cleanup

src/main/java/difflib/DiffUtils.java

@@ -29,6 +29,7 @@ import difflib.patch.PatchFailedException;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Objects;
 import static java.util.stream.Collectors.joining;
 
 /**
@@ -85,15 +86,10 @@ public final class DiffUtils {
      */
     public static <T> Patch<T> diff(List<T> original, List<T> revised,
             DiffAlgorithm<T> algorithm) throws DiffException {
-        if (original == null) {
-            throw new IllegalArgumentException("original must not be null");
-        }
-        if (revised == null) {
-            throw new IllegalArgumentException("revised must not be null");
-        }
-        if (algorithm == null) {
-            throw new IllegalArgumentException("algorithm must not be null");
-        }
+        Objects.requireNonNull(original,"original must not be null");
+        Objects.requireNonNull(revised,"revised must not be null");
+        Objects.requireNonNull(algorithm,"algorithm must not be null");
+        
         return algorithm.diff(original, revised);
     }
 

src/main/java/difflib/algorithm/myers/MyersDiff.java

@@ -32,6 +32,7 @@ import java.lang.reflect.Array;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * A clean-room implementation of <a href="http://www.cs.arizona.edu/people/gene/">
@@ -97,12 +98,9 @@ public final class MyersDiff<T> implements DiffAlgorithm<T> {
      */
     @Override
     public Patch<T> diff(final List<T> original, final List<T> revised) throws DiffException {
-        if (original == null) {
-            throw new IllegalArgumentException("original list must not be null");
-        }
-        if (revised == null) {
-            throw new IllegalArgumentException("revised list must not be null");
-        }
+        Objects.requireNonNull(original, "original list must not be null");
+        Objects.requireNonNull(revised, "revised list must not be null");
+        
         PathNode path = buildPath(original, revised);
         return buildRevision(path, original, revised);
     }
@@ -118,12 +116,8 @@ public final class MyersDiff<T> implements DiffAlgorithm<T> {
      */
     private PathNode buildPath(final List<T> orig, final List<T> rev)
             throws DifferentiationFailedException {
-        if (orig == null) {
-            throw new IllegalArgumentException("original sequence is null");
-        }
-        if (rev == null) {
-            throw new IllegalArgumentException("revised sequence is null");
-        }
+        Objects.requireNonNull(orig, "original sequence is null");
+        Objects.requireNonNull(rev, "revised sequence is null");
 
         // these are local constants
         final int N = orig.size();
@@ -192,15 +186,9 @@ public final class MyersDiff<T> implements DiffAlgorithm<T> {
      * path.
      */
     private Patch<T> buildRevision(PathNode path, List<T> orig, List<T> rev) {
-        if (path == null) {
-            throw new IllegalArgumentException("path is null");
-        }
-        if (orig == null) {
-            throw new IllegalArgumentException("original sequence is null");
-        }
-        if (rev == null) {
-            throw new IllegalArgumentException("revised sequence is null");
-        }
+        Objects.requireNonNull(path, "path is null");
+        Objects.requireNonNull(orig, "original sequence is null");
+        Objects.requireNonNull(rev, "revised sequence is null");
 
         Patch<T> patch = new Patch<>();
         if (path.isSnake()) {

src/test/java/difflib/text/DiffRowGeneratorTest.java

@@ -187,4 +187,24 @@ public class DiffRowGeneratorTest {
         assertEquals(4, list.size());
         assertEquals("[test, ,, test2, ,]", list.toString());
     }
+    
+    
+    @Test
+    public void testGeneratorExample1() throws DiffException {
+        DiffRowGenerator generator = DiffRowGenerator.create()
+                .showInlineDiffs(true)
+                .mergeOriginalRevised(true)
+                .inlineDiffByWord(true)
+                .oldTag(f -> "~")
+                .newTag(f -> "**")
+                .build();
+        List<DiffRow> rows = generator.generateDiffRows(
+                Arrays.asList("This is a test senctence."),
+                Arrays.asList("This is a test for diffutils."));
+        
+        System.out.println(rows.get(0).getOldLine());        
+        
+        assertEquals(1, rows.size());
+        assertEquals("This is a test ~senctence~**for diffutils**.", rows.get(0).getOldLine());
+    }
 }