web/faq.html - tapestry4 - Git at Google

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 		<td valign="top" align="left"><IMG height=44 alt="[Tapestry Logo]" src ="images/ico_t.gif" width=44 align=absMiddle border=0 >&nbsp;<IMG height=22 alt=Tapestry src="images/hd_tapestry.gif" width=100 align=absMiddle vspace=17 border=0>

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 		<td><b>How does Tapestry compare to other frameworks?</b>

 		<br><br>

 		Tapestry is very much unlike most other frameworks in that it doesn't use
 code generation; instead it uses a true component object model based
 on JavaBeans properties and strong specifications.  This gives Tapestry a huge
 amount of flexibility and enables dynamic runtime inspection of the application
 with the Tapestry Inspector (a mini-application that can be built into any Tapestry
 application).

 <p>In addition, Tapestry applications require
             far less Java coding and are far more robust than equivalent
             applications developed with other popular frameworks. This is
             because the Tapestry framework takes responsibility for many
             important tasks, such as maintaining server-side state and
             dispatching incoming requests to appropriate objects and methods.</p>


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 	</tr>

 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td><b>How is the performance of Tapestry?</b>

 		<br><br>

 		My own testing, documented in the Sept. 2001 issue of the Java Report,
 	agrees with other testing (documented in the Tapestry discussion forums):
 	Although straight JSPs have a slight edge in demo applications, in
 	real applications with a database or application server backend, the performance
 	curves for equivalent Tapestry and JSP applications are identical.

 	<p>Don't think about the performance of
             Tapestry; think about the performance of your Java developers.</p>


 		</td>
 	</tr>

 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td>
             <P><b>Is Tapestry a JSP tag library?</b>

 		<br><br>

 	Tapestry is
             <STRONG>not </STRONG>a JSP tag library; Tapestry builds on the
             servlet API, but doesn't use JSPs in any way.&nbsp; It uses it own
             HTML template format and its own rendering engine.</P>
             <P>In the current release, 2.2, Tapestry does not interoperate with
             JSP pages ... its a whole, seperate world.</P>
             <P>This has proven to be a big sticking point in adoption of
             Tapestry.&nbsp; In the next release, 2.3, Tapestry will finally get
             JSP interoperation.&nbsp; You'll be able to represent a Tapestry
             component inside a JSP as a JSP tag, but still use everything good
             and bad about JSPs, including other taglibs and even Java
             scriplets.</P>


 		</td>
 	</tr>


 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td><b>What does it cost?</b>

 		<br><br>

 		Tapestry is open source and free.  It is licensed
 	under the Apache Software License, which allows
 	it to be used even inside proprietary software.

 		</td>
 	</tr>

 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td><b>Is there a WYSIWYG editor for Tapestry, or an IDE plugin?</b>

 		<br><br>

 		Currently, no WYSIWYG editor is available for Tapestry; however, the design of Tapestry
 	allows existing editors to work reasonably well (Tapestry additions to the HTML markup
 	are virtually invisible to a WYSIWYG editor).

 <p><a target="top" href="http://sf.net/projects/spindle">Spindle</a>
 is a Tapestry plugin
 	for the excellent open-source <a href="http://www.eclipse.org">Eclipse</a> IDE. It adds wizards and editors
             for creating Tapestry applications, pages and components.</p>


 		</td>
 	</tr>

 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td><b>I have to restart my application to pick up changes to specifications and templates, how
 		can I avoid this?</b>

 		<br><br>

 Start your servlet container with the JVM system parameter
 <code>net.sf.tapestry.disable-caching</code> set to true, i.e.,
 <code>-Dnet.sf.tapestry.disable-caching=true</code>.

 <p>Tapestry will discard cached specifications
             and templates after each request. You application will run a bit
             slower, but changes to templates and specifications will show up
             immediately. This also tests that you are persisting server-side
             state correctly.</p>


 		</td>
 	</tr>

 	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

 	<tr valign="top">
 		<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
 		<td><b>I  keep getting <A href="doc/api/net/sf/tapestry/StaleSessionException.html">StaleSessionException</a>s
 		from links and forms.
 		</b>

 		<br><br>

 		Tapestry doesn't create a <code>HttpSession</code> until you have server-side state to store.  Most applications
 		don't start to store server-side state until after the Home page.

 		<p>
 		By default,
 		<A href="doc/ComponentReference/ActionLink.html">ActionLink</a>,
 		<A href="doc/ComponentReference/DirectLink.html">DirectLink</a> and
 		<A href="doc/ComponentReference/Form.html">Form</a> require
             that
 		a session be already created (this is
 		primarily to handle the case where a user walks away from their computer and returns, and the
 		 servlet container has discarded the HttpSession in the meantime).
 		 Set the stateful parameter to false (i.e.,
 		 <code>&lt;binding name="stateful" expression="false"/&gt;</code>) to disable this check.</p>


 		</td>
 	</tr>


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	<!doctype html public "-//W3C//DTD HTML 4.0 Transitional//EN">
	<html>
	<head>
	<title>Tapestry: FAQ</title><link rel="STYLESHEET" type="text/css" href="scripts/style_virtlib_pcIE55.css">
	</head>
	<body bgcolor="#839cd1" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
	<table width="100%" border="0" cellspacing="0" cellpadding="2">
	<tr>
	<td valign="top" align="left"><IMG height=44 alt="[Tapestry Logo]" src ="images/ico_t.gif" width=44 align=absMiddle border=0 > <IMG height=22 alt=Tapestry src="images/hd_tapestry.gif" width=100 align=absMiddle vspace=17 border=0>

	<br><br>

	<table border="0" cellspacing="0" cellpadding="2">
	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>How does Tapestry compare to other frameworks?</b>

	<br><br>

	Tapestry is very much unlike most other frameworks in that it doesn't use
	code generation; instead it uses a true component object model based
	on JavaBeans properties and strong specifications. This gives Tapestry a huge
	amount of flexibility and enables dynamic runtime inspection of the application
	with the Tapestry Inspector (a mini-application that can be built into any Tapestry
	application).

	<p>In addition, Tapestry applications require
	far less Java coding and are far more robust than equivalent
	applications developed with other popular frameworks. This is
	because the Tapestry framework takes responsibility for many
	important tasks, such as maintaining server-side state and
	dispatching incoming requests to appropriate objects and methods.</p>





	</td>
	</tr>

	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>How is the performance of Tapestry?</b>

	<br><br>

	My own testing, documented in the Sept. 2001 issue of the Java Report,
	agrees with other testing (documented in the Tapestry discussion forums):
	Although straight JSPs have a slight edge in demo applications, in
	real applications with a database or application server backend, the performance
	curves for equivalent Tapestry and JSP applications are identical.

	<p>Don't think about the performance of
	Tapestry; think about the performance of your Java developers.</p>


	</td>
	</tr>

	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td>
	<P><b>Is Tapestry a JSP tag library?</b>

	<br><br>

	Tapestry is
	<STRONG>not </STRONG>a JSP tag library; Tapestry builds on the
	servlet API, but doesn't use JSPs in any way.  It uses it own
	HTML template format and its own rendering engine.</P>
	<P>In the current release, 2.2, Tapestry does not interoperate with
	JSP pages ... its a whole, seperate world.</P>
	<P>This has proven to be a big sticking point in adoption of
	Tapestry.  In the next release, 2.3, Tapestry will finally get
	JSP interoperation.  You'll be able to represent a Tapestry
	component inside a JSP as a JSP tag, but still use everything good
	and bad about JSPs, including other taglibs and even Java
	scriplets.</P>






	</td>
	</tr>




	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>What does it cost?</b>

	<br><br>

	Tapestry is open source and free. It is licensed
	under the Apache Software License, which allows
	it to be used even inside proprietary software.

	</td>
	</tr>

	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>Is there a WYSIWYG editor for Tapestry, or an IDE plugin?</b>

	<br><br>

	Currently, no WYSIWYG editor is available for Tapestry; however, the design of Tapestry
	allows existing editors to work reasonably well (Tapestry additions to the HTML markup
	are virtually invisible to a WYSIWYG editor).

	<p><a target="top" href="http://sf.net/projects/spindle">Spindle</a>
	is a Tapestry plugin
	for the excellent open-source <a href="http://www.eclipse.org">Eclipse</a> IDE. It adds wizards and editors
	for creating Tapestry applications, pages and components.</p>


	</td>
	</tr>

	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>I have to restart my application to pick up changes to specifications and templates, how
	can I avoid this?</b>

	<br><br>

	Start your servlet container with the JVM system parameter
	<code>net.sf.tapestry.disable-caching</code> set to true, i.e.,
	<code>-Dnet.sf.tapestry.disable-caching=true</code>.

	<p>Tapestry will discard cached specifications
	and templates after each request. You application will run a bit
	slower, but changes to templates and specifications will show up
	immediately. This also tests that you are persisting server-side
	state correctly.</p>





	</td>
	</tr>

	<tr><td height="10"><IMG src="images/spacer.gif" width=1></td></tr>

	<tr valign="top">
	<td><IMG height=12 src="images/dots_leftnav.gif" width=14></td>
	<td><b>I keep getting <A href="doc/api/net/sf/tapestry/StaleSessionException.html">StaleSessionException</a>s
	from links and forms.
	</b>

	<br><br>

	Tapestry doesn't create a <code>HttpSession</code> until you have server-side state to store. Most applications
	don't start to store server-side state until after the Home page.

	<p>
	By default,
	<A href="doc/ComponentReference/ActionLink.html">ActionLink</a>,
	<A href="doc/ComponentReference/DirectLink.html">DirectLink</a> and
	<A href="doc/ComponentReference/Form.html">Form</a> require
	that
	a session be already created (this is
	primarily to handle the case where a user walks away from their computer and returns, and the
	servlet container has discarded the HttpSession in the meantime).
	Set the stateful parameter to false (i.e.,
	<code><binding name="stateful" expression="false"/></code>) to disable this check.</p>




	</td>
	</tr>





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	<table width="100%" border="0" cellspacing="0" cellpadding="0">
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	<td>
	</td>
	</tr>
	<tr bgcolor="#4b5887">
	<td height="47">
	<IMG src="images/spacer.gif">
	</td>
	</tr>
	<tr bgcolor="#333333">
	<td height="65">
	<table width="724" border="0" cellspacing="0" cellpadding="3" bgcolor="#000000">
	<tr height="65">
	<td width="654" align="right" valign="bottom" class="clsFooter">© 2003 Apache Software Foundation.
	All rights reserved.
	</td>
	<td width="70">
	</td>
	</tr>
	</table>
	</td>
	</tr>
	<tr bgcolor="#333333">
	<td>
	<table width="724" border="0" cellspacing="0" cellpadding="3" bgcolor="#000000">
	<tr height="65">
	<td height="200" width="654">
	</td>
	<td width="70">
	</td>
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