Package org.stringtemplate.v4.misc

Class Aggregate

  • public class Aggregate
extends Object
    An automatically created aggregate of properties.

    I often have lists of things that need to be formatted, but the list items are actually pieces of data that are not already in an object. I need ST to do something like:

    Ter=3432
    Tom=32234
    ....

    using template:

    $items:{it.name$=$it.type$}$

    This example will call getName() on the objects in items attribute, but what if they aren't objects? I have perhaps two parallel arrays instead of a single array of objects containing two fields. One solution is allow Maps to be handled like properties so that it.name would fail getName() but then see that it's a Map and do it.get("name") instead.

    This very clean approach is espoused by some, but the problem is that it's a hole in my separation rules. People can put the logic in the view because you could say: "go get bob's data" in the view:

    Bob's Phone: $db.bob.phone$

    A view should not be part of the program and hence should never be able to go ask for a specific person's data.

    After much thought, I finally decided on a simple solution. I've added setAttribute variants that pass in multiple property values, with the property names specified as part of the name using a special attribute name syntax: "name.{propName1,propName2,...}". This object is a special kind of HashMap that hopefully prevents people from passing a subclass or other variant that they have created as it would be a loophole. Anyway, the AggregateModelAdaptor.getProperty(org.stringtemplate.v4.Interpreter, org.stringtemplate.v4.ST, org.stringtemplate.v4.misc.Aggregate, java.lang.Object, java.lang.String) method looks for Aggregate as a special case and does a get(java.lang.String) instead of getPropertyName.

    • Constructor Detail

      • Aggregate

        public Aggregate()

    • Method Detail

      • put

        protected void put​(String propName,
                   Object propValue)
        Allow StringTemplate to add values, but prevent the end user from doing so.