Adding StringUtil.isBlank(String) and StringUtil.isNotBlank(String) with

tests

jetty-util/src/main/java/org/eclipse/jetty/util/StringUtil.java

@@ -370,6 +370,85 @@ public class StringUtil
         }
     }
 
+    /* ------------------------------------------------------------ */
+    /**
+     * Test if a string is null or only has whitespace characters in it.
+     * <p>
+     * Note: uses codepoint version of {@link Character#isWhitespace(int)} to support Unicode better.
+     * 
+     * <pre>
+     *   isBlank(null)   == true
+     *   isBlank("")     == true
+     *   isBlank("\r\n") == true
+     *   isBlank("\t")   == true
+     *   isBlank("   ")  == true
+     *   isBlank("a")    == false
+     *   isBlank(".")    == false
+     *   isBlank(";\n")  == false
+     * </pre>
+     * 
+     * @param str
+     *            the string to test.
+     * @return true if string is null or only whitespace characters, false if non-whitespace characters encountered.
+     */
+    public static boolean isBlank(String str)
+    {
+        if (str == null)
+        {
+            return true;
+        }
+        int len = str.length();
+        for (int i = 0; i < len; i++)
+        {
+            if (!Character.isWhitespace(str.codePointAt(i)))
+            {
+                // found a non-whitespace, we can stop searching  now
+                return false;
+            }
+        }
+        // only whitespace
+        return true;
+    }
+    
+    /* ------------------------------------------------------------ */
+    /**
+     * Test if a string is not null and contains at least 1 non-whitespace characters in it.
+     * <p>
+     * Note: uses codepoint version of {@link Character#isWhitespace(int)} to support Unicode better.
+     * 
+     * <pre>
+     *   isNotBlank(null)   == false
+     *   isNotBlank("")     == false
+     *   isNotBlank("\r\n") == false
+     *   isNotBlank("\t")   == false
+     *   isNotBlank("   ")  == false
+     *   isNotBlank("a")    == true
+     *   isNotBlank(".")    == true
+     *   isNotBlank(";\n")  == true
+     * </pre>
+     * 
+     * @param str
+     *            the string to test.
+     * @return true if string is not null and has at least 1 non-whitespace character, false if null or all-whitespace characters.
+     */
+    public static boolean isNotBlank(String str)
+    {
+        if (str == null)
+        {
+            return false;
+        }
+        int len = str.length();
+        for (int i = 0; i < len; i++)
+        {
+            if (!Character.isWhitespace(str.codePointAt(i)))
+            {
+                // found a non-whitespace, we can stop searching  now
+                return true;
+            }
+        }
+        // only whitespace
+        return false;
+    }
 
     /* ------------------------------------------------------------ */
     public static boolean isUTF8(String charset)

jetty-util/src/test/java/org/eclipse/jetty/util/StringUtilTest.java

@@ -197,4 +197,34 @@ public class StringUtilTest
         }
         System.err.println(calc);
     }
+    
+    @Test
+    public void testIsBlank() {
+        Assert.assertTrue(StringUtil.isBlank(null));
+        Assert.assertTrue(StringUtil.isBlank(""));
+        Assert.assertTrue(StringUtil.isBlank("\r\n"));
+        Assert.assertTrue(StringUtil.isBlank("\t"));
+        Assert.assertTrue(StringUtil.isBlank("   "));
+                   
+        Assert.assertFalse(StringUtil.isBlank("a"));
+        Assert.assertFalse(StringUtil.isBlank("  a"));
+        Assert.assertFalse(StringUtil.isBlank("a  "));
+        Assert.assertFalse(StringUtil.isBlank("."));
+        Assert.assertFalse(StringUtil.isBlank(";\n"));
+    }
+
+    @Test
+    public void testIsNotBlank() {
+        Assert.assertFalse(StringUtil.isNotBlank(null));
+        Assert.assertFalse(StringUtil.isNotBlank(""));
+        Assert.assertFalse(StringUtil.isNotBlank("\r\n"));
+        Assert.assertFalse(StringUtil.isNotBlank("\t"));
+        Assert.assertFalse(StringUtil.isNotBlank("   "));
+                   
+        Assert.assertTrue(StringUtil.isNotBlank("a"));
+        Assert.assertTrue(StringUtil.isNotBlank("  a"));
+        Assert.assertTrue(StringUtil.isNotBlank("a  "));
+        Assert.assertTrue(StringUtil.isNotBlank("."));
+        Assert.assertTrue(StringUtil.isNotBlank(";\n"));
+    }
 }