From 8b23cbb6a813f6e99843c766f7f0718122d6dd85 Mon Sep 17 00:00:00 2001
From: Sigee <sigee15@gmail.com>
Date: Thu, 19 Sep 2024 15:46:49 +0200
Subject: [PATCH] Extract method to reduce cognitive complexity of
 createHeaders()

---
 .../org/apache/commons/csv/CSVParser.java     | 72 +++++++++++--------
 1 file changed, 42 insertions(+), 30 deletions(-)

diff --git a/src/main/java/org/apache/commons/csv/CSVParser.java b/src/main/java/org/apache/commons/csv/CSVParser.java
index 471a43c12..98b797ca6 100644
--- a/src/main/java/org/apache/commons/csv/CSVParser.java
+++ b/src/main/java/org/apache/commons/csv/CSVParser.java
@@ -504,42 +504,54 @@ private Headers createHeaders() throws IOException {
                 headerRecord = formatHeader;
             }
 
-            // build the name to index mappings
-            if (headerRecord != null) {
-                // Track an occurrence of a null, empty or blank header.
-                boolean observedMissing = false;
-                for (int i = 0; i < headerRecord.length; i++) {
-                    final String header = headerRecord[i];
-                    final boolean blankHeader = CSVFormat.isBlank(header);
-                    if (blankHeader && !format.getAllowMissingColumnNames()) {
-                        throw new IllegalArgumentException(
-                            "A header name is missing in " + Arrays.toString(headerRecord));
-                    }
+            headerNames = getHeaderNames(headerRecord, hdrMap);
+        }
+        // Make header names Collection immutable
+        return new Headers(hdrMap, headerNames == null ? Collections.emptyList() : Collections.unmodifiableList(headerNames));
+    }
 
-                    final boolean containsHeader = blankHeader ? observedMissing : hdrMap.containsKey(header);
-                    final DuplicateHeaderMode headerMode = format.getDuplicateHeaderMode();
-                    final boolean duplicatesAllowed = headerMode == DuplicateHeaderMode.ALLOW_ALL;
-                    final boolean emptyDuplicatesAllowed = headerMode == DuplicateHeaderMode.ALLOW_EMPTY;
+    /**
+     *  Build the name to index mappings
+     *
+     * @param headerRecord the record as an array of values, or {@code null} if the end of the stream has been reached
+     * @param headerMap the header column positions (0-based)
+     * @return header names in column order, or {@code null} if {@code headerRecord} is {@code null}.
+     */
+    private List<String> getHeaderNames(final String[] headerRecord, final Map<String, Integer> headerMap) {
+        List<String> headerNames = null;
+        if (headerRecord != null) {
+            // Track an occurrence of a null, empty or blank header.
+            boolean observedMissing = false;
+            for (int i = 0; i < headerRecord.length; i++) {
+                final String header = headerRecord[i];
+                final boolean blankHeader = CSVFormat.isBlank(header);
+                if (blankHeader && !format.getAllowMissingColumnNames()) {
+                    throw new IllegalArgumentException(
+                        "A header name is missing in " + Arrays.toString(headerRecord));
+                }
 
-                    if (containsHeader && !duplicatesAllowed && !(blankHeader && emptyDuplicatesAllowed)) {
-                        throw new IllegalArgumentException(
-                            String.format(
-                                "The header contains a duplicate name: \"%s\" in %s. If this is valid then use CSVFormat.Builder.setDuplicateHeaderMode().",
-                                header, Arrays.toString(headerRecord)));
-                    }
-                    observedMissing |= blankHeader;
-                    if (header != null) {
-                        hdrMap.put(header, Integer.valueOf(i)); // N.B. Explicit (un)boxing is intentional
-                        if (headerNames == null) {
-                            headerNames = new ArrayList<>(headerRecord.length);
-                        }
-                        headerNames.add(header);
+                final boolean containsHeader = blankHeader ? observedMissing : headerMap.containsKey(header);
+                final DuplicateHeaderMode headerMode = format.getDuplicateHeaderMode();
+                final boolean duplicatesAllowed = headerMode == DuplicateHeaderMode.ALLOW_ALL;
+                final boolean emptyDuplicatesAllowed = headerMode == DuplicateHeaderMode.ALLOW_EMPTY;
+
+                if (containsHeader && !duplicatesAllowed && !(blankHeader && emptyDuplicatesAllowed)) {
+                    throw new IllegalArgumentException(
+                        String.format(
+                            "The header contains a duplicate name: \"%s\" in %s. If this is valid then use CSVFormat.Builder.setDuplicateHeaderMode().",
+                            header, Arrays.toString(headerRecord)));
+                }
+                observedMissing |= blankHeader;
+                if (header != null) {
+                    headerMap.put(header, Integer.valueOf(i)); // N.B. Explicit (un)boxing is intentional
+                    if (headerNames == null) {
+                        headerNames = new ArrayList<>(headerRecord.length);
                     }
+                    headerNames.add(header);
                 }
             }
         }
-        // Make header names Collection immutable
-        return new Headers(hdrMap, headerNames == null ? Collections.emptyList() : Collections.unmodifiableList(headerNames));
+        return headerNames;
     }
 
     /**