mbeckerle commented on a change in pull request #273: WIP: Add User Defined Functions Capability URL: https://github.com/apache/incubator-daffodil/pull/273#discussion_r337051089
########## File path: daffodil-runtime1/src/main/scala/org/apache/daffodil/dpath/UserDefinedFunctionBase.scala ########## @@ -0,0 +1,35 @@ +/* + * 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. + */ + +package org.apache.daffodil.dpath + +import org.apache.daffodil.exceptions.Assert +import java.lang.reflect.Method +import org.apache.daffodil.udf.UserDefinedFunction + +/** + * Both the evaluate method and the User Defined Function instance are passed in, as both are needed by the Method.invoke + * function. + */ +case class UserDefinedFunctionCall(recipes: List[CompiledDPath], userDefinedFunction: UserDefinedFunction, evaluateFxn: Method) + extends FNArgsList(recipes) { + override def computeValue(values: List[Any], dstate: DState) = { + val jValues = values.map { _.asInstanceOf[Object] } + val res = evaluateFxn.invoke(userDefinedFunction, jValues: _*) Review comment: So let me summarize: 1) user checks for an error (e.g., arg out of range) - author of UDF chooses that this should be an error that causes backtracking when parsing - we want a Processing Error. Author of UDF must be able to select this behavior, and distinguish from a fatal error, so we need UDFProcessingError(cause/message) class to throw. I think this is a new class derived from ProcessingError that we need. 2) errors at setup time - SDE or added SDW that accompanies an SDE. These are all detected by daffodil, so nothing for users to do here. 3) unexpected error - user's code in the UDF just fails somehow - catch cause, and throw new UDFFatalException, which is an abort and captures the backtrace. This should throw to top level and gives us the option to say not "this is a bug in daffodil...." but to detect this class and issue a slightly different message. This last one is questionable. One can argue we should just not catch such exceptions, and they should fly out to top level and stop things. I think if the user does nothing to catch these, perhaps we should be doing nothing to catch these. I think UDF authors do need a positive way to cause a fatal exception that is assured NOT to be caught and cause a processing error. `class UDFFatalException(cause: Throwable) extends Abort(cause) ` ---------------------------------------------------------------- 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
