Enter 2004 June/ENTER.ISO/files/xampp-win32-1.4.5-installer.exe/xampp/observer.pkg

Text File | 2004-03-24 | 10.8 KB | 399 lines

<refentry id="{@id}">
 <refnamediv>
  <refname>Using Progress Observers</refname>
  <refpurpose>introduction to HTML_Progress observer mechanism</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <author>
    by Laurent Laville
    <authorblurb>{@link mailto:[e-mail]}</authorblurb>
   </author>
   <copyright>November 2003, Laurent Laville</copyright>
   <releaseinfo>HTML_Progress 1.0+</releaseinfo>
  </refsynopsisdivinfo>
 </refsynopsisdiv>
 {@toc}
 <refsect1 id="{@id intro}">
  <title>Introduction </title>
  <para>
   The {@link HTML_Progress_Observer} class provides an implementation of the observer pattern.
   In the content of the HTML_Progress package, they provide a mechanism which you can
   examine each important event as it is happened. This allows the implementation of
   special behavior based on the value of the progress element.
  </para>
  <para>
   Creating a progress observer involves implementing a subclass of the
   {@link HTML_Progress_Observer} class. The subclass must override the base class's
   {@link HTML_Progress_Observer::notify()} method. This method is passed a hash containing
   event name and value.
  </para>
  <para>
   At this time, no concrete observer implementations are distributed with the HTML_Progress
   package. But you could find some good examples named {@tutorial observer.pkg#examples.standard},
   {@tutorial observer.pkg#examples.simple}, {@tutorial observer.pkg#examples.complex} available
   in examples subdirectory of bundle distribution.
  </para>
  <para>
   Now we will learn how to catch and manage specific events and respond to them in a specific way.
  </para>
 </refsect1>
 <refsect1 id="{@id using}">
  <title>Using Progress Observers </title>
  <para>
   If you <important>do not override the base class</important>,
   as in {@tutorial observer.pkg#examples.standard} example, the default behavior is to write
   events (setminimum, setmaximum, setvalue)
   into a file <emphasis>progress_observer.log</emphasis> in current directory.
  </para>
  <para>
   If you decide to <important>override the base class with <emphasis>MyObserver</emphasis>
   object</important>, as in {@tutorial observer.pkg#examples.simple} example,
   the new behavior could be to write events (setminimum, setmaximum, setvalue)
   into a file <emphasis>observer_complex.log</emphasis>
   ({@tutorial observer.pkg#examples.simple line 40}),
   or just send it to browser screen ({@tutorial observer.pkg#examples.simple line 39}).
  </para>
  <para>
   In the last example, {@tutorial observer.pkg#examples.complex}, <important>the base class
   was overridden by <emphasis>Bar1Observer</emphasis> object</important>
   ({@tutorial observer.pkg#examples.complex line 6}), to allow a double vertical bar synchronized.
   <para><graphic fileref="../media/screenshots/observer_complex.png"></graphic></para>
  </para>
  <para>
   But all these 3 examples won't work if we do not attach the observer object to the progress bar,
   as a listener. To do so, use {@link HTML_Progress::addListener()} method. If you want to detach
   the observer object, use {@link HTML_Progress::removeListener()} method. And if you want to
   check what listeners are attached to progress bar, then use {@link HTML_Progress::getListeners()}
   method.
  </para>
 </refsect1>
 <refsect1 id="{@id examples}">
  <title>Examples </title>
  <refsect2 id="{@id standard}">
   <title>observer_standard.php</title>
   <para>
    <programlisting role="php">
    <![CDATA[
<?php
require_once ('HTML/Progress.php');
require_once ('HTML/Progress/observer.php');

// 1. Creates ProgressBar
$bar = new HTML_Progress();
$bar->setBorderPainted(true);
$bar->setIncrement(10);

// 2. Creates and attach a listener
$observer = new HTML_Progress_Observer();

$ok = $bar->addListener($observer);
if (!$ok) {
    die ("Cannot add a valid listener to progress bar !");
}

// 3. Changes look-and-feel of ProgressBar
$ui =& $bar->getUI();
$ui->setBorderAttributes('width = 2');   // border: 2px, solid, #000000
$ui->setComment('Standard Observer ProgressBar example');

?>
<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3c.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Standard Observer ProgressBar example</title>
<style type="text/css">
<!--
<?php echo $bar->getStyle(); ?>

body {
    background-color: #FFFFFF;
    color: #000000;
    font-family: Verdana, Arial;
}

a:visited, a:active, a:link {
    color: navy;
}
// -->
</style>
<script type="text/javascript">
<!--
<?php echo $ui->getScript(); ?>
//-->
</script>
</head>
<body>

<?php
echo $bar->toHTML();

do {
    $bar->display();
    if ($bar->getPercentComplete() == 1) {
        break;   // the progress bar has reached 100%
    }
    $bar->incValue();
} while(1);
?>

</body>
</html>
    ]]>
    </programlisting>
   </para>
  </refsect2>
  <refsect2 id="{@id simple}">
   <title>observer_simple.php</title>
   <para>
    <programlisting role="php">
    <![CDATA[
<?php
require_once ('HTML/Progress.php');
require_once ('HTML/Progress/observer.php');

// 1. Defines ProgressBar observer
class MyObserver extends HTML_Progress_Observer
{
    var $_console;
    var $_out;

    function MyObserver($out)
    {
        $this->_console = '.' . DIRECTORY_SEPARATOR . 'observer_complex.log';
        $this->HTML_Progress_Observer();
        $this->_out = strtolower($out);
    }

    function notify($event)
    {
        if (is_array($event)) {
            $log = isset($event['log']) ? $event['log'] : "undefined event id.";
            $val = isset($event['value']) ? $event['value'] : "unknown value";
            $msg = "$log = $val";
        } else {
            $msg = $event;
        }
        if ($this->_out == 'file') {
            error_log("$msg \n", 3, $this->_console);
        } else {
            print ("$msg <br />\n");
    }
    }
}

// 2. Creates ProgressBar
$bar = new HTML_Progress();
$bar->setIncrement(5);

// 3. Creates and attach a listener
$observer = new MyObserver('screen');
//$observer = new MyObserver('file');

$ok = $bar->addListener($observer);
if (!$ok) {
    die ("Cannot add a valid listener to progress bar !");
}

// 4. Changes look-and-feel of ProgressBar
$ui = $bar->getUI();
$ui->setStringAttributes('color = red');
$ui->setComment('Simple Observer ProgressBar example');

?>
<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3c.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Simple Observer ProgressBar example</title>
<style type="text/css">
<!--
<?php echo $bar->getStyle(); ?>
// -->
</style>
<script type="text/javascript">
<!--
<?php echo $ui->getScript(); ?>
//-->
</script>
</head>
<body>

<?php
echo $bar->toHTML();

do {
    $bar->display();
    if ($bar->getPercentComplete() == 1) {
        break;   // the progress bar has reached 100%
    }
    $bar->incValue();
} while(1);
?>

</body>
</html>
    ]]>
    </programlisting>
   </para>
  </refsect2>
  <refsect2 id="{@id complex}">
   <title>observer_complex.php</title>
   <para>
    <programlisting role="php">
    <![CDATA[
<?php
require_once ('HTML/Progress.php');
require_once ('HTML/Progress/observer.php');

// 1. Defines ProgressBar observer
class Bar1Observer extends HTML_Progress_Observer
{
    function Bar1Observer()
    {
        $this->HTML_Progress_Observer();
    }

    function notify($event)
    {
        global $bar2;

        if (is_array($event)) {
            $log = isset($event['log']) ? $event['log'] : "undefined event id.";
            $val = isset($event['value']) ? $event['value'] : "unknown value";

            switch (strtolower($log)) {
             case 'incvalue':
                 // if you want to do special on each step of progress bar1; it's here !!!
                 break;
             case 'setvalue':
                 if ($val == 0) {
                     // updates $bar2 because $bar1 has completed a full loop
                     $bar2->incValue();
                     $bar2->display();
                 }
             default:
            }
        }
    }
}

// 2. Creates ProgressBar
$bar1 = new HTML_Progress(HTML_PROGRESS_BAR_VERTICAL);
$bar1->setIncrement(10);
$bar1->setIdent('PB1');

$bar2 = new HTML_Progress(HTML_PROGRESS_BAR_VERTICAL);
$bar2->setIncrement(25);
$bar2->setIdent('PB2');
$bar2->setBorderPainted(true);

// 3. Creates and attach a listener
$observer = new Bar1Observer();

$ok = $bar1->addListener($observer);
if (!$ok) {
    die ("Cannot add a valid listener to progress bar !");
}

// 4. Changes look-and-feel of ProgressBar
$ui1 =& $bar1->getUI();
$ui1->setComment('Complex Observer ProgressBar example');
$ui1->setTabOffset(1);
$ui1->setProgressAttributes(array(
    'background-color' => '#e0e0e0'
        ));
$ui1->setStringAttributes(array(
    'valign' => 'left',
    'color'  => 'red',
    'background-color' => 'lightblue'
    ));

$ui2 =& $bar2->getUI();
$ui2->setTabOffset(1);
$ui2->setBorderAttributes(array(
        'width' => 1,
        'style' => 'solid',
        'color' => 'navy'
        ));
$ui2->setCellAttributes(array(
        'active-color' => '#3874B4',
        'inactive-color' => '#EEEECC'
        ));
$ui2->setStringAttributes(array(
        'width'  => '100',
    'align'  => 'center',
    'valign' => 'right',
    'color'  => 'yellow',
    'background-color' => 'lightblue'
    ));
?>
<!DOCTYPE html
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3c.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>Complex Observer ProgressBar example</title>
<style type="text/css">
<!--
<?php
echo $bar1->getStyle();
echo $bar2->getStyle();
?>
table.container {
    background-color: lightblue;
    border: 2;
    border-color: navy;
    border-style: dashed;
    cell-spacing: 4;
    cell-padding: 8;
    width: 50%;
}
// -->
</style>
<script type="text/javascript">
<!--
<?php echo $ui1->getScript(); ?>
//-->
</script>
</head>
<body>

<table class="container">
<tr>
    <td width="25%" align="center">
<?php echo $bar1->toHTML(); ?>
    </td>
    <td width="25%" align="center">
<?php echo $bar2->toHTML(); ?>
    </td>
</tr>
</table>

<?php
do {
    $bar1->display();
    if ($bar1->getPercentComplete() == 1) {
        $bar1->setValue(0);  // the 1st progress bar has reached 100%, do a new loop
    } else {
        $bar1->incValue();   // updates 1st progress bar
    }
} while($bar2->getPercentComplete() < 1);
?>

</body>
</html>
    ]]>
    </programlisting>
   </para>
  </refsect2>
 </refsect1>
</refentry>