Github user chinmaykolhatkar commented on a diff in the pull request:
https://github.com/apache/incubator-apex-malhar/pull/154#discussion_r48704818
--- Diff:
contrib/src/main/java/com/datatorrent/contrib/parser/CellProcessorBuilder.java
---
@@ -0,0 +1,456 @@
+/**
+ * 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 com.datatorrent.contrib.parser;
+
+import java.util.Map;
+
+import org.supercsv.cellprocessor.Optional;
+import org.supercsv.cellprocessor.ParseBool;
+import org.supercsv.cellprocessor.ParseChar;
+import org.supercsv.cellprocessor.ParseDate;
+import org.supercsv.cellprocessor.ParseDouble;
+import org.supercsv.cellprocessor.ParseInt;
+import org.supercsv.cellprocessor.ParseLong;
+import org.supercsv.cellprocessor.constraint.DMinMax;
+import org.supercsv.cellprocessor.constraint.Equals;
+import org.supercsv.cellprocessor.constraint.LMinMax;
+import org.supercsv.cellprocessor.constraint.StrMinMax;
+import org.supercsv.cellprocessor.constraint.StrRegEx;
+import org.supercsv.cellprocessor.constraint.Strlen;
+import org.supercsv.cellprocessor.ift.CellProcessor;
+import org.supercsv.cellprocessor.ift.DoubleCellProcessor;
+import org.supercsv.cellprocessor.ift.LongCellProcessor;
+import org.supercsv.util.CsvContext;
+
+import org.apache.commons.lang3.StringUtils;
+
+import com.datatorrent.contrib.parser.DelimitedSchema.FIELD_TYPE;
+
+/**
+ * Helper class with methods to generate CellProcessor objects. Cell
processors
+ * are an integral part of reading and writing with Super CSV - they
automate
+ * the data type conversions, and enforce constraints. They implement the
chain
+ * of responsibility design pattern - each processor has a single,
well-defined
+ * purpose and can be chained together with other processors to fully
automate
+ * all of the required conversions and constraint validation for a single
+ * delimited record.
+ *
+ */
+public class CellProcessorBuilder
+{
+
+ /**
+ * Method to get cell processors for given field type and constraints
+ *
+ * @param fieldType
+ * data type of the field
+ * @param constraints
+ * a map of constraints
+ * @return
+ */
+ public static CellProcessor getCellProcessor(FIELD_TYPE fieldType,
Map<String, Object> constraints)
+ {
+ switch (fieldType) {
+ case STRING:
+ return getStringCellProcessor(constraints);
+ case INTEGER:
+ return getIntegerCellProcessor(constraints);
+ case LONG:
+ return getLongCellProcessor(constraints);
+ case FLOAT:
+ case DOUBLE:
+ return getDoubleCellProcessor(constraints);
+ case CHARACTER:
+ return getCharCellProcessor(constraints);
+ case BOOLEAN:
+ return getBooleanCellProcessor(constraints);
+ case DATE:
+ return getDateCellProcessor(constraints);
+ default:
+ return null;
+ }
+ }
+
+ /**
+ * Method to get cellprocessor for String with constraints. These
constraints
+ * are evaluated against the String field for which this cellprocessor is
+ * defined.
+ *
+ * @param constraints
+ * map of constraints applicable to String
+ * @return CellProcessor
+ */
+ private static CellProcessor getStringCellProcessor(Map<String, Object>
constraints)
+ {
+ Boolean required = constraints.get(DelimitedSchema.REQUIRED) == null ?
null : Boolean
+ .parseBoolean((String)constraints.get(DelimitedSchema.REQUIRED));
--- End diff --
Why should this class care about the conversion to from strings to
respective types?
Also if everything is going to be string, why not have a Map<String, String>
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