<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Introduction</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="book.objaggregation.html">Object Aggregation</a></div> <div class="next" style="text-align: right; float: right;"><a href="objaggregation.examples.html">Examples</a></div> <div class="up"><a href="book.objaggregation.html">Object Aggregation</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="intro.objaggregation" class="preface"> <h1 class="title">Introduction</h1> <div class="warning"><strong class="warning">Warning</strong><p class="simpara">This extension is <em class="emphasis">EXPERIMENTAL</em>. The behaviour of this extension including the names of its functions and any other documentation surrounding this extension may change without notice in a future release of PHP. This extension should be used at your own risk.</p></div> <p class="para"> In Object Oriented Programming, it is common to see the composition of simple classes (and/or instances) into a more complex one. This is a flexible strategy for building complicated objects and object hierarchies and can function as a dynamic alternative to multiple inheritance. There are two ways to perform class (and/or object) composition depending on the relationship between the composed elements: <em class="emphasis">Association</em> and <em class="emphasis">Aggregation</em>. </p> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="book.objaggregation.html">Object Aggregation</a></div> <div class="next" style="text-align: right; float: right;"><a href="objaggregation.examples.html">Examples</a></div> <div class="up"><a href="book.objaggregation.html">Object Aggregation</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>