#242: ReverseIterable

src/main/java/org/cactoos/list/ReverseIterable.java

@@ -0,0 +1,67 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cactoos.list;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * Reverse iterator.
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Yegor Bugayenko (yegor256@gmail.com)
+ * @version $Id$
+ * @param <X> Type of item
+ * @see FilteredIterable
+ * @since 0.9
+ */
+public final class ReverseIterable<X> implements Iterable<X> {
+
+    /**
+     * Iterable.
+     */
+    private final Iterable<X> iterable;
+
+    /**
+     * Ctor.
+     * @param src Source iterable
+     */
+    public ReverseIterable(final Iterable<X> src) {
+        this.iterable = src;
+    }
+
+    @Override
+    public Iterator<X> iterator() {
+        final List<X> list = new LinkedList<>();
+        for (final X item : this.iterable) {
+            list.add(item);
+        }
+        Collections.reverse(list);
+        return list.iterator();
+    }
+
+}

src/test/java/org/cactoos/list/ReverseIterableTest.java

@@ -0,0 +1,55 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Yegor Bugayenko
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.cactoos.list;
+
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link ReverseIterable}.
+ * @author Yegor Bugayenko (yegor256@gmail.com)
+ * @version $Id$
+ * @since 0.9
+ * @checkstyle JavadocMethodCheck (500 lines)
+ */
+public final class ReverseIterableTest {
+
+    @Test
+    public void reversesIterable() {
+        MatcherAssert.assertThat(
+            "Can't reverse an iterable",
+            String.join(
+                " ",
+                new ReverseIterable<>(
+                    new ArrayAsIterable<>(
+                        "hello", "world", "dude"
+                    )
+                )
+            ),
+            Matchers.equalTo("dude world hello")
+        );
+    }
+
+}