Re: The new map syntax

-----Original Message-----
From: "Nikhil G. Daddikar" <[email protected]>
To: [email protected]
Date: Fri, 18 Nov 2005 10:52:24 +0530
Subject: [WebMacro-user] The new map syntax

> I like the new #set $map = { k1: v1, k2:v2 } syntax. The only problem
> is 
> that it does not use the "List Ordered" Map i.e. when I  want to say 
> render a select list  from it, it shows things not in the order in
> which 
> the map was defined. Is there a way where I can specify the 
> implementation class to use? I use JDK 1.5 and  would like to specify 
> the LinkedHashMap.

No, I don't believe this is possible. 

I'd say it's generally better not rely on the order of definition of map
elements.

If you need ordering you can simply create 2 lists. It's not that pretty
but...

Alternatively, and usually this makes sense for "human" use, you would
populate lists etc based on a sort order rather than listed order - so you
can just write a trivial helper to return a sorted list of the keys:

public class SortTool
{
    public static final Object sort(Object list)
    {
        List l = ListUtil.toList(list);
        Collections.sort(l);
        return l;        
    }
}

...and use it like this:

#set $sortedKeys = $Sorter.sort($myMap.keySet().iterator())

...of course you can make the usage of this tool a LOT nicer by adding
some more intelligence / overidden methods:

public class SortTool
{
    public static final Object sort(Object list)
    {
        List l = ListUtil.toList(list);
        Collections.sort(l);
        return l;        
    }
    
    public static final Object sortKeys(Map map)
    {
        return sort( map.keySet().iterator());        
    }
}

...and use it like this:

#set $sortedKeys = $Sorter.sortKeys($myMap)


Cheers



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