Add a new utility method for trimming strings

Author: joegallo

server/src/main/java/org/elasticsearch/common/Strings.java

@@ -172,6 +172,24 @@ public static String trimLeadingCharacter(String str, char leadingCharacter) {
         return str.substring(i);
     }
 
+    /**
+     * Trim all occurrences of the supplied trailing character from the given String.
+     *
+     * @param str              the String to check
+     * @param trailingCharacter the trailing character to be trimmed
+     * @return the trimmed String
+     */
+    public static String trimTrailingCharacter(String str, char trailingCharacter) {
+        if (hasLength(str) == false) {
+            return str;
+        }
+        int i = str.length();
+        while (i > 0 && str.charAt(i - 1) == trailingCharacter) {
+            i--;
+        }
+        return str.substring(0, i);
+    }
+
     /**
      * Test whether the given string matches the given substring
      * at the given index.

server/src/test/java/org/elasticsearch/common/StringsTests.java

@@ -35,6 +35,7 @@
 import static org.elasticsearch.common.Strings.toLowercaseAscii;
 import static org.elasticsearch.common.Strings.tokenizeByCommaToSet;
 import static org.elasticsearch.common.Strings.trimLeadingCharacter;
+import static org.elasticsearch.common.Strings.trimTrailingCharacter;
 import static org.hamcrest.Matchers.arrayContaining;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.emptyArray;
@@ -121,6 +122,14 @@ public void testTrimLeadingCharacter() {
         assertThat(trimLeadingCharacter("aaa", 'a'), equalTo(""));
     }
 
+    public void testTrimTrailingCharacter() {
+        assertThat(trimTrailingCharacter(null, 'g'), equalTo(null));
+        assertThat(trimTrailingCharacter("", 'g'), equalTo(""));
+        assertThat(trimTrailingCharacter("abcdef", 'g'), equalTo("abcdef"));
+        assertThat(trimTrailingCharacter("abcdefggg", 'g'), equalTo("abcdef"));
+        assertThat(trimTrailingCharacter("aaa", 'a'), equalTo(""));
+    }
+
     public void testToStringToXContent() {
         final ToXContent toXContent;
         final boolean error;