yegor256#308 Equality

src/main/java/org/cactoos/scalar/Equality.java

@@ -0,0 +1,83 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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.scalar;
+
+import org.cactoos.Bytes;
+import org.cactoos.Scalar;
+
+/**
+ * Equality.
+ *
+ * <p>There is no thread-safety guarantee.
+ *
+ * @author Vedran Vatavuk (123vgv@gmail.com)
+ * @version $Id$
+ * @param <T> Type of result
+ * @since 0.30.1
+ */
+public final class Equality<T extends Bytes> implements Scalar<Integer> {
+
+    /**
+     * Left.
+     */
+    private final T left;
+
+    /**
+     * Right.
+     */
+    private final T right;
+
+    /**
+     * Ctor.
+     * @param lft Left
+     * @param rght Right
+     */
+    public Equality(final T lft, final T rght) {
+        this.left = lft;
+        this.right = rght;
+    }
+
+    @Override
+    public Integer value() throws Exception {
+        final byte[] lft = this.left.asBytes();
+        final byte[] rght = this.right.asBytes();
+        int result = 0;
+        final int max = Math.max(lft.length, rght.length);
+        for (int idx = 0; idx < max; ++idx) {
+            if (idx >= lft.length) {
+                result = -1;
+                break;
+            }
+            if (idx >= rght.length) {
+                result = 1;
+                break;
+            }
+            result = lft[idx] - rght[idx];
+            if (result != 0) {
+                break;
+            }
+        }
+        return (int) Math.signum(result);
+    }
+}

src/test/java/org/cactoos/scalar/EqualityTest.java

@@ -0,0 +1,121 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017-2018 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.scalar;
+
+import java.nio.ByteBuffer;
+import org.cactoos.Bytes;
+import org.hamcrest.MatcherAssert;
+import org.hamcrest.Matchers;
+import org.junit.Test;
+
+/**
+ * Test case for {@link Equality}.
+ * @author Vedran Vatavuk (123vgv@gmail.com)
+ * @version $Id$
+ * @since 0.30.1
+ * @checkstyle JavadocMethodCheck (500 lines)
+ * @checkstyle MagicNumberCheck (500 lines)
+ */
+public final class EqualityTest {
+
+    @Test
+    public void notEqualLeft() throws Exception {
+        MatcherAssert.assertThat(
+            new Equality<>(
+                new EqualityTest.Weight(0), new EqualityTest.Weight(500)
+            ).value(),
+            Matchers.equalTo(-1)
+        );
+    }
+
+    @Test
+    public void notEqualRight() throws Exception {
+        MatcherAssert.assertThat(
+            new Equality<>(
+                new EqualityTest.Weight(500), new EqualityTest.Weight(0)
+            ).value(),
+            Matchers.equalTo(1)
+        );
+    }
+
+    @Test
+    public void notEqualLeftWithSameSize() throws Exception {
+        MatcherAssert.assertThat(
+            new Equality<>(
+                new EqualityTest.Weight(400), new EqualityTest.Weight(500)
+            ).value(),
+            Matchers.equalTo(-1)
+        );
+    }
+
+    @Test
+    public void notEqualRightWithSameSize() throws Exception {
+        MatcherAssert.assertThat(
+            new Equality<>(
+                new EqualityTest.Weight(500), new EqualityTest.Weight(400)
+            ).value(),
+            Matchers.equalTo(1)
+        );
+    }
+
+    @Test
+    public void equal() throws Exception {
+        MatcherAssert.assertThat(
+            new Equality<>(
+                new EqualityTest.Weight(500), new EqualityTest.Weight(500)
+            ).value(),
+            Matchers.equalTo(0)
+        );
+    }
+
+    /**
+     * Weight.
+     */
+    private static final class Weight implements Bytes {
+
+        /**
+         * Kilos.
+         */
+        private final int kilos;
+
+        /**
+         * Ctor.
+         * @param kls Kilos
+         */
+        Weight(final int kls) {
+            this.kilos = kls;
+        }
+
+        @Override
+        public byte[] asBytes() {
+            return new UncheckedScalar<>(
+                new Ternary<>(
+                    this.kilos == 0,
+                    new byte[]{},
+                    ByteBuffer.allocate(4).putInt(this.kilos).array()
+                )
+            ).value();
+        }
+    }
+}