8294008: Grapheme implementation of setText() throws IndexOutOfBounds…

…Exception

Reviewed-by: joehw, smarks

src/java.base/share/classes/sun/util/locale/provider/BreakIteratorProviderImpl.java

@@ -317,7 +317,15 @@ public boolean equals(Object o) {
         }
     }
 
-    // Implementation only for calling Grapheme.nextBoundary()
+    /**
+     * Implementation only for calling Grapheme.nextBoundary().
+     *
+     * This is a special-purpose CharSequence that represents characters in the
+     * index range [0..endIndex) of the underlying CharacterIterator, even if
+     * that CharacterIterator represents the subrange of some string. The calling
+     * code in GraphemeBreakIterator takes care to ensure that only valid indexes
+     * into the src are used.
+     */
     static final class CharacterIteratorCharSequence implements CharSequence {
         CharacterIterator src;
         CharacterIteratorCharSequence(CharacterIterator ci) {
@@ -326,7 +334,10 @@ static final class CharacterIteratorCharSequence implements CharSequence {
 
         @Override
         public int length() {
-            return src.getEndIndex() - src.getBeginIndex();
+            // Return the entire CharSequence length (0 to endIndex), not to
+            // be confused with the text range length (beginIndex to endIndex)
+            // of the underlying CharacterIterator.
+            return src.getEndIndex();
         }
 
         @Override

test/jdk/java/text/BreakIterator/BreakIteratorTest.java

@@ -26,6 +26,7 @@
  * @bug 4035266 4052418 4068133 4068137 4068139 4086052 4095322 4097779
  *      4097920 4098467 4111338 4113835 4117554 4143071 4146175 4152117
  *      4152416 4153072 4158381 4214367 4217703 4638433 8264765 8291660
+ *      8294008
  * @library /java/text/testlib
  * @run main/timeout=2000 BreakIteratorTest
  * @summary test BreakIterator
@@ -1468,4 +1469,8 @@ public void TestGraphemeBreak() throws Exception {
                     generalIteratorTest(characterBreak, expected);
                 });
     }
+
+    public void TestSetTextIOOBException() {
+        BreakIterator.getCharacterInstance().setText(new StringCharacterIterator("abcfefg", 1, 5, 3));
+    }
 }