yes! a related bug is that comparing items of two different classes gives
an error (doesn't even return false).
I think if both items are numbers the comparison should be numeric, of
course. (integer 2 == double 2.0 even though the string representations are
different). Otherwise, it'd be nice to compare on Strings.
Is this in bugzilla? cough... I mean JIRA? It's a pretty easy fix.
(ASTEquals if I remember from memory). Can we get away with this for the
1.5 release or is that a backwards compatibility issue? (1.5 *must* stay
backwards compatible). My first reaction is that this is ok. (since this
wasn't even valid VTL before).
WILL
----- Original Message -----
From: "Nathan Bubna" <[EMAIL PROTECTED]>
To: "Velocity Users List" <velocity-user@jakarta.apache.org>;
<[EMAIL PROTECTED]>
Sent: Friday, September 16, 2005 2:09 PM
Subject: Re: Comparing strings
All good discussion, Henning is, of course, right on.
but all this reminds me of a closely related velocity wish-list item
of mine: having == comparisons be done on the *rendered* value of the
references, rather than the class value. in other words, i would
like:
#set( $two = 2 )
#if( $two == '2' )
to output this text!
#end
after all, putting "$two equals 2" in a template (leave off the #if)
and rendering it will output "2 equals 2". why shouldn't things that
will be rendered identically by VTL be treated as equal in #if
statements? i think that is the most intuitive way to do comparisons
in a template language where the focus is on the rendered output.
perhaps it's time i put a page on the wiki for it, to perhaps build a
little momentum/consensus for getting this in future versions.
On 9/16/05, Henning P. Schmiedehausen <[EMAIL PROTECTED]> wrote:
"Steve O'Hara" <[EMAIL PROTECTED]> writes:
>A while back I chastised someone for not using proper String comparison
>operators in their templates. I looked in the Velocity code and sure
>enough "==" operators are translated into equals. So I was looking a bit
>stupid.
>Somebody challenged me to come up with a situation where the equality
>"==" operator doesn't work with Strings.
>Well, finally, I've just found an example in my code;
> #if ($SummarySortField==$Field.getUdmFieldName())
> #if ($SummarySortField==${Field.getUdmFieldName()})
> #if ($SummarySortField.equalsIgnoreCase($Field.getUdmFieldName()))
>I thought perhaps I was going mad before when I raised this and plenty
>of people on this list questioned me, but can anyone explain this?
equalsIngoreCase != equals.
In Java, equals != ==
Look at this:
public class Test {
public static void main(String [] argv) throws Exception {
String s1 = "foo";
String s2 = "foobar".substring(0,3);
System.out.println(s1);
System.out.println(s2);
System.out.println(s1 == s2);
System.out.println(s1.equals(s2));
}
}
outputs
foo
foo
false
true
However, in Velocity:
--- cut ---
import java.io.OutputStreamWriter;
import org.apache.commons.lang.ObjectUtils;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
public class Demo {
public static void main(String[] args) {
try {
Velocity.init();
VelocityContext vc = new VelocityContext();
String s1 = "foo";
String s2 = "foobar".substring(0,3);
vc.put("s1", s1);
vc.put("s2", s2);
vc.put("s1info", ObjectUtils.appendIdentityToString(null,
s1).toString());
vc.put("s2info", ObjectUtils.appendIdentityToString(null,
s2).toString());
Template template = Velocity.getTemplate("DemoTemplate.vm");
OutputStreamWriter osw = new OutputStreamWriter(System.out);
template.merge(vc, osw);
osw.flush();
osw.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
--- cut ---
String1: ${s1}, Type is $s1.Class.Name
String2: ${s2}, Type is $s2.Class.Name
String1 Info: ${s1info}
String2 Info: ${s2info}
Equals:
#if ($s1.equals($s2))
True
#else
False
#end
Compare:
#if ($s1 == $s2)
True
#else
False
#end
--- cut ---
produces:
String1: foo, Type is java.lang.String
String2: foo, Type is java.lang.String
String1 Info: [EMAIL PROTECTED]
String2 Info: [EMAIL PROTECTED]
Equals:
True
Compare:
True
So Velocity == is not the same as Java == for Strings. It is the same
as equals().
Best regards
Henning
--
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen INTERMETA GmbH
[EMAIL PROTECTED] +49 9131 50 654 0 http://www.intermeta.de/
RedHat Certified Engineer -- Jakarta Turbine Development -- hero for hire
Linux, Java, perl, Solaris -- Consulting, Training, Development
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