add empty iterable/collection factory methods with fixed generic type, to ease interop with jmock

scarytom · scarytom · commit 2e7b1f2b5707 · 2012-06-18T22:53:45.000+01:00
diff --git a/hamcrest-library/src/main/java/org/hamcrest/collection/IsEmptyCollection.java b/hamcrest-library/src/main/java/org/hamcrest/collection/IsEmptyCollection.java
@@ -22,21 +22,38 @@ public void describeMismatchSafely(Collection<? extends E> item, Description mis
       mismatchDescription.appendValue(item);
     }
 
-  @Override
-  public void describeTo(Description description) {
+    @Override
+    public void describeTo(Description description) {
         description.appendText("an empty collection");
     }
 
-  /**
-   * Creates a matcher for {@link java.util.Collection}s matching examined collections whose <code>isEmpty</code>
-   * method returns <code>true</code>.
-   * <p/>
-   * For example:
-   * <pre>assertThat(new ArrayList&lt;String&gt;(), is(empty()))</pre>
-   * 
-   */
+    /**
+     * Creates a matcher for {@link java.util.Collection}s matching examined collections whose <code>isEmpty</code>
+     * method returns <code>true</code>.
+     * <p/>
+     * For example:
+     * <pre>assertThat(new ArrayList&lt;String&gt;(), is(empty()))</pre>
+     * 
+     */
     @Factory
     public static <E> Matcher<Collection<? extends E>> empty() {
         return new IsEmptyCollection<E>();
     }
+
+    /**
+     * Creates a matcher for {@link java.util.Collection}s matching examined collections whose <code>isEmpty</code>
+     * method returns <code>true</code>.
+     * <p/>
+     * For example:
+     * <pre>assertThat(new ArrayList&lt;String&gt;(), is(emptyCollectionOf(String.class)))</pre>
+     * 
+     * @param type
+     *     the type of the collection's content
+     */
+    @Factory
+    public static <E> Matcher<Collection<E>> emptyCollectionOf(Class<E> type) {
+        @SuppressWarnings({ "rawtypes", "unchecked" })
+        final Matcher<Collection<E>> result = (Matcher)empty();
+        return result;
+    }
 }
diff --git a/hamcrest-library/src/main/java/org/hamcrest/collection/IsEmptyIterable.java b/hamcrest-library/src/main/java/org/hamcrest/collection/IsEmptyIterable.java
@@ -35,4 +35,20 @@ public void describeTo(Description description) {
     public static <E> Matcher<Iterable<? extends E>> emptyIterable() {
         return new IsEmptyIterable<E>();
     }
+
+    /**
+     * Creates a matcher for {@link Iterable}s matching examined iterables that yield no items.
+     * <p/>
+     * For example:
+     * <pre>assertThat(new ArrayList&lt;String&gt;(), is(emptyIterableOf(String.class)))</pre>
+     * 
+     * @param type
+     *     the type of the iterable's content
+     */
+    @Factory
+    public static <E> Matcher<Iterable<E>> emptyIterableOf(Class<E> type) {
+        @SuppressWarnings({ "rawtypes", "unchecked" })
+        final Matcher<Iterable<E>> result = (Matcher)emptyIterable();
+        return result;
+    }
 }
diff --git a/hamcrest-unit-test/src/main/java/org/hamcrest/collection/IsEmptyCollectionTest.java b/hamcrest-unit-test/src/main/java/org/hamcrest/collection/IsEmptyCollectionTest.java
@@ -29,6 +29,12 @@ public void testHasAReadableDescription() {
         assertDescription("an empty collection", createMatcher());
     }
 
+    public void testCompiles() {
+        needs(IsEmptyCollection.emptyCollectionOf(String.class));
+    }
+
+    private void needs(@SuppressWarnings("unused") Matcher<Collection<String>> bar) { }
+    
     private static Collection<String> collectionOfValues() {
         return new ArrayList<String>(asList("one", "three"));
     }
diff --git a/hamcrest-unit-test/src/main/java/org/hamcrest/collection/IsEmptyIterableTest.java b/hamcrest-unit-test/src/main/java/org/hamcrest/collection/IsEmptyIterableTest.java
@@ -1,14 +1,13 @@
 package org.hamcrest.collection;
 
-import static org.hamcrest.collection.IsEmptyIterable.emptyIterable;
-
 import java.util.ArrayList;
 import java.util.Collection;
 
 import org.hamcrest.AbstractMatcherTest;
 import org.hamcrest.Matcher;
 
 import static java.util.Arrays.asList;
+import static org.hamcrest.collection.IsEmptyIterable.emptyIterable;
 
 public class IsEmptyIterableTest extends AbstractMatcherTest {
 
@@ -29,6 +28,12 @@ public void testHasAReadableDescription() {
         assertDescription("an empty iterable", createMatcher());
     }
 
+    public void testCompiles() {
+        needs(IsEmptyIterable.emptyIterableOf(String.class));
+    }
+
+    private void needs(@SuppressWarnings("unused") Matcher<Iterable<String>> bar) { }
+
     private static Collection<String> collectionOfValues() {
         return new ArrayList<String>(asList("one", "three"));
     }

Original file line number	Diff line number	Diff line change
`@@ -29,6 +29,12 @@ public void testHasAReadableDescription() {`
`29`	`29`	`assertDescription("an empty collection", createMatcher());`
`30`	`30`	`}`
`31`	`31`
	`32`	`+ public void testCompiles() {`
	`33`	`+ needs(IsEmptyCollection.emptyCollectionOf(String.class));`
	`34`	`+ }`
	`35`	`+`
	`36`	`+ private void needs(@SuppressWarnings("unused") Matcher<Collection<String>> bar) { }`
	`37`	`+`
`32`	`38`	`private static Collection<String> collectionOfValues() {`
`33`	`39`	`return new ArrayList<String>(asList("one", "three"));`
`34`	`40`	`}`