[LANG-407] StringUtils.length(String) returns null-safe length.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@618882 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/lang/StringUtils.java

@@ -4581,6 +4581,18 @@ public class StringUtils {
         }
     }
 
+    /**
+     * Gets a String's length or <code>0</code> if the String is <code>null</code>.
+     * 
+     * @param str
+     *            a String or <code>null</code>
+     * @return String length or <code>0</code> if the String is <code>null</code>.
+     * @since 2.4
+     */
+    public static int length(String str) {
+        return str == null ? 0 : str.length();
+    }
+    
     // Centering
     //-----------------------------------------------------------------------
     /**

src/test/org/apache/commons/lang/StringUtilsTest.java

@@ -1403,6 +1403,15 @@ public class StringUtilsTest extends TestCase {
         assertEquals("  abc", StringUtils.leftPad("abc", 5, ""));
     }
 
+    public void testLength() {
+        assertEquals(0, StringUtils.length(null));
+        assertEquals(0, StringUtils.length(""));
+        assertEquals(0, StringUtils.length(StringUtils.EMPTY));
+        assertEquals(1, StringUtils.length("A"));
+        assertEquals(1, StringUtils.length(" "));
+        assertEquals(8, StringUtils.length("ABCDEFGH"));
+    }
+    
     //-----------------------------------------------------------------------
     public void testCenter_StringInt() {
         assertEquals(null, StringUtils.center(null, -1));
@@ -1647,6 +1656,7 @@ public class StringUtilsTest extends TestCase {
     public void testEMPTY() {
         assertNotNull(StringUtils.EMPTY);
         assertEquals("", StringUtils.EMPTY);
+        assertEquals(0, StringUtils.EMPTY.length());
     }
     
     public void testRemoveStart() {