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;