Merge branch '2.11' of github.com:FasterXML/jackson-dataformats-text into 2.11

Author: cowtowncoder

csv/src/main/java/com/fasterxml/jackson/dataformat/csv/CsvParser.java

@@ -132,6 +132,13 @@ public enum Feature
          * @since 2.9
          */
         INSERT_NULLS_FOR_MISSING_COLUMNS(false),
+
+        /**
+         * Feature that enables coercing an empty {@link String} to `null`
+         *
+         * Feature is disabled by default
+         */
+        EMPTY_STRING_AS_NULL(false)
         ;
 
         final boolean _defaultState;
@@ -1106,6 +1113,9 @@ public String getText() throws IOException {
         if (_currToken == JsonToken.FIELD_NAME) {
             return _currentName;
         }
+        if (_currentValue.equals("")) {
+            return isEnabled(CsvParser.Feature.EMPTY_STRING_AS_NULL) ? null : _currentValue;
+        }
         return _currentValue;
     }
 

csv/src/test/java/com/fasterxml/jackson/dataformat/csv/deser/EmptyStringAsNullTest.java

@@ -0,0 +1,65 @@
+package com.fasterxml.jackson.dataformat.csv.deser;
+
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectReader;
+import com.fasterxml.jackson.dataformat.csv.CsvMapper;
+import com.fasterxml.jackson.dataformat.csv.CsvParser;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.*;
+
+/**
+ * Test for {@link CsvParser.Feature#EMPTY_STRING_AS_NULL}
+ */
+public class EmptyStringAsNullTest {
+
+
+    @JsonPropertyOrder({"firstName", "middleName", "lastName"})
+    static class TestUser {
+        public String firstName, middleName, lastName;
+    }
+
+    @Test
+    public void givenFeatureDisabledByDefault_whenColumnIsEmptyString_thenParseAsEmptyString() throws IOException {
+        // setup test data
+        TestUser expectedTestUser = new TestUser();
+        expectedTestUser.firstName = "Grace";
+        expectedTestUser.middleName = "";
+        expectedTestUser.lastName = "Hopper";
+        CsvMapper csvMapper = CsvMapper.builder().build();
+        ObjectReader objectReader = csvMapper.readerFor(TestUser.class).with(csvMapper.schemaFor(TestUser.class));
+        String csv = "Grace,,Hopper";
+
+        // execute
+        TestUser actualTestUser = objectReader.readValue(csv);
+
+        // test
+        assertNotNull(actualTestUser);
+        assertEquals(expectedTestUser.firstName, actualTestUser.firstName);
+        assertEquals(expectedTestUser.middleName, actualTestUser.middleName);
+        assertEquals(expectedTestUser.lastName, actualTestUser.lastName);
+    }
+
+    @Test
+    public void givenFeatureEnabled_whenColumnIsEmptyString_thenParseAsNull() throws IOException {
+        // setup test data
+        TestUser expectedTestUser = new TestUser();
+        expectedTestUser.firstName = "Grace";
+        expectedTestUser.lastName = "Hopper";
+        CsvMapper csvMapper = CsvMapper.builder().enable(CsvParser.Feature.EMPTY_STRING_AS_NULL).build();
+        ObjectReader objectReader = csvMapper.readerFor(TestUser.class).with(csvMapper.schemaFor(TestUser.class));
+        String csv = "Grace,,Hopper";
+
+        // execute
+        TestUser actualTestUser = objectReader.readValue(csv);
+
+        // test
+        assertNotNull(actualTestUser);
+        assertEquals(expectedTestUser.firstName, actualTestUser.firstName);
+        assertNull("The column that contains an empty String should be deserialized as null ", actualTestUser.middleName);
+        assertEquals(expectedTestUser.lastName, actualTestUser.lastName);
+    }
+}

release-notes/CREDITS-2.x

@@ -84,3 +84,9 @@ Vincent Boulaye (vboulaye@github)
 * Implemented #15: Add a `CsvParser.Feature.SKIP_EMPTY_LINES` to allow
   skipping empty rows
  (2.10.1)
+
+Tyler Carpenter-Rivers (tyler2cr@github)
+#7: Add `CsvParser.Feature.EMPTY_STRING_AS_NULL` to allow coercing empty Strings
+  into `null` values
+ (2.11.0)
+

release-notes/VERSION-2.x

@@ -10,7 +10,9 @@ Modules:
 
 2.11.0 (not yet released)
 
--
+#7: Add `CsvParser.Feature.EMPTY_STRING_AS_NULL` to allow coercing empty Strings
+  into `null` values
+ (contributed by Tyler C-R)
 
 2.10.1 (not yet released)