Referencing a global variable in forloop from Apache Velocity - velocity

Question

I am having trouble with having a formatter within a forloop in Apache Velocity.
#set( $array = ["10000", "3000", "13.456", "1111.13"] )
<ul>
#foreach( $a in $array)
<li>$formatter.print($a)</li>
#end
</ul>
This would be evaluated and print the original expression as a string 4 times
$formatter.print($a)
$formatter.print($a)
$formatter.print($a)
$formatter.print($a)
instead of
10,000.00
3,000.00
13.456
1,111.13
However it seems to work fine with the formatter outside of the scope from the forloop
<p>$formatter.print(123456)</p>
This would work as usual
Can anyone helps me figuring out how to reference a property (in this case $formatter) within a for loop ?

Answer 1

This can happen when one of the following condition is true:
1) The model passed to the velocity does not have the variable "formatter"
2) The method print is returning null or it does not exist
3) The method print accepts a parameter of the wrong type. Try to pass Object...
The following code works for me (notice that I am using an array of double and not any more an array of string):
package test;
import java.io.StringWriter;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
public class VelocityHelloWorld
{
public static void main( String[] args )
throws Exception
{
VelocityEngine ve = new VelocityEngine();
ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
ve.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());
ve.init();
VelocityContext context = new VelocityContext();
context.put("formatter", new Formatter());
Template t = ve.getTemplate( "helloworld.vm" );
StringWriter writer = new StringWriter();
t.merge( context, writer );
System.out.println(writer.toString());
}
}
Velocity:
#set( $array = [10.00 , 20.00, 13.456, 1111.13] )
<ul>
#foreach( $a in $array)
<li>$formatter.print($a)</li>
#end
</ul>
Formatter:
package test;
public class Formatter {
public String print (Object d) {
String s = d.getClass().getName() + ": " + d.toString();
return s;
}
}
The template shows the same behaviour like yours if I substitute in
print (Double d)
Double with Float.
Long story short... I think that you probably need to check the parameter passed to your method.
Of course I think you should use Double and create the array as a list of double and not as a list of strings.

Answer 2

Try ${myref.doIt($var)} syntax to reference context variable. This ensures Velocity does not parse context names incorrectly within strings.