Re: Freeing resources in closing tags
Interesting -- we got it working (must be magic!)... ;-) (Nevermind) -- Oliver Hans Bergsten wrote: Oliver Suciu wrote: In JSP 1.1, you simply cook your own try-catch-finally stuff, preferrably in a generic base tag, which all your concrete tags extend. Unfortunately that's not possible in JSP 1.1. If there's an exception while the custom action's body is processed, the page processing is aborted and the doEndTag() method is never called, just like Andrew said. Again, TryCatchFinally in JSP 1.2 was added specifically to address this problem. Hans Hans Bergsten wrote: Andrew Cooke wrote: Hi, I would like to use a Custom Tag to open resources in the start tag and free them in the closing tag. But if there is an exception in the enclosed body, it seems that I will leak the resource (as the closing tag will not be called). For example, if I open a database connection in doStartTag and fail to close it in doEndTag (because an exception was thrown) then I will have an open DB connection that is not returned to the pool. What is the best way to avoid this problem? This is exactly what the TryCatchFinally interface is for, added in JSP 1.2. For a JSP 1.1 container, I'm afraid there is no solution. Hans -- Hans Bergsten [EMAIL PROTECTED] Gefion Software http://www.gefionsoftware.com JavaServer Pageshttp://TheJSPBook.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com -- Hans Bergsten [EMAIL PROTECTED] Gefion Software http://www.gefionsoftware.com JavaServer Pageshttp://TheJSPBook.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com
Re: Freeing resources in closing tags
In JSP 1.1, you simply cook your own try-catch-finally stuff, preferrably in a generic base tag, which all your concrete tags extend. -- Oliver Hans Bergsten wrote: Andrew Cooke wrote: Hi, I would like to use a Custom Tag to open resources in the start tag and free them in the closing tag. But if there is an exception in the enclosed body, it seems that I will leak the resource (as the closing tag will not be called). For example, if I open a database connection in doStartTag and fail to close it in doEndTag (because an exception was thrown) then I will have an open DB connection that is not returned to the pool. What is the best way to avoid this problem? This is exactly what the TryCatchFinally interface is for, added in JSP 1.2. For a JSP 1.1 container, I'm afraid there is no solution. Hans -- Hans Bergsten [EMAIL PROTECTED] Gefion Software http://www.gefionsoftware.com JavaServer Pageshttp://TheJSPBook.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: signoff JSP-INTEREST. For digest: mailto [EMAIL PROTECTED] with body: set JSP-INTEREST DIGEST. Some relevant FAQs on JSP/Servlets can be found at: http://archives.java.sun.com/jsp-interest.html http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.jsp http://www.jguru.com/faq/index.jsp http://www.jspinsider.com
Custom tags: overloaded setters
Hi,
Can anybody help clarify how a JSP container should handle
overloaded setters in a custom tag:
public void setData(List dataList) {
this.dataList = dataList;
}
public void setData(Object dataObj) {
this.dataObj = dataObj;
}
public void setData(String dataStr) {
this.dataStr = dataStr;
}
We want to give the JSP author the convenience of passing data
to a tag using different types, whichever comes in more handy.
The data would be of the same logical kind, that's why, ideally,
the setters would bear the same name, just like overloaded methods
in Java.
As an example, JRun 3.1 accepts the code above, whereas Tomcat
3.2.3 throws a CompileException (Unable to convert a String
to java.util.List).
What's the correct behavior?
Thanks,
-- Oliver
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Re: Custom tags: overloaded setters
You're saying that the spec doesn't say anything about this;
how comes you then say that the behavior of Tomcat is the
correct one?...
Thx,
-- Oliver
Hans Bergsten wrote:
Oliver Suciu wrote:
Hi,
Can anybody help clarify how a JSP container should handle
overloaded setters in a custom tag:
public void setData(List dataList) {
this.dataList = dataList;
}
public void setData(Object dataObj) {
this.dataObj = dataObj;
}
public void setData(String dataStr) {
this.dataStr = dataStr;
}
We want to give the JSP author the convenience of passing data
to a tag using different types, whichever comes in more handy.
The data would be of the same logical kind, that's why, ideally,
the setters would bear the same name, just like overloaded methods
in Java.
As an example, JRun 3.1 accepts the code above, whereas Tomcat
3.2.3 throws a CompileException (Unable to convert a String
to java.util.List).
What's the correct behavior?
Tomcat's behavior is correct. When it comes to attribute setter
methods, a tag handler class is a bean, so you must go to the
bean spec to see how it deals with property setter methods.
The spec text itself doesn't say anything about multiple setter
methods, but the implementation of the methods that deal with
setter methods only allow one setter method per property. Hence,
multiple setter methods for a tag handler attribute is not
allowed.
In JSP 1.2 you can get around this by making the type of the
attribute Object, and the figure out which specific type you
got. The reason this only works well with JSP 1.2 is that
JSP 1.1 doesn't accept a string literal as the attribute
value for an attribute of type Object; JSP 1.2 does.
public void setData(Object data) {
this.data = data;
}
public int doStartTag() {
if (data instanceof List) {
// Work with it as a List
}
else (data.getClass().isArray()) {
// Work with it as an array
}
else (data instanceof String) {
// Work with as a String
}
else ...
}
I describe this in more detail in an article that will soon
be published at the O'Reilly site. I'll post the URL here
when it's available.
Hans
--
Hans Bergsten [EMAIL PROTECTED]
Gefion Software http://www.gefionsoftware.com
Author of JavaServer Pages (O'Reilly), http://TheJSPBook.com
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Packaging Precompiled JSP?
Hi,
JSP 1.1 (and 1.2) specify a way to precompile your pages
and package them as a bunch of Java .class files (eg, in
a WAR file).
However, the spec allows for "implementation dependent"
names in the compiled code -- so the question is, what
else do you need to package in order for your compiled
pages to work?
Eg, JRun 3.0 creates something like this:
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import allaire.jrun.jsp.JRunJSPStaticHelpers;
public class jrun__html__MainPage2ejsp12
extends allaire.jrun.jsp.HttpJSPServlet
implements allaire.jrun.jsp.JRunJspPage {
...
}
...so there is dependency on classes provided by Allaire,
which I would have to include in the WAR file (if I wanted
to make sure that they work not only with JRun)...
Does anybody have any experience with this?
Is there maybe a JSP compiler that creates independent
code, or that allows you to include its support classes
in your package? (Maybe Tomcat?)
Any hint is much appreciated.
Thanks a lot,
-- Oliver
--
Oliver Suciu
[EMAIL PROTECTED]
http://www.tibcofinance.com
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Re: MessageDigest and the database
Make it a string: new String(byte[] buf) -- Oliver "Hernandez, Rey" wrote: Hi all, How are people using the MessageDigest object to encrypt values before sending them to the database? Maybe I'm using it in the wrong way, but I am trying to do something like this: Get a value from the user, across SSL, like a password. Encrypt that password with MessageDigest(using MD5). Put the resulting byte array into the database. I can't seem to find a way to get a byte array into the database, Oracle in this case. I figured I could use a NUMBER datatype, but then how do you convert a byte array to a java datatype that you can use with one of the setXXX functions provided with PreparedStatement that will go into a NUMBER? Hope I didn't confuse everyone with this question, I'd be happy to clarify. Thanks in advance, Rey === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". Some relevant FAQs on JSP/Servlets can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets -- Oliver Suciu [EMAIL PROTECTED] http://www.tibcofinance.com === To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST". Some relevant FAQs on JSP/Servlets can be found at: http://java.sun.com/products/jsp/faq.html http://www.esperanto.org.nz/jsp/jspfaq.html http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
Re: Object attributes for custom tags
Yes -- if you fix it to %=v%... ;-)
-- Oliver
Dan Cancro wrote:
Can you pass objects other than strings as attributes to a custom tag? I'm
thinking of something that would look something like this:
%
Vector v = new Vector();
v.addElement("asdfasdf");
%
myTagLib:testObjectAttribute Vector=%v%/
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--
Oliver Suciu
[EMAIL PROTECTED]
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