📄 looptagsupport.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><!--NewPage--><HTML><HEAD><!-- Generated by javadoc (build 1.4.2_05) on Mon Oct 25 13:31:38 PDT 2004 --><TITLE>LoopTagSupport</TITLE><META NAME="keywords" CONTENT="javax.servlet.jsp.jstl.core.LoopTagSupport class"><LINK REL ="stylesheet" TYPE="text/css" HREF="../../../../../stylesheet.css" TITLE="Style"><SCRIPT type="text/javascript">function windowTitle(){ parent.document.title="LoopTagSupport";}</SCRIPT></HEAD><BODY BGCOLOR="white" onload="windowTitle();"><!-- ========= START OF TOP NAVBAR ======= --><A NAME="navbar_top"><!-- --></A><A HREF="#skip-navbar_top" title="Skip navigation links"></A><TABLE BORDER="0" WIDTH="100%" CELLPADDING="1" CELLSPACING="0" SUMMARY=""><TR><TD COLSPAN=3 BGCOLOR="#EEEEFF" CLASS="NavBarCell1"><A NAME="navbar_top_firstrow"><!-- --></A><TABLE BORDER="0" CELLPADDING="0" CELLSPACING="3" SUMMARY=""> <TR ALIGN="center" VALIGN="top"> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../overview-summary.html"><FONT CLASS="NavBarFont1"><B>Overview</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-summary.html"><FONT CLASS="NavBarFont1"><B>Package</B></FONT></A> </TD> <TD BGCOLOR="#FFFFFF" CLASS="NavBarCell1Rev"> <FONT CLASS="NavBarFont1Rev"><B>Class</B></FONT> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="package-tree.html"><FONT CLASS="NavBarFont1"><B>Tree</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../deprecated-list.html"><FONT CLASS="NavBarFont1"><B>Deprecated</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../index-all.html"><FONT CLASS="NavBarFont1"><B>Index</B></FONT></A> </TD> <TD BGCOLOR="#EEEEFF" CLASS="NavBarCell1"> <A HREF="../../../../../help-doc.html"><FONT CLASS="NavBarFont1"><B>Help</B></FONT></A> </TD> </TR></TABLE></TD><TD ALIGN="right" VALIGN="top" ROWSPAN=3><EM></EM></TD></TR><TR><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../javax/servlet/jsp/jstl/core/Config.html" title="class in javax.servlet.jsp.jstl.core"><B>PREV CLASS</B></A> NEXT CLASS</FONT></TD><TD BGCOLOR="white" CLASS="NavBarCell2"><FONT SIZE="-2"> <A HREF="../../../../../index.html" target="_top"><B>FRAMES</B></A> <A HREF="LoopTagSupport.html" target="_top"><B>NO FRAMES</B></A> <SCRIPT type="text/javascript"> <!-- if(window==top) { document.writeln('<A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A>'); } //--></SCRIPT><NOSCRIPT> <A HREF="../../../../../allclasses-noframe.html"><B>All Classes</B></A></NOSCRIPT></FONT></TD></TR><TR><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2"> SUMMARY: NESTED | <A HREF="#field_summary">FIELD</A> | <A HREF="#constructor_summary">CONSTR</A> | <A HREF="#method_summary">METHOD</A></FONT></TD><TD VALIGN="top" CLASS="NavBarCell3"><FONT SIZE="-2">DETAIL: <A HREF="#field_detail">FIELD</A> | <A HREF="#constructor_detail">CONSTR</A> | <A HREF="#method_detail">METHOD</A></FONT></TD></TR></TABLE><A NAME="skip-navbar_top"></A><!-- ========= END OF TOP NAVBAR ========= --><HR><!-- ======== START OF CLASS DATA ======== --><H2><FONT SIZE="-1">javax.servlet.jsp.jstl.core</FONT><BR>Class LoopTagSupport</H2><PRE>java.lang.Object <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by">javax.servlet.jsp.tagext.TagSupport <IMG SRC="../../../../../resources/inherit.gif" ALT="extended by"><B>javax.servlet.jsp.jstl.core.LoopTagSupport</B></PRE><DL><DT><B>All Implemented Interfaces:</B> <DD>javax.servlet.jsp.tagext.IterationTag, javax.servlet.jsp.tagext.JspTag, <A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTag.html" title="interface in javax.servlet.jsp.jstl.core">LoopTag</A>, java.io.Serializable, javax.servlet.jsp.tagext.Tag, javax.servlet.jsp.tagext.TryCatchFinally</DD></DL><HR><DL><DT>public abstract class <B>LoopTagSupport</B><DT>extends javax.servlet.jsp.tagext.TagSupport<DT>implements <A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTag.html" title="interface in javax.servlet.jsp.jstl.core">LoopTag</A>, javax.servlet.jsp.tagext.IterationTag, javax.servlet.jsp.tagext.TryCatchFinally</DL><P><p>Base support class to facilitate implementation of iteration tags.</p> <p>Since most iteration tags will behave identically with respect to actual iterative behavior, JSTL provides this base support class to facilitate implementation. Many iteration tags will extend this and merely implement the <tt>hasNext()</tt> and <tt>next()</tt> methods to provide contents for the handler to iterate over.</p> <p>In particular, this base class provides support for:</p> <ul> <li> Iteration control, based on protected <tt>prepare()</tt>, <tt>next()</tt>, and <tt>hasNext()</tt> methods <li> Subsetting (<tt>begin</tt>, <tt>end</tt>, <tt>step></tt>functionality, including validation of subset parameters for sensibility) <li> item retrieval (<tt>getCurrent()</tt>) <li> status retrieval (<tt>LoopTagStatus</tt>) <li> exposing attributes (set by <tt>var</tt> and <tt>varStatus</tt> attributes) </ul> <p>In providing support for these tasks, <tt>LoopTagSupport</tt> contains certain control variables that act to modify the iteration. Accessors are provided for these control variables when the variables represent information needed or wanted at translation time (e.g., <tt>var</tt>, <tt>varStatus</tt>). For other variables, accessors cannot be provided here since subclasses may differ on their implementations of how those accessors are received. For instance, one subclass might accept a <tt>String</tt> and convert it into an object of a specific type by using an expression evaluator; others might accept objects directly. Still others might not want to expose such information to outside control.</p><P><P><DL><DT><B>Author:</B></DT> <DD>Shawn Bayern</DD><DT><B>See Also:</B><DD><A HREF="../../../../../serialized-form.html#javax.servlet.jsp.jstl.core.LoopTagSupport">Serialized Form</A></DL><HR><P><!-- ======== NESTED CLASS SUMMARY ======== --><!-- =========== FIELD SUMMARY =========== --><A NAME="field_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Field Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#begin">begin</A></B></CODE><BR> Starting index ('begin' attribute)</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#beginSpecified">beginSpecified</A></B></CODE><BR> Boolean flag indicating whether 'begin' was specified.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#end">end</A></B></CODE><BR> Ending index of the iteration ('end' attribute).</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#endSpecified">endSpecified</A></B></CODE><BR> Boolean flag indicating whether 'end' was specified.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#itemId">itemId</A></B></CODE><BR> Attribute-exposing control</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected java.lang.String</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#statusId">statusId</A></B></CODE><BR> Attribute-exposing control</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#step">step</A></B></CODE><BR> Iteration step ('step' attribute)</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE>protected boolean</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#stepSpecified">stepSpecified</A></B></CODE><BR> Boolean flag indicating whether 'step' was specified.</TD></TR></TABLE> <A NAME="fields_inherited_from_class_javax.servlet.jsp.tagext.TagSupport"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TD><B>Fields inherited from class javax.servlet.jsp.tagext.TagSupport</B></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE>id, pageContext</CODE></TD></TR></TABLE> <A NAME="fields_inherited_from_class_javax.servlet.jsp.tagext.Tag"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TD><B>Fields inherited from interface javax.servlet.jsp.tagext.Tag</B></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE>EVAL_BODY_INCLUDE, EVAL_PAGE, SKIP_BODY, SKIP_PAGE</CODE></TD></TR></TABLE> <A NAME="fields_inherited_from_class_javax.servlet.jsp.tagext.IterationTag"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor"><TD><B>Fields inherited from interface javax.servlet.jsp.tagext.IterationTag</B></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE>EVAL_BODY_AGAIN</CODE></TD></TR></TABLE> <!-- ======== CONSTRUCTOR SUMMARY ======== --><A NAME="constructor_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Constructor Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#LoopTagSupport()">LoopTagSupport</A></B>()</CODE><BR> Constructs a new LoopTagSupport.</TD></TR></TABLE> <!-- ========== METHOD SUMMARY =========== --><A NAME="method_summary"><!-- --></A><TABLE BORDER="1" WIDTH="100%" CELLPADDING="3" CELLSPACING="0" SUMMARY=""><TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor"><TD COLSPAN=2><FONT SIZE="+2"><B>Method Summary</B></FONT></TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#doAfterBody()">doAfterBody</A></B>()</CODE><BR> Continues the iteration when appropriate -- that is, if we (a) have more items and (b) don't run over our 'end' (given our 'step').</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#doCatch(java.lang.Throwable)">doCatch</A></B>(java.lang.Throwable t)</CODE><BR> Rethrows the given Throwable.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> void</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#doFinally()">doFinally</A></B>()</CODE><BR> Removes any attributes that this LoopTagSupport set.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> int</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#doStartTag()">doStartTag</A></B>()</CODE><BR> Begins iterating by processing the first item.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor"><TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1"><CODE> java.lang.Object</CODE></FONT></TD><TD><CODE><B><A HREF="../../../../../javax/servlet/jsp/jstl/core/LoopTagSupport.html#getCurrent()">getCurrent</A></B>()</CODE><BR> Retrieves the current item in the iteration.</TD></TR><TR BGCOLOR="white" CLASS="TableRowColor">⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -