SLF4J Cleanup

CompositeLogScrubber ctr arg guards & test.  Added documentation.

Author: jeremiahjstacey

src/main/java/org/owasp/esapi/logging/cleaning/CompositeLogScrubber.java

@@ -17,11 +17,26 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * LogScrubber implementation which performs iterative delegate to an ordered
+ * List of LogScrubbers. <br>
+ * The results of the delegate list of LogScrubbers is additive, meaning that
+ * the the original message is passed to the first delegate and its return value
+ * is passed to the second (etc). <br>
+ *
+ */
 public class CompositeLogScrubber  implements LogScrubber {
-
+    /** Delegate scrubbers.*/
     private final List<LogScrubber> messageCleaners;
 
+    /**
+     * Ctr.
+     * @param orderedCleaner Ordered List of delegate implementations.  Cannot be {@code null}
+     */
     public CompositeLogScrubber(List<LogScrubber> orderedCleaner) {
+        if (orderedCleaner == null) {
+            throw new IllegalArgumentException ("Delegate LogScrubber List cannot be null");
+        }
         this.messageCleaners = new ArrayList<>(orderedCleaner);
     }
 

src/test/java/org/owasp/esapi/logging/cleaning/CompositeLogScrubberTest.java

@@ -18,12 +18,26 @@
 import java.util.Arrays;
 
 import org.junit.Assert;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.mockito.Mockito;
 
 
 public class CompositeLogScrubberTest {
 
+    @Rule
+    public ExpectedException exEx = ExpectedException.none();
+    
+    @Test
+    public void testNullListThrowsException() {
+        exEx.expect(IllegalArgumentException.class);
+        exEx.expectMessage("cannot be null");
+        
+        new CompositeLogScrubber(null);
+    }
+    
+    
     @Test
     public void testPassthroughOnEmpty() {
         String str = "Testing Content";