TypeAlias<T>

src/main/java/net/kemitix/mon/TypeAlias.java

@@ -0,0 +1,75 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Paul Campbell
+ *
+ * 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 NONINFRINGEMENT. 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 net.kemitix.mon;
+
+/**
+ * Type Alias for other types.
+ *
+ * @param <T> the type of the alias
+ *
+ * @author Paul Campbell (pcampbell@kemitix.net)
+ */
+@SuppressWarnings("abstractclassname")
+public abstract class TypeAlias<T> {
+
+    /**
+     * The value.
+     */
+    private final T value;
+
+    /**
+     * Constructor.
+     *
+     * @param value the value
+     */
+    protected TypeAlias(final T value) {
+        this.value = value;
+    }
+
+    @Override
+    public final int hashCode() {
+        return value.hashCode();
+    }
+
+    @Override
+    public final boolean equals(final Object o) {
+        if (o instanceof TypeAlias) {
+            return value.equals(((TypeAlias) o).value);
+        }
+        return value.equals(o);
+    }
+
+    @Override
+    public final String toString() {
+        return value.toString();
+    }
+
+    /**
+     * Get the value of the type alias.
+     *
+     * @return the value
+     */
+    public final T getValue() {
+        return value;
+    }
+
+}

src/test/java/net/kemitix/mon/TypeAliasTest.java

@@ -0,0 +1,81 @@
+package net.kemitix.mon;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class TypeAliasTest {
+
+    @Test
+    public void shouldCreateATypeAliasAndGetTheValue() throws Exception {
+        //given
+        final String value = "value";
+        //when
+        final TypeAlias<String> typeAlias = new TypeAlias<String>(value) {
+        };
+        //then
+        assertThat(typeAlias.getValue()).isEqualTo(value);
+    }
+
+    @Test
+    public void shouldCreateAnAliasedTypeAndGetTheValue() throws Exception {
+        //given
+        final String value = "value";
+        //when
+        final AnAlias anAlias = AnAlias.of(value);
+        //then
+        assertThat(anAlias.getValue()).isEqualTo(value);
+    }
+
+    @Test
+    public void shouldBeEqualWhenValuesAreTheSame() throws Exception {
+        //given
+        final String value = "value";
+        final AnAlias anAlias1 = AnAlias.of(value);
+        final AnAlias anAlias2 = AnAlias.of(value);
+        //then
+        assertThat(anAlias1).isEqualTo(anAlias2);
+    }
+
+    @Test
+    public void shouldBeEqualToUnAliasedValue() throws Exception {
+        //given
+        final String value = "value";
+        final AnAlias anAlias = AnAlias.of(value);
+        //then
+        assertThat(anAlias).isEqualTo(value);
+    }
+
+    @Test
+    public void shouldHaveHashCodeOfValue() throws Exception {
+        //given
+        final String value = "value";
+        final AnAlias anAlias = AnAlias.of(value);
+        //then
+        assertThat(anAlias.hashCode()).isEqualTo(value.hashCode());
+    }
+
+    @Test
+    public void shouldHaveSameToStringAsAliasedType() throws Exception {
+        //given
+        final String value = "value";
+        final AnAlias anAlias = AnAlias.of(value);
+        assertThat(anAlias.toString()).isEqualTo(value.toString());
+    }
+
+    private static class AnAlias extends TypeAlias<String> {
+
+        /**
+         * Constructor.
+         *
+         * @param value the value
+         */
+        protected AnAlias(final String value) {
+            super(value);
+        }
+
+        static AnAlias of(final String value) {
+            return new AnAlias(value);
+        }
+    }
+}