ordering work

Eugen Paraschiv · Eugen Paraschiv · commit b19a5af15649 · 2013-10-25T12:01:33.000+03:00
diff --git a/guava/src/test/java/org/baeldung/guava/collections/GuavaOrderingExamplesTest.java b/guava/src/test/java/org/baeldung/guava/collections/GuavaOrderingExamplesTest.java
@@ -1,56 +1,81 @@
 package org.baeldung.guava.collections;
 
-import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
 import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
 
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
 import org.junit.Test;
 
+import com.google.common.collect.Lists;
 import com.google.common.collect.Ordering;
 import com.google.common.primitives.Ints;
 
 public class GuavaOrderingExamplesTest {
 
+    private final class OrderingByLenght extends Ordering<String> {
+        @Override
+        public final int compare(final String s1, final String s2) {
+            return Ints.compare(s1.length(), s2.length());
+        }
+    }
+
     // tests
 
     @Test
     public final void givenCollectionWithNulls_whenSortingWithNullsLast_thenNullsAreLast() {
-        final List<Integer> nums = Arrays.asList(3, 5, 4, null, 1, 2);
-        Collections.sort(nums, Ordering.natural().nullsLast());
-        assertThat(nums.get(nums.size() - 1), nullValue());
+        final List<Integer> toSort = Arrays.asList(3, 5, 4, null, 1, 2);
+        Collections.sort(toSort, Ordering.natural().nullsLast());
+        assertThat(toSort.get(toSort.size() - 1), nullValue());
     }
 
     @Test
     public final void givenCollectionWithNulls_whenSortingWithNullsFirst_thenNullsAreFirst() {
-        final List<Integer> nums = Arrays.asList(3, 5, 4, null, 1, 2);
-        Collections.sort(nums, Ordering.natural().nullsFirst());
-        assertThat(nums.get(0), nullValue());
+        final List<Integer> toSort = Arrays.asList(3, 5, 4, null, 1, 2);
+        Collections.sort(toSort, Ordering.natural().nullsFirst());
+        assertThat(toSort.get(0), nullValue());
     }
 
     @Test
     public final void whenCollectionIsSortedNullsLastReversed_thenNullAreFirst() {
-        final List<Integer> nums = Arrays.asList(3, 5, 4, null, 1, 2);
-        Collections.sort(nums, Ordering.natural().nullsLast().reverse());
-        assertThat(nums.get(0), nullValue());
+        final List<Integer> toSort = Arrays.asList(3, 5, 4, null, 1, 2);
+        Collections.sort(toSort, Ordering.natural().nullsLast().reverse());
+        assertThat(toSort.get(0), nullValue());
+    }
+
+    @Test
+    public final void givenCollectionIsSorted_whenUsingOrderingApiToCheckOrder_thenCheckCanBePerformed() {
+        final List<String> toSort = Arrays.asList("zz", "aa", "b", "ccc");
+        final Ordering<String> byLength = new OrderingByLenght();
+        Collections.sort(toSort, byLength);
+
+        final Ordering<String> expectedOrder = Ordering.explicit(Lists.newArrayList("b", "zz", "aa", "ccc"));
+        assertTrue(expectedOrder.isOrdered(toSort));
     }
 
     @Test
     public final void whenSortingCollectionsOfStringsByLenght_thenCorrectlySorted() {
-        final List<String> toSort = Arrays.asList("aa", "b", null, "ccc");
-        final Ordering<String> byLength = new Ordering<String>() {
-            @Override
-            public int compare(final String s1, final String s2) {
-                return Ints.compare(s1.length(), s2.length());
-            }
-        };
-
-        Collections.sort(toSort, byLength.nullsFirst());
-        assertThat(toSort.get(0), nullValue());
-        assertThat(toSort.get(1), equalTo("b"));
+        final List<String> toSort = Arrays.asList("zz", "aa", "b", "ccc");
+        final Ordering<String> byLength = new OrderingByLenght();
+
+        Collections.sort(toSort, byLength);
+
+        final Ordering<String> expectedOrder = Ordering.explicit(Lists.newArrayList("b", "zz", "aa", "ccc"));
+        assertTrue(expectedOrder.isOrdered(toSort));
+    }
+
+    @Test
+    public final void whenSortingCollectionsOfStringsByLenghtWithSecondaryNaturalOrdering_thenCorrectlySorted() {
+        final List<String> toSort = Arrays.asList("zz", "aa", "b", "ccc");
+        final Ordering<String> byLength = new OrderingByLenght();
+
+        Collections.sort(toSort, byLength.compound(Ordering.natural()));
+
+        final Ordering<String> expectedOrder = Ordering.explicit(Lists.newArrayList("b", "aa", "zz", "ccc"));
+        assertTrue(expectedOrder.isOrdered(toSort));
     }
 
 }
