[commons-csv] branch master updated: feat: document duplicate header behavior

[gg...@apache.org]

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ggregory pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-csv.git


The following commit(s) were added to refs/heads/master by this push:
     new 7f335011 feat: document duplicate header behavior
     new bc61b750 Merge pull request #309 from SethFalco/header-docs
7f335011 is described below

commit 7f335011ba5392ddd09a878320010017c26a47ca
Author: Seth Falco <se...@falco.fun>
AuthorDate: Wed Feb 22 23:42:40 2023 +0000

    feat: document duplicate header behavior
---
 .../java/org/apache/commons/csv/CSVRecord.java     |  6 ++--
 .../java/org/apache/commons/csv/CSVRecordTest.java | 32 ++++++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/apache/commons/csv/CSVRecord.java b/src/main/java/org/apache/commons/csv/CSVRecord.java
index 5524d9e8..0e70ad75 100644
--- a/src/main/java/org/apache/commons/csv/CSVRecord.java
+++ b/src/main/java/org/apache/commons/csv/CSVRecord.java
@@ -88,7 +88,7 @@ public final class CSVRecord implements Serializable, Iterable<String> {
     }
 
     /**
-     * Returns a value by name.
+     * Returns a value by name. If multiple instances of the header name exists, only the last occurence is returned.
      *
      * <p>
      * Note: This requires a field mapping obtained from the original parser.
@@ -311,7 +311,9 @@ public final class CSVRecord implements Serializable, Iterable<String> {
     }
 
     /**
-     * Copies this record into a new Map of header name to record value.
+     * Copies this record into a new Map of header name to record value. If multiple instances of a header name exists,
+     * only the last occurence is mapped.
+     *
      * <p>
      * Editing the map does not update this instance.
      * </p>
diff --git a/src/test/java/org/apache/commons/csv/CSVRecordTest.java b/src/test/java/org/apache/commons/csv/CSVRecordTest.java
index 4833c26c..db1ef40c 100644
--- a/src/test/java/org/apache/commons/csv/CSVRecordTest.java
+++ b/src/test/java/org/apache/commons/csv/CSVRecordTest.java
@@ -23,6 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertAll;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
@@ -341,6 +342,37 @@ public class CSVRecordTest {
         assertTrue(recordWithHeader.toString().contains("values="));
     }
 
+    @Test
+    public void testDuplicateHeaderGet() throws IOException {
+        final String csv = "A,A,B,B\n1,2,5,6\n";
+        final CSVFormat format = CSVFormat.DEFAULT.builder().setHeader().build();
+
+        try (final CSVParser parser = CSVParser.parse(csv, format)) {
+            final CSVRecord record = parser.nextRecord();
+
+            assertAll("Test that it gets the last instance of a column when there are duplicate headings",
+                () -> assertEquals("2", record.get("A")),
+                () -> assertEquals("6", record.get("B"))
+            );
+        }
+    }
+
+    @Test
+    public void testDuplicateHeaderToMap() throws IOException {
+        final String csv = "A,A,B,B\n1,2,5,6\n";
+        final CSVFormat format = CSVFormat.DEFAULT.builder().setHeader().build();
+
+        try (final CSVParser parser = CSVParser.parse(csv, format)) {
+            final CSVRecord record = parser.nextRecord();
+            final Map<String, String> map = record.toMap();
+
+            assertAll("Test that it gets the last instance of a column when there are duplicate headings",
+                () -> assertEquals("2", map.get("A")),
+                () -> assertEquals("6", map.get("B"))
+            );
+        }
+    }
+
     private void validateMap(final Map<String, String> map, final boolean allowsNulls) {
         assertTrue(map.containsKey(EnumHeader.FIRST.name()));
         assertTrue(map.containsKey(EnumHeader.SECOND.name()));