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javastringtemplate-4

StringTemplate list of attributes defined for a given template

I am getting started with StringTemplate 4 and I am trying to create a template from a simple string stored in a database. I use something like this:

STGroup group = new STGroupString(null, someTemplateString, '$', '$');
ST st = group.getInstanceOf(someTemplateName);
st.add(someAttribute, someValue);

Now everything works fine if I define all or less than the attribute defined for the template someTemplateName. Now if I try to add an attribute that doesn't exist, I get the following exception:

no such attribute: fake
java.lang.IllegalArgumentException: no such attribute: fake
  ...

which makes sense. However, it seems like there's no way for me to know beforehand which attributes are defined for the template someTemplateName. I was expecting to find something like:

bool isDef = st.isDefined(someAttribute);

but there's no such method. Am I correct? Is there any way around this?

Solution

  • You can use st.impl.formalArguments to access the Map<String, FormalArgument> where the arguments are defined. Note that for some templates this field will be null.