Struts tag to obtain size of a Collection

[Sam Drake]

Hi,
How am I supposed to check whether the size of an array list in session, (say arrayList) is greater than zero or not using <logic: tag?
eg:<logic:greaterThan name="arrayList property="???" value="0">
// Something
</logic:greaterThan>

What is the property tag going to hold?
Plz help.
regards,
Sam.

[Josh Landin]

Sam,
Since all Collection implementors have size() and isEmpty() methods that yield the info you need, you can start there. If you only want to check if the Collection has elements, you can use:

<logic:notEmpty name="myArrayList">
 ...

OR

<logic:notEqual name="myArrayList" property="empty" value="true">
 ...

Both of these will use the isEmpty() method on the Collection to determine the logic return.
I typically use a transfer object over the Collection class and add helper methods like getSize(), isPlural(), etc. In that case a simple logic tag can check the size more precisely:

<logic:equal name="myArrayList" property="size" value="5">
 ...
<logic:lessThan name="myArrayList" property="size" value="5">
 ...
<logic:greaterThan name="myArrayList" property="size" value="5">
 ...

HTH,
--
Josh