stevedlawrence commented on a change in pull request #273: WIP: Add User Defined Functions Capability URL: https://github.com/apache/incubator-daffodil/pull/273#discussion_r334941433
########## File path: daffodil-udf/README.md ########## @@ -0,0 +1,61 @@ +<!-- + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--> + +# User Defined Functions + +## Introduction + +Apache Daffodil (incubating) allows execution of Java external/user defined functions in DPath Expressions. + +## Getting Started + +The implementer will be expected to provide a JAR via the classpath containing at least 2 classes: a provider class and its associated serializable function class(es). + +The JAR can have as many provider classes as desired as long as the classes are registered in the *services* folder. + +### UDF Implementation + +#### Provider Classes + +The provider class will be an implementation of Daffodil's `UDFuntionProvider` class. This class must initialize its functionClasses array with all the classes it's providing. It must also implement a lookup function that returns an initialized function class object based on a supplied name and namespace. Review comment: I think this is out of date now. UDFunctionProvider was changed to UserDefinedFunctionProvider, and the functionClasses array no longer exists. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
