Sort map with velocity - sorting

Question

I populated a map from a xml document in velocity successfully.
Now I am trying to soft the map.
Any one have an idea how to do this.
Here is my velocity template
#set ($root = $context.root)
#set ($nodes = $root.selectNodes("MedicalHIstoryResponse/MedicalResponses"))
#set ($container = {})
#foreach( $node in $nodes )
#set($recordId = $!node.selectSingleNode("recordId/text()").getStringValue())
#set($myHashMap = {
"eventDate": $!node.selectSingleNode("EventDate/text()").getStringValue(),
"eventType": $!node.selectSingleNode("EventType/text()").getStringValue(),
"description": $!node.selectSingleNode("Description/text()").getStringValue(),
"recordId": $recordId,
"parentRecordId": $!node.selectSingleNode("parentRecordId/text()").getStringValue(),
"noofAttachment": $!node.selectSingleNode("noofAttachment/text()").getStringValue(),
"noofLinkFolder": $!node.selectSingleNode("noofLinkFolder/text()").getStringValue(),
"hide": $!node.selectSingleNode("hide/text()").getStringValue(),
"addedBy": $!node.selectSingleNode("addedBy/text()").getStringValue()
})
#set ($discard = $container.put($recordId, $myHashMap))
#end
#foreach($obj in $container)
$obj
#end

Answer 1

You can use a TreeMap instead of an HashMap. It will keep entries sorted by key.
You will need a small tool to create empty maps in VTL (or you can use the definitely ugly hack:
#set($dummy="")
#set($container = $dummy.class.forName("java.util.TreeMap").newInstance())
at least for testing purposes).

Answer 2

Quick solution: use Velocity Sort Tool - docs here.
#foreach($obj in $sorter.sort($container))
$obj
#end
You'll need to add the sort tool to the Velocity context using
VelocityContext velocityContext = new VelocityContext(variableMap);
// now add in the velocity tools required
velocityContext.put("sorter", new SortTool());
Better solution: follow MVC principles and do all this work in Java code. Amongst other benefits, this would give you the flexibility to apply a custom sort order (Comparator). See my other SO answer here for a full explanation and justification.