Adding composite specification (Issue#1093) (#1094)

* Resolution proposition to Issue#1055 (UML diagram left to do)

* Deciding not to modify the UML diagram for now

* Resolution proposition to Issue#1093

* Code reformatting

specification/src/main/java/com/iluwatar/specification/app/App.java

@@ -31,9 +31,10 @@ import com.iluwatar.specification.creature.Octopus;
 import com.iluwatar.specification.creature.Shark;
 import com.iluwatar.specification.creature.Troll;
 import com.iluwatar.specification.property.Color;
-import com.iluwatar.specification.property.Mass;
 import com.iluwatar.specification.property.Movement;
+import com.iluwatar.specification.selector.AbstractSelector;
 import com.iluwatar.specification.selector.ColorSelector;
+import com.iluwatar.specification.selector.MassEqualSelector;
 import com.iluwatar.specification.selector.MassGreaterThanSelector;
 import com.iluwatar.specification.selector.MassSmallerThanOrEqSelector;
 import com.iluwatar.specification.selector.MovementSelector;
@@ -77,13 +78,8 @@ public class App {
     List<Creature> darkCreatures =
         creatures.stream().filter(new ColorSelector(Color.DARK)).collect(Collectors.toList());
     darkCreatures.forEach(c -> LOGGER.info(c.toString()));
-    // find all red and flying creatures
-    LOGGER.info("Find all red and flying creatures");
-    List<Creature> redAndFlyingCreatures =
-        creatures.stream()
-            .filter(new ColorSelector(Color.RED).and(new MovementSelector(Movement.FLYING)))
-            .collect(Collectors.toList());
-    redAndFlyingCreatures.forEach(c -> LOGGER.info(c.toString()));
+
+    LOGGER.info("\n");
     // so-called "parameterized" specification
     LOGGER.info("Demonstrating parameterized specification :");
     // find all creatures heavier than 500kg
@@ -98,5 +94,26 @@ public class App {
         creatures.stream().filter(new MassSmallerThanOrEqSelector(500.0))
             .collect(Collectors.toList());
     lightCreatures.forEach(c -> LOGGER.info(c.toString()));
+
+    LOGGER.info("\n");
+    // so-called "composite" specification
+    LOGGER.info("Demonstrating composite specification :");
+    // find all red and flying creatures
+    LOGGER.info("Find all red and flying creatures");
+    List<Creature> redAndFlyingCreatures =
+        creatures.stream()
+            .filter(new ColorSelector(Color.RED).and(new MovementSelector(Movement.FLYING)))
+            .collect(Collectors.toList());
+    redAndFlyingCreatures.forEach(c -> LOGGER.info(c.toString()));
+    // find all creatures dark or red, non-swimming, and heavier than or equal to 400kg
+    LOGGER.info("Find all scary creatures");
+    AbstractSelector<Creature> scaryCreaturesSelector = new ColorSelector(Color.DARK)
+        .or(new ColorSelector(Color.RED)).and(new MovementSelector(Movement.SWIMMING).not())
+        .and(new MassGreaterThanSelector(400.0).or(new MassEqualSelector(400.0)));
+    List<Creature> scaryCreatures =
+        creatures.stream()
+            .filter(scaryCreaturesSelector)
+            .collect(Collectors.toList());
+    scaryCreatures.forEach(c -> LOGGER.info(c.toString()));
   }
 }

specification/src/main/java/com/iluwatar/specification/property/Mass.java

@@ -23,7 +23,9 @@
 
 package com.iluwatar.specification.property;
 
-/** Mass property. */
+/**
+ * Mass property.
+ */
 public class Mass {
 
   private double value;

specification/src/main/java/com/iluwatar/specification/selector/AbstractSelector.java

@@ -0,0 +1,44 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+import java.util.function.Predicate;
+
+/**
+ * Base class for selectors.
+ */
+public abstract class AbstractSelector<T> implements Predicate<T> {
+
+  public AbstractSelector<T> and(AbstractSelector<T> other) {
+    return new ConjunctionSelector<>(this, other);
+  }
+
+  public AbstractSelector<T> or(AbstractSelector<T> other) {
+    return new DisjunctionSelector<>(this, other);
+  }
+
+  public AbstractSelector<T> not() {
+    return new NegationSelector<>(this);
+  }
+}

specification/src/main/java/com/iluwatar/specification/selector/ColorSelector.java

@@ -25,12 +25,11 @@ package com.iluwatar.specification.selector;
 
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Color;
-import java.util.function.Predicate;
 
 /**
  * Color selector.
  */
-public class ColorSelector implements Predicate<Creature> {
+public class ColorSelector extends AbstractSelector<Creature> {
 
   private final Color color;
 

specification/src/main/java/com/iluwatar/specification/selector/ConjunctionSelector.java

@@ -0,0 +1,47 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+import java.util.List;
+
+/**
+ * A Selector defined as the conjunction (AND) of other (leaf) selectors.
+ */
+public class ConjunctionSelector<T> extends AbstractSelector<T> {
+
+  private List<AbstractSelector<T>> leafComponents;
+
+  @SafeVarargs
+  ConjunctionSelector(AbstractSelector<T>... selectors) {
+    this.leafComponents = List.of(selectors);
+  }
+
+  /**
+   * Tests if *all* selectors pass the test.
+   */
+  @Override
+  public boolean test(T t) {
+    return leafComponents.stream().allMatch(comp -> (comp.test(t)));
+  }
+}

specification/src/main/java/com/iluwatar/specification/selector/DisjunctionSelector.java

@@ -0,0 +1,47 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+import java.util.List;
+
+/**
+ * A Selector defined as the disjunction (OR) of other (leaf) selectors.
+ */
+public class DisjunctionSelector<T> extends AbstractSelector<T> {
+
+  private List<AbstractSelector<T>> leafComponents;
+
+  @SafeVarargs
+  DisjunctionSelector(AbstractSelector<T>... selectors) {
+    this.leafComponents = List.of(selectors);
+  }
+
+  /**
+   * Tests if *at least one* selector passes the test.
+   */
+  @Override
+  public boolean test(T t) {
+    return leafComponents.stream().anyMatch(comp -> comp.test(t));
+  }
+}

specification/src/main/java/com/iluwatar/specification/selector/MassEqualSelector.java

@@ -0,0 +1,47 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.property.Mass;
+
+/**
+ * Mass selector for values exactly equal than the parameter.
+ */
+public class MassEqualSelector extends AbstractSelector<Creature> {
+
+  private final Mass mass;
+
+  /**
+   * The use of a double as a parameter will spare some typing when instantiating this class.
+   */
+  public MassEqualSelector(double mass) {
+    this.mass = new Mass(mass);
+  }
+
+  @Override
+  public boolean test(Creature t) {
+    return t.getMass().equals(mass);
+  }
+}

specification/src/main/java/com/iluwatar/specification/selector/MassGreaterThanSelector.java

@@ -25,14 +25,17 @@ package com.iluwatar.specification.selector;
 
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Mass;
-import java.util.function.Predicate;
 
-/** Mass selector for values greater than the parameter. */
-public class MassGreaterThanSelector implements Predicate<Creature> {
+/**
+ * Mass selector for values greater than the parameter.
+ */
+public class MassGreaterThanSelector extends AbstractSelector<Creature> {
 
   private final Mass mass;
 
-  /** The use of a double as a parameter will spare some typing when instantiating this class. */
+  /**
+   * The use of a double as a parameter will spare some typing when instantiating this class.
+   */
   public MassGreaterThanSelector(double mass) {
     this.mass = new Mass(mass);
   }

specification/src/main/java/com/iluwatar/specification/selector/MassSmallerThanOrEqSelector.java

@@ -25,14 +25,17 @@ package com.iluwatar.specification.selector;
 
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Mass;
-import java.util.function.Predicate;
 
-/** Mass selector for values smaller or equal to the parameter. */
-public class MassSmallerThanOrEqSelector implements Predicate<Creature> {
+/**
+ * Mass selector for values smaller or equal to the parameter.
+ */
+public class MassSmallerThanOrEqSelector extends AbstractSelector<Creature> {
 
   private final Mass mass;
 
-  /** The use of a double as a parameter will spare some typing when instantiating this class. */
+  /**
+   * The use of a double as a parameter will spare some typing when instantiating this class.
+   */
   public MassSmallerThanOrEqSelector(double mass) {
     this.mass = new Mass(mass);
   }

specification/src/main/java/com/iluwatar/specification/selector/MovementSelector.java

@@ -25,12 +25,11 @@ package com.iluwatar.specification.selector;
 
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Movement;
-import java.util.function.Predicate;
 
 /**
  * Movement selector.
  */
-public class MovementSelector implements Predicate<Creature> {
+public class MovementSelector extends AbstractSelector<Creature> {
 
   private final Movement movement;
 

specification/src/main/java/com/iluwatar/specification/selector/NegationSelector.java

@@ -0,0 +1,46 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+
+/**
+ * A Selector defined as the negation (NOT) of a (leaf) selectors. This is of course only useful
+ * when used in combination with other composite selectors.
+ */
+public class NegationSelector<T> extends AbstractSelector<T> {
+
+  private AbstractSelector<T> component;
+
+  NegationSelector(AbstractSelector<T> selector) {
+    this.component = selector;
+  }
+
+  /**
+   * Tests if the selector fails the test (yes).
+   */
+  @Override
+  public boolean test(T t) {
+    return !(component.test(t));
+  }
+}

specification/src/main/java/com/iluwatar/specification/selector/SizeSelector.java

@@ -25,12 +25,11 @@ package com.iluwatar.specification.selector;
 
 import com.iluwatar.specification.creature.Creature;
 import com.iluwatar.specification.property.Size;
-import java.util.function.Predicate;
 
 /**
  * Size selector.
  */
-public class SizeSelector implements Predicate<Creature> {
+public class SizeSelector extends AbstractSelector<Creature> {
 
   private final Size size;
 

specification/src/test/java/com/iluwatar/specification/app/AppTest.java

@@ -26,9 +26,7 @@ package com.iluwatar.specification.app;
 import org.junit.jupiter.api.Test;
 
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 

specification/src/test/java/com/iluwatar/specification/creature/CreatureTest.java

@@ -23,18 +23,17 @@
 
 package com.iluwatar.specification.creature;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
 import com.iluwatar.specification.property.Color;
 import com.iluwatar.specification.property.Mass;
 import com.iluwatar.specification.property.Movement;
 import com.iluwatar.specification.property.Size;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
-
 import java.util.Collection;
 import java.util.List;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
 
 /**
  * Date: 12/29/15 - 7:47 PM
@@ -48,12 +47,18 @@ public class CreatureTest {
    */
   public static Collection<Object[]> dataProvider() {
     return List.of(
-            new Object[]{new Dragon(), "Dragon", Size.LARGE, Movement.FLYING, Color.RED, new Mass(39300.0)},
-            new Object[]{new Goblin(), "Goblin", Size.SMALL, Movement.WALKING, Color.GREEN, new Mass(30.0)},
-            new Object[]{new KillerBee(), "KillerBee", Size.SMALL, Movement.FLYING, Color.LIGHT, new Mass(6.7)},
-            new Object[]{new Octopus(), "Octopus", Size.NORMAL, Movement.SWIMMING, Color.DARK, new Mass(12.0)},
-            new Object[]{new Shark(), "Shark", Size.NORMAL, Movement.SWIMMING, Color.LIGHT, new Mass(500.0)},
-            new Object[]{new Troll(), "Troll", Size.LARGE, Movement.WALKING, Color.DARK, new Mass(4000.0)}
+        new Object[]{new Dragon(), "Dragon", Size.LARGE, Movement.FLYING, Color.RED,
+            new Mass(39300.0)},
+        new Object[]{new Goblin(), "Goblin", Size.SMALL, Movement.WALKING, Color.GREEN,
+            new Mass(30.0)},
+        new Object[]{new KillerBee(), "KillerBee", Size.SMALL, Movement.FLYING, Color.LIGHT,
+            new Mass(6.7)},
+        new Object[]{new Octopus(), "Octopus", Size.NORMAL, Movement.SWIMMING, Color.DARK,
+            new Mass(12.0)},
+        new Object[]{new Shark(), "Shark", Size.NORMAL, Movement.SWIMMING, Color.LIGHT,
+            new Mass(500.0)},
+        new Object[]{new Troll(), "Troll", Size.LARGE, Movement.WALKING, Color.DARK,
+            new Mass(4000.0)}
     );
   }
 
@@ -77,24 +82,28 @@ public class CreatureTest {
 
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testGetColor(Creature testedCreature, String name, Size size, Movement movement, Color color) {
+  public void testGetColor(Creature testedCreature, String name, Size size, Movement movement,
+      Color color) {
     assertEquals(color, testedCreature.getColor());
   }
 
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testGetMass(Creature testedCreature, String name, Size size, Movement movement, Color color, Mass mass) {
+  public void testGetMass(Creature testedCreature, String name, Size size, Movement movement,
+      Color color, Mass mass) {
     assertEquals(mass, testedCreature.getMass());
   }
 
   @ParameterizedTest
   @MethodSource("dataProvider")
-  public void testToString(Creature testedCreature, String name, Size size, Movement movement, Color color, Mass mass) {
+  public void testToString(Creature testedCreature, String name, Size size, Movement movement,
+      Color color, Mass mass) {
     final String toString = testedCreature.toString();
     assertNotNull(toString);
     assertEquals(
-            String.format("%s [size=%s, movement=%s, color=%s, mass=%s]", name, size, movement, color, mass),
-            toString
+        String.format("%s [size=%s, movement=%s, color=%s, mass=%s]", name, size, movement, color,
+            mass),
+        toString
     );
   }
 }

specification/src/test/java/com/iluwatar/specification/selector/ColorSelectorTest.java

@@ -23,15 +23,15 @@
 
 package com.iluwatar.specification.selector;
 
-import com.iluwatar.specification.creature.Creature;
-import com.iluwatar.specification.property.Color;
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.property.Color;
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/29/15 - 7:35 PM
  *

specification/src/test/java/com/iluwatar/specification/selector/CompositeSelectorsTest.java

@@ -0,0 +1,93 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.specification.selector;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.property.Mass;
+import com.iluwatar.specification.property.Movement;
+import org.junit.jupiter.api.Test;
+
+public class CompositeSelectorsTest {
+
+  /**
+   * Verify if the conjunction selector gives the correct results.
+   */
+  @Test
+  public void testAndComposition() {
+    final Creature swimmingHeavyCreature = mock(Creature.class);
+    when(swimmingHeavyCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingHeavyCreature.getMass()).thenReturn(new Mass(100.0));
+
+    final Creature swimmingLightCreature = mock(Creature.class);
+    when(swimmingLightCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingLightCreature.getMass()).thenReturn(new Mass(25.0));
+
+    final AbstractSelector<Creature> lightAndSwimmingSelector = new MassSmallerThanOrEqSelector(
+        50.0).and(new MovementSelector(Movement.SWIMMING));
+    assertFalse(lightAndSwimmingSelector.test(swimmingHeavyCreature));
+    assertTrue(lightAndSwimmingSelector.test(swimmingLightCreature));
+  }
+
+  /**
+   * Verify if the disjunction selector gives the correct results.
+   */
+  @Test
+  public void testOrComposition() {
+    final Creature swimmingHeavyCreature = mock(Creature.class);
+    when(swimmingHeavyCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingHeavyCreature.getMass()).thenReturn(new Mass(100.0));
+
+    final Creature swimmingLightCreature = mock(Creature.class);
+    when(swimmingLightCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingLightCreature.getMass()).thenReturn(new Mass(25.0));
+
+    final AbstractSelector<Creature> lightOrSwimmingSelector = new MassSmallerThanOrEqSelector(50.0)
+        .or(new MovementSelector(Movement.SWIMMING));
+    assertTrue(lightOrSwimmingSelector.test(swimmingHeavyCreature));
+    assertTrue(lightOrSwimmingSelector.test(swimmingLightCreature));
+  }
+
+  /**
+   * Verify if the negation selector gives the correct results.
+   */
+  @Test
+  public void testNotComposition() {
+    final Creature swimmingHeavyCreature = mock(Creature.class);
+    when(swimmingHeavyCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingHeavyCreature.getMass()).thenReturn(new Mass(100.0));
+
+    final Creature swimmingLightCreature = mock(Creature.class);
+    when(swimmingLightCreature.getMovement()).thenReturn(Movement.SWIMMING);
+    when(swimmingLightCreature.getMass()).thenReturn(new Mass(25.0));
+
+    final AbstractSelector<Creature> heavySelector = new MassSmallerThanOrEqSelector(50.0).not();
+    assertTrue(heavySelector.test(swimmingHeavyCreature));
+    assertFalse(heavySelector.test(swimmingLightCreature));
+  }
+}

specification/src/test/java/com/iluwatar/specification/selector/MassSelectorTest.java

@@ -34,7 +34,9 @@ import org.junit.jupiter.api.Test;
 
 public class MassSelectorTest {
 
-  /** Verify if the mass selector gives the correct results */
+  /**
+   * Verify if the mass selector gives the correct results.
+   */
   @Test
   public void testMass() {
     final Creature lightCreature = mock(Creature.class);

specification/src/test/java/com/iluwatar/specification/selector/MovementSelectorTest.java

@@ -23,15 +23,15 @@
 
 package com.iluwatar.specification.selector;
 
-import com.iluwatar.specification.creature.Creature;
-import com.iluwatar.specification.property.Movement;
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.property.Movement;
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/29/15 - 7:37 PM
  *
@@ -40,7 +40,7 @@ import static org.mockito.Mockito.when;
 public class MovementSelectorTest {
 
   /**
-   * Verify if the movement selector gives the correct results
+   * Verify if the movement selector gives the correct results.
    */
   @Test
   public void testMovement() {

specification/src/test/java/com/iluwatar/specification/selector/SizeSelectorTest.java

@@ -23,15 +23,15 @@
 
 package com.iluwatar.specification.selector;
 
-import com.iluwatar.specification.creature.Creature;
-import com.iluwatar.specification.property.Size;
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
+import com.iluwatar.specification.creature.Creature;
+import com.iluwatar.specification.property.Size;
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/29/15 - 7:43 PM
  *