Added underscored method with tests and documentation

README.md

@@ -631,6 +631,16 @@ isBlank("test")
 // result => false)
 ```
 
+## underscored
+
+underscored returns a string that represents the passed in string in all lowercase and underscores
+between words.
+
+```java
+underscored("MozTransform")
+// result => "moz_transform")
+```
+
 ## Inspiration
 
 This library is inspired by [dleitee/strman](https://github.com/dleitee/strman).

src/main/java/strman/Strman.java

@@ -1310,12 +1310,38 @@ public abstract class Strman {
      * Checks if string is empty.  This is a null safe check and will return true when string is null.
      *
      * @param input The input string
-     * @return true if string is null or empty
+     * @return true if input string is null or empty
      */
 	public static boolean isBlank(String input) {
 		return input == null || input.isEmpty();
 	}
 
+    /**
+     * Changes passed in string to all lower case and adds underscore between words.
+     *
+     * @param input The input string
+     * @return the input string in all lower case with underscores between words
+     */
+	public static String underscored(String input) {
+		String result = null;
+		if (input != null) {
+			StringBuffer resultBuffer = new StringBuffer();
+			char[] inputArray = input.toCharArray();
+			for(int i = 0; i < inputArray.length; i++) {
+				char nextChar = inputArray[i];
+				if (Character.isUpperCase(nextChar)) {
+					//start new word
+					if (resultBuffer.length() != 0) {
+						resultBuffer.append("_");
+					}
+				}
+				resultBuffer.append(nextChar);
+			}
+			result = resultBuffer.toString().toLowerCase();
+		}
+		return result;
+	}
+	
     private static void validate(String value, Predicate<String> predicate, final Supplier<String> supplier) {
         if (predicate.test(value)) {
             throw new IllegalArgumentException(supplier.get());

src/test/java/strman/StrmanTest.java

@@ -1040,4 +1040,20 @@ public class StrmanTest {
     public void isBlank_shouldReturnFalseIfNotEmpty() {
     	assertFalse(isBlank("ac"));
     }
+    
+    @Test
+    public void underscored_shouldReturnUnderscoredString() {
+    	assertThat(underscored("MozTransform"), equalTo("moz_transform"));
+    }
+    
+    @Test
+    public void underscored_shouldReturnEmptyStringIfEmptyStringPassedIn() {
+    	assertThat(underscored(""), equalTo(""));
+    }
+    
+    @Test
+    public void underscored_shouldReturnNullIfNullPassedIn() {
+    	assertThat(underscored(null), equalTo(null));
+    }
+
 }