private Constraint<T> getConstraint(String name) throws XmlParseException {
		Class<? extends Constraint<T>> constraintClass = constraintClassMap.get(name);
		if (constraintClass == null) {
			return null;
		}
		try {
			return constraintClass.newInstance();
		}
		catch (Exception e) {
			throw new XmlParseException(
				"Can't create constraint instance for class " + constraintClass.getName(), e);
		}
	}
Loads the tree from an xml constraint file. Note: this method can be called multiple times,
with each call appending to the existing tree. 
@param file the file that contains the xml for the constraint.
@throws IOException if an I/O problem occurs reading from the stream.
@throws XmlParseException if the XML is not property formatted or a tag that is not
a constraint name or property name is encountered.
Ghidra/Framework/Generic/src/main/java/generic/constraint/DecisionTree.java