<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Object Interfaces</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="类与对象(PHP 5)" HREF="language.oop5.html"><LINK REL="PREVIOUS" TITLE="Class Abstraction" HREF="language.oop5.abstract.html"><LINK REL="NEXT" TITLE="Overloading" HREF="language.oop5.overloading.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></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" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="language.oop5.abstract.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >章 19. 类与对象(PHP 5)</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="language.oop5.overloading.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="language.oop5.interfaces" >Object Interfaces</A ></H1 ><P > Object interfaces allow you to create code which specifies which methods a class must implement, without having to define how these methods are handled. </P ><P > Interfaces are defined using the interface keyword, in the same way as a standard class, but without any of the methods having their contents defined. </P ><P > All methods declared in an interface must be public, this is the nature of an interface. </P ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN5872" ><TT CLASS="literal" >implements</TT ></A ></H2 ><P > To implement an interface, the <TT CLASS="literal" >implements</TT > operator is used. All methods in the interface must be implemented within a class; failure to do so will result in a fatal error. Classes may implement more than one interface if desired by separating each interface with a comma. </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >注意: </B > A class cannot implement two interfaces that share function names, since it would cause ambiguity. </P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN5879" >范例</A ></H2 ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN5881" ></A ><P ><B >例 19-19. Interface example</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /></font><font color="#FF8000">// Declare the interface 'iTemplate'<br /></font><font color="#0000BB">interface iTemplate<br /></font><font color="#007700">{<br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">setVariable</font><font color="#007700">(</font><font color="#0000BB">$name</font><font color="#007700">, </font><font color="#0000BB">$var</font><font color="#007700">);<br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">getHtml</font><font color="#007700">(</font><font color="#0000BB">$template</font><font color="#007700">);<br />}<br /><br /></font><font color="#FF8000">// Implement the interface<br />// This will work<br /></font><font color="#007700">class </font><font color="#0000BB">Template implements iTemplate<br /></font><font color="#007700">{<br /> </font><font color="#0000BB">private $vars </font><font color="#007700">= array();<br /> <br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">setVariable</font><font color="#007700">(</font><font color="#0000BB">$name</font><font color="#007700">, </font><font color="#0000BB">$var</font><font color="#007700">)<br /> {<br /> </font><font color="#0000BB">$this</font><font color="#007700">-></font><font color="#0000BB">vars</font><font color="#007700">[</font><font color="#0000BB">$name</font><font color="#007700">] = </font><font color="#0000BB">$var</font><font color="#007700">;<br /> }<br /> <br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">getHtml</font><font color="#007700">(</font><font color="#0000BB">$template</font><font color="#007700">)<br /> {<br /> foreach(</font><font color="#0000BB">$this</font><font color="#007700">-></font><font color="#0000BB">vars </font><font color="#007700">as </font><font color="#0000BB">$name </font><font color="#007700">=> </font><font color="#0000BB">$value</font><font color="#007700">) {<br /> </font><font color="#0000BB">$template </font><font color="#007700">= </font><font color="#0000BB">str_replace</font><font color="#007700">(</font><font color="#DD0000">'{' </font><font color="#007700">. </font><font color="#0000BB">$name </font><font color="#007700">. </font><font color="#DD0000">'}'</font><font color="#007700">, </font><font color="#0000BB">$value</font><font color="#007700">, </font><font color="#0000BB">$template</font><font color="#007700">);<br /> }<br /> <br /> return </font><font color="#0000BB">$template</font><font color="#007700">;<br /> }<br />}<br /><br /></font><font color="#FF8000">// This will not work<br />// Fatal error: Class BadTemplate contains 1 abstract methods<br />// and must therefore be declared abstract (iTemplate::getHtml)<br /></font><font color="#007700">class </font><font color="#0000BB">BadTemplate implements iTemplate<br /></font><font color="#007700">{<br /> </font><font color="#0000BB">private $vars </font><font color="#007700">= array();<br /> <br /> </font><font color="#0000BB">public </font><font color="#007700">function </font><font color="#0000BB">setVariable</font><font color="#007700">(</font><font color="#0000BB">$name</font><font color="#007700">, </font><font color="#0000BB">$var</font><font color="#007700">)<br /> {<br /> </font><font color="#0000BB">$this</font><font color="#007700">-></font><font color="#0000BB">vars</font><font color="#007700">[</font><font color="#0000BB">$name</font><font color="#007700">] = </font><font color="#0000BB">$var</font><font color="#007700">;<br /> }<br />}<br /><br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P > See also the <A HREF="language.operators.type.html" >instanceof</A > operator. </P ></DIV ></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.abstract.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="language.oop5.overloading.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Class Abstraction</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="language.oop5.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Overloading</TD ></TR ></TABLE ></DIV ></BODY ></HTML >