Github user mattyb149 commented on a diff in the pull request: https://github.com/apache/nifi/pull/3188#discussion_r237218520 --- Diff: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/lookup/ReaderLookup.java --- @@ -0,0 +1,158 @@ +/* + * 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.nifi.lookup; + +import org.apache.commons.lang3.StringUtils; +import org.apache.nifi.annotation.behavior.DynamicProperty; +import org.apache.nifi.annotation.documentation.CapabilityDescription; +import org.apache.nifi.annotation.documentation.SeeAlso; +import org.apache.nifi.annotation.documentation.Tags; +import org.apache.nifi.annotation.lifecycle.OnDisabled; +import org.apache.nifi.annotation.lifecycle.OnEnabled; +import org.apache.nifi.components.PropertyDescriptor; +import org.apache.nifi.components.ValidationContext; +import org.apache.nifi.components.ValidationResult; +import org.apache.nifi.controller.AbstractControllerService; +import org.apache.nifi.controller.ConfigurationContext; +import org.apache.nifi.expression.ExpressionLanguageScope; +import org.apache.nifi.flowfile.FlowFile; +import org.apache.nifi.logging.ComponentLog; +import org.apache.nifi.processor.exception.ProcessException; +import org.apache.nifi.processor.util.StandardValidators; +import org.apache.nifi.schema.access.SchemaNotFoundException; +import org.apache.nifi.serialization.MalformedRecordException; +import org.apache.nifi.serialization.RecordReader; +import org.apache.nifi.serialization.RecordReaderFactory; + +import java.io.IOException; +import java.io.InputStream; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +@Tags({"lookup", "parse", "record", "row", "reader"}) +@SeeAlso({RecordSetWriterLookup.class}) +@CapabilityDescription("Provides a RecordReaderFactory that can be used to dynamically select another RecordReaderFactory. This service " + + "requires an attribute named 'recordreader.name' to be passed in when asking for a record record, and will throw an exception " + + "if the attribute is missing. The value of 'recordreader.name' will be used to select the RecordReaderFactory that has been " + + "registered with that name. This will allow multiple RecordReaderFactory's to be defined and registered, and then selected " + + "dynamically at runtime by tagging flow files with the appropriate 'recordreader.name' attribute.") +@DynamicProperty(name = "The ", value = "RecordWriterFactory property value", expressionLanguageScope = ExpressionLanguageScope.NONE, + description = "") +public class ReaderLookup extends AbstractControllerService implements RecordReaderFactory { --- End diff -- Now that controller services can have access to attributes, it would be nice to add support in the documentation for `ReadsAttributes` annotations. You don't need to do that here, just leaving it as a reminder for a future improvement Jira :)
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