">?></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"><!</span>DOCTYPE html <span class=
"kw2">PUBLIC</span> <span class="st0">"-//W3C//DTD XHTML 1.0
Strict//EN"</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class=
"st0">"http://www.w3c.org/TR/xhtml1/DTD/xhtml1-strict.dtd"</span><span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"><</span>html xmlns<span class=
"sy0">=</span><span class=
"st0">"http://www.w3.org/1999/xhtml"</span> xml<span class=
"sy0">:</span>lang<span class="sy0">=</span><span class=
"st0">"en"</span><span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"><</span>head<span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"><</span>title<span class=
"sy0">></span>Observer Pattern<span class=
"sy0"></</span>title<span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2"><?php</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw3">echo</span> <span class=
"re1">$pb</span><span class="sy0">-></span><span class=
"me1">getStyle</span><span class="br0">(</span><span class=
"kw2">false</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw3">echo</span> <span class=
"re1">$pb</span><span class="sy0">-></span><span class=
"me1">getScript</span><span class="br0">(</span><span class=
"kw2">false</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2">?></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"></</span>head<span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"><</span>body<span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2"><?php</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="re1">$pb</span><span class=
"sy0">-></span><span class="me1">display</span><span class=
"br0">(</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="re1">$pb</span><span class=
"sy0">-></span><span class="me1">run</span><span class=
"br0">(</span><span class="br0">)</span><span class=
"sy0">;</span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="kw2">?></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"></</span>body<span class="sy0">></span>
</div>
</li>
<li class="li1">
<div class="de1">
<span class="sy0"></</span>html<span class="sy0">></span>
</div>
</li>
</ol>
</div>
<div class="variablelist">
<dl>
<dt>
<span class="term">Line 15 :</span>
</dt>
<dd>
<p>
<code class="varname">$notifyName</code> contains event name
triggered. Three issues : <span class=
"emphasis"><em>onSubmit</em></span>, <span class=
"emphasis"><em>onLoad</em></span>, <span class=
"emphasis"><em>onChange</em></span>.
</p>
<div class="caution c3">
<table border="0" summary="Caution">
<tr>
<td rowspan="2" align="center" valign="top" width="48">
<img alt="[Caution]" src="img/admons/caution.png" />
</td>
<th align="left">
Caution
</th>
</tr>
<tr>
<td align="left" valign="top">
Event name is case sensitive: <span class=
"emphasis"><em>onsubmit</em></span> does not match
<span class="emphasis"><em>onSubmit</em></span>.
</td>
</tr>
</table>
</div>
</dd>
<dt>
<span class="term">Line 16 :</span>
</dt>
<dd>
<p>
<code class="varname">$notifyInfo</code> contains array of
additional informations.
</p>
<p>
For example :
</p>
<pre class="programlisting">
Array
(
[handler] => run
[value] => 100
[sender] => html_progress2
[time] => 0.26838700 1127382686
)
</pre>
</dd>
<dt>
<span class="term">Line 19 :</span>
</dt>
<dd>
<p>
When progress meter start, it trigger a <span class=
"emphasis"><em>onSubmit</em></span> event through the
<code class="methodname">run()</code> method. This event is
catched into user callback and with help of additionnal info we
compute and store start time.
</p>
</dd>
<dt>
<span class="term">Line 22 :</span>
</dt>
<dd>
<p>
When progress meter reach 100%, it trigger a <span class=
"emphasis"><em>onLoad</em></span> event through the <code class=
"methodname">run()</code> method. This event is catched into user
callback. We compute elapse time and send final result by mail to
the webmaster of site.com
</p>
</dd>
<dt>
<span class="term">Lines 11-28, 33 :</span>
</dt>
<dd>
<p>
All observers attached, are notified by each event. It's up to
you to decide if you have to process an event or not. Here we
will proceed only two events: <span class=
"emphasis"><em>onSubmit</em></span>, <span class=
"emphasis"><em>onLoad</em></span>.
</p>
</dd>
</dl>
</div>
<p>
<span class="bold"><strong>Third step</strong></span> (optional) is
stop listen events and then detach user function (callback) to the
progress meter with the <code class=
"methodname">removeListener()</code> method.
</p>
<div class="note c3">
<table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="48">
<img alt="[Note]" src="img/admons/note.png" />
</td>
<th align="left">
Note
</th>
</tr>
<tr>
<td align="left" valign="top">
While there are any observers attached, progress meter will
continue to notify them of each event when they occured.
</td>
</tr>
</table>
</div>
</div>
<table class="progress2Footer">
<tr>
<td align="left">
HTML_Progress2 : The Definitive Guide
</td>
<td align="right">
v 2.4.0 : April 20, 2007
</td>
</tr>
</table>
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<tr>
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Chapter 8. Quick Start with HTML_Progress2_Monitor
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