From ad433ecc1684683e3eba11dc198cc0d853299410 Mon Sep 17 00:00:00 2001
From: Gary Gregory <garydgregory@gmail.com>
Date: Wed, 1 Jul 2020 17:21:55 -0400
Subject: [PATCH] Make internal API null-safe and Javadoc.

---
 .../commons/lang3/CharSequenceUtils.java      | 23 +++++++++++--------
 .../commons/lang3/CharSequenceUtilsTest.java  |  1 +
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java b/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
index fc5350f52..ad12d9938 100644
--- a/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
+++ b/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
@@ -299,20 +299,23 @@ public class CharSequenceUtils {
     }
 
     /**
-     * Green implementation of toCharArray.
+     * Converts the given CharSequence to a char[].
      *
-     * @param cs the {@code CharSequence} to be processed
-     * @return the resulting char array
+     * @param source the {@code CharSequence} to be processed.
+     * @return the resulting char array, never null.
      * @since 3.11
      */
-    public static char[] toCharArray(final CharSequence cs) {
-        if (cs instanceof String) {
-            return ((String) cs).toCharArray();
+    public static char[] toCharArray(final CharSequence source) {
+        final int len = StringUtils.length(source);
+        if (len == 0) {
+            return ArrayUtils.EMPTY_CHAR_ARRAY;
         }
-        final int sz = cs.length();
-        final char[] array = new char[cs.length()];
-        for (int i = 0; i < sz; i++) {
-            array[i] = cs.charAt(i);
+        if (source instanceof String) {
+            return ((String) source).toCharArray();
+        }
+        final char[] array = new char[len];
+        for (int i = 0; i < len; i++) {
+            array[i] = source.charAt(i);
         }
         return array;
     }
diff --git a/src/test/java/org/apache/commons/lang3/CharSequenceUtilsTest.java b/src/test/java/org/apache/commons/lang3/CharSequenceUtilsTest.java
index b21144c1c..7e2f4d164 100644
--- a/src/test/java/org/apache/commons/lang3/CharSequenceUtilsTest.java
+++ b/src/test/java/org/apache/commons/lang3/CharSequenceUtilsTest.java
@@ -186,6 +186,7 @@ public class CharSequenceUtilsTest {
         final char[] expected = builder.toString().toCharArray();
         assertArrayEquals(expected, CharSequenceUtils.toCharArray(builder));
         assertArrayEquals(expected, CharSequenceUtils.toCharArray(builder.toString()));
+        assertArrayEquals(ArrayUtils.EMPTY_CHAR_ARRAY, CharSequenceUtils.toCharArray(null));
     }
 
     static class WrapperString implements CharSequence {