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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Examples</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="objaggregation.examples.html">Examples</a></div> <div class="next" style="text-align: right; float: right;"><a href="ref.objaggregation.html">Object Aggregation Functions</a></div> <div class="up"><a href="objaggregation.examples.html">Examples</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="objaggregation.examples2" class="section"> <h2 class="title">Examples</h2> <p class="para"> We define 3 classes, each implementing a different storage method: </p> <p class="para"> <div class="example"> <p><b>Example #1 storage_classes.inc</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">FileStorage </span><span style="color: #007700">{<br /> var </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /><br /> function </span><span style="color: #0000BB">FileStorage</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">) <br /> {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /> }<br /> <br /> function </span><span style="color: #0000BB">write</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">) <br /> {<br /> </span><span style="color: #0000BB">$fp </span><span style="color: #007700">= </span><span style="color: #0000BB">fopen</span><span style="color: #007700">(</span><span style="color: #0000BB">name</span><span style="color: #007700">, </span><span style="color: #DD0000">"w"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">fwrite</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">, </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">fclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">);<br /> }<br />}<br /><br />class </span><span style="color: #0000BB">WDDXStorage </span><span style="color: #007700">{<br /> var </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /> var </span><span style="color: #0000BB">$version </span><span style="color: #007700">= </span><span style="color: #DD0000">"1.0"</span><span style="color: #007700">;<br /> var </span><span style="color: #0000BB">$_id</span><span style="color: #007700">; </span><span style="color: #FF8000">// "private" variable<br /><br /> </span><span style="color: #007700">function </span><span style="color: #0000BB">WDDXStorage</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">) <br /> {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">_id </span><span style="color: #007700">= </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">_genID</span><span style="color: #007700">();<br /> }<br /><br /> function </span><span style="color: #0000BB">store</span><span style="color: #007700">() <br /> {<br /> if (</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">_id</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$pid </span><span style="color: #007700">= </span><span style="color: #0000BB">wddx_packet_start</span><span style="color: #007700">(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">_id</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">wddx_add_vars</span><span style="color: #007700">(</span><span style="color: #0000BB">$pid</span><span style="color: #007700">, </span><span style="color: #DD0000">"this->data"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$packet </span><span style="color: #007700">= </span><span style="color: #0000BB">wddx_packet_end</span><span style="color: #007700">(</span><span style="color: #0000BB">$pid</span><span style="color: #007700">);<br /> } else {<br /> </span><span style="color: #0000BB">$packet </span><span style="color: #007700">= </span><span style="color: #0000BB">wddx_serialize_value</span><span style="color: #007700">(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data</span><span style="color: #007700">);<br /> }<br /> </span><span style="color: #0000BB">$dbh </span><span style="color: #007700">= </span><span style="color: #0000BB">dba_open</span><span style="color: #007700">(</span><span style="color: #DD0000">"varstore"</span><span style="color: #007700">, </span><span style="color: #DD0000">"w"</span><span style="color: #007700">, </span><span style="color: #DD0000">"gdbm"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">dba_insert</span><span style="color: #007700">(</span><span style="color: #0000BB">md5</span><span style="color: #007700">(</span><span style="color: #0000BB">uniqid</span><span style="color: #007700">(</span><span style="color: #DD0000">""</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">)), </span><span style="color: #0000BB">$packet</span><span style="color: #007700">, </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">dba_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">);<br /> }<br /><br /> </span><span style="color: #FF8000">// a private method<br /> </span><span style="color: #007700">function </span><span style="color: #0000BB">_genID</span><span style="color: #007700">() <br /> {<br /> return </span><span style="color: #0000BB">md5</span><span style="color: #007700">(</span><span style="color: #0000BB">uniqid</span><span style="color: #007700">(</span><span style="color: #0000BB">rand</span><span style="color: #007700">(), </span><span style="color: #0000BB">true</span><span style="color: #007700">));<br /> }<br />}<br /><br />class </span><span style="color: #0000BB">DBStorage </span><span style="color: #007700">{<br /> var </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /> var </span><span style="color: #0000BB">$dbtype </span><span style="color: #007700">= </span><span style="color: #DD0000">"mysql"</span><span style="color: #007700">;<br /><br /> function </span><span style="color: #0000BB">DBStorage</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">) <br /> {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data </span><span style="color: #007700">= </span><span style="color: #0000BB">$data</span><span style="color: #007700">;<br /> }<br /><br /> function </span><span style="color: #0000BB">save</span><span style="color: #007700">() <br /> {<br /> </span><span style="color: #0000BB">$dbh </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_connect</span><span style="color: #007700">();<br /> </span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #DD0000">"storage"</span><span style="color: #007700">, </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$serdata </span><span style="color: #007700">= </span><span style="color: #0000BB">serialize</span><span style="color: #007700">(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">data</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"insert into vars ('$serdata',now())"</span><span style="color: #007700">, </span><span style="color: #0000BB">$dbh</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">mysql_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">);<br /> }<br />}<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> <p class="para"> We then instantiate a couple of objects from the defined classes, and perform some aggregations and deaggregations, printing some object information along the way: </p> <p class="para"> <div class="example"> <p><b>Example #2 test_aggregation.php</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #007700">include </span><span style="color: #DD0000">"storageclasses.inc"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// some utilty functions<br /><br /></span><span style="color: #007700">function </span><span style="color: #0000BB">p_arr</span><span style="color: #007700">(</span><span style="color: #0000BB">$arr</span><span style="color: #007700">) <br />{<br /> foreach (</span><span style="color: #0000BB">$arr </span><span style="color: #007700">as </span><span style="color: #0000BB">$k </span><span style="color: #007700">=> </span><span style="color: #0000BB">$v</span><span style="color: #007700">)<br /> </span><span style="color: #0000BB">$out</span><span style="color: #007700">[] = </span><span style="color: #DD0000">"\t$k => $v"</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$out</span><span style="color: #007700">);<br />}<br /><br />function </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">) <br />{<br /> </span><span style="color: #0000BB">$out</span><span style="color: #007700">[] = </span><span style="color: #DD0000">"Class: " </span><span style="color: #007700">. </span><span style="color: #0000BB">get_class</span><span style="color: #007700">(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">);<br /> foreach (</span><span style="color: #0000BB">get_object_vars</span><span style="color: #007700">(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">) as </span><span style="color: #0000BB">$var</span><span style="color: #007700">=></span><span style="color: #0000BB">$val</span><span style="color: #007700">) {<br /> if (</span><span style="color: #0000BB">is_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$val</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">$out</span><span style="color: #007700">[] = </span><span style="color: #DD0000">"property: $var (array)\n" </span><span style="color: #007700">. </span><span style="color: #0000BB">p_arr</span><span style="color: #007700">(</span><span style="color: #0000BB">$val</span><span style="color: #007700">);<br /> } else {<br /> </span><span style="color: #0000BB">$out</span><span style="color: #007700">[] = </span><span style="color: #DD0000">"property: $var = $val"</span><span style="color: #007700">;<br /> }<br /> }<br /> foreach (</span><span style="color: #0000BB">get_class_methods</span><span style="color: #007700">(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">) as </span><span style="color: #0000BB">$method</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$out</span><span style="color: #007700">[] = </span><span style="color: #DD0000">"method: $method"</span><span style="color: #007700">;<br /> }<br /> return </span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$out</span><span style="color: #007700">);<br />}<br /><br /><br /></span><span style="color: #0000BB">$data </span><span style="color: #007700">= array(</span><span style="color: #0000BB">M_PI</span><span style="color: #007700">, </span><span style="color: #DD0000">"kludge != cruft"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// we create some basic objects<br /></span><span style="color: #0000BB">$fs </span><span style="color: #007700">= new </span><span style="color: #0000BB">FileStorage</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$ws </span><span style="color: #007700">= new </span><span style="color: #0000BB">WDDXStorage</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// print information on the objects<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"\$fs object\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"\n\$ws object\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$ws</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// do some aggregation<br /><br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">"\nLet's aggregate \$fs to the WDDXStorage class\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">aggregate</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">, </span><span style="color: #DD0000">"WDDXStorage"</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"\$fs object\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #DD0000">"\nNow let us aggregate it to the DBStorage class\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">aggregate</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">, </span><span style="color: #DD0000">"DBStorage"</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"\$fs object\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #DD0000">"\nAnd finally deaggregate WDDXStorage\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">deaggregate</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">, </span><span style="color: #DD0000">"WDDXStorage"</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"\$fs object\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">object_info</span><span style="color: #007700">(</span><span style="color: #0000BB">$fs</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> <p class="para"> We will now consider the output to understand some of the side-effects and limitation of object aggregation in PHP. First, the newly created <var class="varname">$fs</var> and <var class="varname">$ws</var> objects give the expected output (according to their respective class declaration). Note that for the purposes of object aggregation, <em class="emphasis">private elements of a class/object begin with an underscore character ("_")</em>, even though there is not real distinction between public and private class/object elements in PHP. </p> <p class="para"> <div class="informalexample"> <div class="example-contents"><div class="cdata"><pre>$fs objectClass: filestorageproperty: data (array) 0 => 3.1415926535898 1 => kludge != cruftmethod: filestoragemethod: write$ws objectClass: wddxstorageproperty: data (array) 0 => 3.1415926535898 1 => kludge != cruftproperty: version = 1.0property: _id = ID::9bb2b640764d4370eb04808af8b076a5method: wddxstoragemethod: storemethod: _genid</pre></div> </div> </div> </p> <p class="para"> We then aggregate <var class="varname">$fs</var> with the <b class="classname">WDDXStorage</b> class, and print out the object information. We can see now that even though nominally the <var class="varname">$fs</var> object is still of <b class="classname">FileStorage</b>, it now has the property <var class="varname">$version</var>, and the method <b>store()</b>, both defined in <b class="classname">WDDXStorage</b>. One important thing to note is that it has not aggregated the private elements defined in⌨️ 快捷键说明
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