<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <HTML ><HEAD ><TITLE >Object Abstraction</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Manual PHP" HREF="index.html"><LINK REL="UP" TITLE="Classes and Objects (PHP 5)" HREF="language.oop5.html"><LINK REL="PREVIOUS" TITLE="Object Constants" HREF="language.oop5.constants.html"><LINK REL="NEXT" TITLE="Object Interfaces" HREF="language.oop5.interfaces.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=ISO-8859-2"></HEAD ><BODY CLASS="sect1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Manual PHP</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="language.oop5.constants.html" ACCESSKEY="P" >Înapoi</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Cap. 14. Classes and Objects (PHP 5)</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="language.oop5.interfaces.html" ACCESSKEY="N" >Înainte</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="language.oop5.abstract" >Object Abstraction</A ></H1 ><P > PHP 5 introduces abstract classes and methods. An abstract method only declares the method's signature and does not provide an implementation. A class that contains abstract methods needs to be declared abstract. </P ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN3397" ></A ><P ><B >Exemplu 14-4. </B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />abstract </font><font color="#007700">class </font><font color="#0000BB">AbstractClass </font><font color="#007700">{<br /> </font><font color="#0000BB">abstract public </font><font color="#007700">function </font><font color="#0000BB">test</font><font color="#007700">();<br />}<br /><br />class </font><font color="#0000BB">ImplementedClass </font><font color="#007700">extends </font><font color="#0000BB">AbstractClass </font><font color="#007700">{<br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">test</font><font color="#007700">() {<br /> echo </font><font color="#DD0000">"ImplementedClass::test() called.\n"</font><font color="#007700">;<br /> }<br />}<br /><br /></font><font color="#0000BB">$o </font><font color="#007700">= new </font><font color="#0000BB">ImplementedClass</font><font color="#007700">;<br /></font><font color="#0000BB">$o</font><font color="#007700">-></font><font color="#0000BB">test</font><font color="#007700">();<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P > Abstract classes cannot be instantiated. Old code that has no user-defined classes or functions named 'abstract' should run without modifications. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="language.oop5.constants.html" ACCESSKEY="P" >Înapoi</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Acasã</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="language.oop5.interfaces.html" ACCESSKEY="N" >Înainte</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Object Constants</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="language.oop5.html" ACCESSKEY="U" >Sus</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Object Interfaces</TD ></TR ></TABLE ></DIV ></BODY ></HTML >