Capture Data Not Joined in a Lookup
Updated: Feb 21, 2022
/* * Copyright (c) 2006-2022 North Concepts Inc. All rights reserved. * Proprietary and Confidential. Use is subject to license terms. * * https://northconcepts.com/data-pipeline/licensing/ */ package com.northconcepts.datapipeline.examples.cookbook; import java.io.File; import java.util.List; import com.northconcepts.datapipeline.core.DataReader; import com.northconcepts.datapipeline.core.FieldList; import com.northconcepts.datapipeline.core.Record; import com.northconcepts.datapipeline.core.RecordList; import com.northconcepts.datapipeline.core.StreamWriter; import com.northconcepts.datapipeline.csv.CSVReader; import com.northconcepts.datapipeline.job.Job; import com.northconcepts.datapipeline.memory.MemoryWriter; import com.northconcepts.datapipeline.transform.TransformingReader; import com.northconcepts.datapipeline.transform.lookup.DataReaderLookup; import com.northconcepts.datapipeline.transform.lookup.Lookup; import com.northconcepts.datapipeline.transform.lookup.LookupTransformer; public class CaptureDataNotJoinedInLookup { public static void main(String[] args) { DataReader reader = new CSVReader(new File("example/data/input/credit-balance.csv")) .setFieldNamesInFirstRow(true); /* * This lookup matches [credit-balance-01.csv].[Rating] to * [rating-table-01.csv].[rating_code] to return * [rating-table-01.csv].[rating_description] */ Lookup lookup = new DataReaderLookup( new CSVReader(new File("example/data/input/rating-table-01.csv")) .setFieldNamesInFirstRow(true), new FieldList("rating_code"), new FieldList("rating_description")); MemoryWriter discardWriter = new MemoryWriter(); reader = new TransformingReader(reader, discardWriter) .add(new DiscardLookupTransformer(new FieldList("Rating"), lookup) .setAllowNoResults(true)); Job.run(reader, new StreamWriter(System.out)); System.out.println("=================================================================================="); System.out.println("Not Joined Records: " + discardWriter.getRecordList()); } private static class DiscardLookupTransformer extends LookupTransformer { public DiscardLookupTransformer(FieldList fields, Lookup lookup) { super(fields, lookup); } @Override protected RecordList noResults(Record originalRecord, List> arguments) { if (isAllowNoResults()) { getReader().getDiscardWriter().write(originalRecord); } return super.noResults(originalRecord, arguments); } } }