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Object as a parameter

Greenhorn

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posted 14 years ago

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Hallo,
Here is my JSF page. I try to send current HyperlinkBean Object to HyperlinkVerwalterObject.
It will be saved in that class. The class has a method which accepts HyperlinkBean as a parameter.

How is it possible? I didn't find any way to solve it..

Method in HyperlinkVerwalter:

JSF Page :

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
	xmlns:f="http://java.sun.com/jsf/core"
	xmlns:h="http://java.sun.com/jsf/html">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Hyperlink Exercise</title>
</head>
<body>
<h:form>
	<h2>JSF Registration App</h2>
	<h4>New Hyperlink</h4>
	<table>
 		<tr>
 			<td>Name:</td>
 			<td><h:inputText value="#{HyperlinkBean.name}" required="true"
 				id="name" /> <h:message for="name" /></td>
 		</tr>
 		<tr>
 			<td>URL:</td>
 			<td><h:inputText value="#{HyperlinkBean.url}" required="true"
 				id="url" /> <h:message for="url" /></td>
 		</tr>
 
 	</table>
	<p><h:commandButton value="OK"
		action="#{HyperlinkVerwalter.addHyperlink}">
		<f:param name="bean" value="{HyperlinkBean}" />

</h:commandButton> <h:commandButton value="Cancel" action="/faces/hyperlink.jsp" /></p>
</h:form>
</body>
</html>

SCJP

Tim Holloway

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posted 14 years ago

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A JSF View is (normally) rendered as HTML. HTML is a text-only format (no binary information). Objects are binary constructs.

That means that to pass an object on a web page (HTML View), you'd have to convert the object to text format as part of the page rendering process and convert the text representation of the object back to binary form when the page is submitted. And as a bonus, it won't actually be the same object as what you started with (so the "==" test fails).

Actually, in addition to the trouble and overhead, passing internal objects back and forth across web pages makes for a very insecure webapp, since a hacker can tinker with the object while it's on the client side.

More commonly, one would pass the identifier of an object and use that to reference the original object back on the server. Session-scope objects work that way, for example.

Education won't help those who are proudly and willfully ignorant. They'll literally rather die before changing.