BAEL-16653 (#7691)

* added module 'design-patterns-behavioral'

* added module 'design-patterns-structural'

* added module 'design-patterns-creational'

* added module 'design-patterns-architectural'

* added module 'design-patterns-functional'

* moved facade code examples from design-patterns to design-patterns-structural

* moved singleton examples from design-patterns to design-patterns-creational

* moved bridge examples from design-patterns to design-patterns-structural

* moved creational examples from design-patterns to design-patterns-creational

* moved observer examples from design-patterns to design-patterns-behavioral

* moved flyweight examples from design-patterns to design-patterns-creational

* moved service locator examples from design-patterns to design-patterns-architectural

* moved double checked locking singleton examples from design-patterns to design-patterns-creational

* moved composite examples from design-patterns to design-patterns-structural

* moved visitor examples from design-patterns to design-patterns-behavioral

* moved dao examples from design-patterns to design-patterns-architectural

* moved interpreter examples from design-patterns to design-patterns-behavioral

* moved state examples from design-patterns to design-patterns-behavioral

* moved decorator examples from design-patterns to design-patterns-structural

* renamed LogerUtil to LoggerUtil

* moved template method examples from design-patterns to design-patterns-behavioral

* moved chain of responsibility examples from design-patterns to design-patterns-behavioral

* moved command examples from design-patterns to design-patterns-behavioral

* moved constructor vs static factory method examples from design-patterns to design-patterns-creational

* moved adapter examples from design-patterns to design-patterns-structural

* moved currying examples from design-patterns to design-patterns-functional

* moved proxy examples from design-patterns to design-patterns-structural

* moved persistence.xml from design-patterns to design-patterns-architectural

* deleted empty module: design-patterns

* moved mediator examples from design-patterns-2 to design-patterns-behavioral

* moved null object examples from design-patterns-2 to design-patterns-behavioral

* moved null check examples from design-patterns to design-patterns-behavioral

* moved freebuilder examples from design-patterns-2 to design-patterns-creational

* added module design-patterns-behavioral-2

* moved memento examples from design-patterns-2 to design-patterns-behavioral-2

* removed empty module design-patterns-2

* changed http to https in readmes in modules design-patterns-*

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/AdapterPatternDriver.java

@@ -0,0 +1,20 @@
+package com.baeldung.adapter;
+
+import static com.baeldung.util.LoggerUtil.LOG;
+
+public class AdapterPatternDriver {
+    
+    public static void main(String args[]) {
+    	Movable bugattiVeyron = new BugattiVeyron();
+    	MovableAdapter bugattiVeyronAdapter = new MovableAdapterImpl(bugattiVeyron);
+        LOG.info("Bugatti Veyron Super Sport's top speed is " + bugattiVeyronAdapter.getSpeed() + " Kmph.");
+
+        Movable mcLaren = new McLaren();
+        MovableAdapter mcLarenAdapter = new MovableAdapterImpl(mcLaren);
+        LOG.info("McLaren F1 top speed is " + mcLarenAdapter.getSpeed() + " Kmph.");
+
+        Movable astonMartin = new AstonMartin();
+        MovableAdapter astonMartinAdapter = new MovableAdapterImpl(astonMartin);
+        LOG.info("McLaren F1 top speed is " + astonMartinAdapter.getSpeed() + " Kmph.");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/AstonMartin.java

@@ -0,0 +1,8 @@
+package com.baeldung.adapter;
+
+public class AstonMartin implements Movable {
+    @Override
+    public double getSpeed() {
+        return 220;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/BugattiVeyron.java

@@ -0,0 +1,8 @@
+package com.baeldung.adapter;
+
+public class BugattiVeyron implements Movable {
+    @Override
+    public double getSpeed() {
+        return 268;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/McLaren.java

@@ -0,0 +1,8 @@
+package com.baeldung.adapter;
+
+public class McLaren implements Movable {
+    @Override
+    public double getSpeed() {
+        return 241;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/Movable.java

@@ -0,0 +1,6 @@
+package com.baeldung.adapter;
+
+public interface Movable {
+    // returns speed in MPH 
+    double getSpeed();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/MovableAdapter.java

@@ -0,0 +1,6 @@
+package com.baeldung.adapter;
+
+public interface MovableAdapter {
+    // returns speed in KMPH 
+    double getSpeed();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/adapter/MovableAdapterImpl.java

@@ -0,0 +1,19 @@
+package com.baeldung.adapter;
+
+public class MovableAdapterImpl implements MovableAdapter {
+    private Movable luxuryCars;
+    
+    public MovableAdapterImpl(Movable luxuryCars) {
+        this.luxuryCars = luxuryCars;
+    }
+
+    @Override
+    public double getSpeed() {
+        double mph = luxuryCars.getSpeed();
+        return convertMPHtoKMPH(mph);
+    }
+    
+    private double convertMPHtoKMPH(double mph) {
+        return mph * 1.60934;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Blue.java

@@ -0,0 +1,8 @@
+package com.baeldung.bridge;
+
+public class Blue implements Color {
+    @Override
+    public String fill() {
+        return "Color is Blue";
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/BridgePatternDriver.java

@@ -0,0 +1,14 @@
+package com.baeldung.bridge;
+
+public class BridgePatternDriver {
+
+    public static void main(String[] args) {
+        //a square with red color
+        Shape square = new Square(new Red());
+        System.out.println(square.draw());
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        System.out.println(triangle.draw());
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Color.java

@@ -0,0 +1,5 @@
+package com.baeldung.bridge;
+
+public interface Color {
+    String fill();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Red.java

@@ -0,0 +1,10 @@
+package com.baeldung.bridge;
+
+public class Red implements Color {
+
+    @Override
+    public String fill() {
+        return "Color is Red";
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Shape.java

@@ -0,0 +1,11 @@
+package com.baeldung.bridge;
+
+public abstract class Shape {
+    protected Color color;
+    
+    public Shape(Color color) {
+        this.color = color;
+    }
+    
+    abstract public String draw();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Square.java

@@ -0,0 +1,13 @@
+package com.baeldung.bridge;
+
+public class Square extends Shape {
+
+    public Square(Color color) {
+        super(color);
+    }
+
+    @Override
+    public String draw() {
+        return "Square drawn. " + color.fill();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/bridge/Triangle.java

@@ -0,0 +1,13 @@
+package com.baeldung.bridge;
+
+public class Triangle extends Shape {
+
+    public Triangle(Color color) {
+        super(color);
+    }
+
+    @Override
+    public String draw() {
+        return "Triangle drawn. "+ color.fill();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/composite/CompositeDemo.java

@@ -0,0 +1,19 @@
+package com.baeldung.composite;
+
+/**
+ * Created by Gebruiker on 5/3/2018.
+ */
+public class CompositeDemo {
+
+    public static void main(String args[]) {
+        Department salesDepartment = new SalesDepartment(1, "Sales department");
+        Department financialDepartment = new FinancialDepartment(2, "Financial department");
+
+        HeadDepartment headDepartment = new HeadDepartment(3, "Head department");
+
+        headDepartment.addDepartMent(salesDepartment);
+        headDepartment.addDepartMent(financialDepartment);
+
+        headDepartment.printDepartmentName();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/composite/Department.java

@@ -0,0 +1,9 @@
+package com.baeldung.composite;
+
+/**
+ * Created by Gebruiker on 5/1/2018.
+ */
+public interface Department {
+
+    void printDepartmentName();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/composite/FinancialDepartment.java

@@ -0,0 +1,35 @@
+package com.baeldung.composite;
+
+/**
+ * Created by Gebruiker on 5/1/2018.
+ */
+public class FinancialDepartment implements Department {
+
+    private Integer id;
+    private String name;
+
+    public FinancialDepartment(Integer id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public void printDepartmentName() {
+        System.out.println(getClass().getSimpleName());
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/composite/HeadDepartment.java

@@ -0,0 +1,33 @@
+package com.baeldung.composite;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by Gebruiker on 5/1/2018.
+ */
+public class HeadDepartment implements Department {
+
+    private Integer id;
+    private String name;
+
+    private List<Department> childDepartments;
+
+    public HeadDepartment(Integer id, String name) {
+        this.id = id;
+        this.name = name;
+        this.childDepartments = new ArrayList<Department>();
+    }
+
+    public void printDepartmentName() {
+        childDepartments.forEach(Department::printDepartmentName);
+    }
+
+    public void addDepartMent(Department department) {
+        childDepartments.add(department);
+    }
+
+    public void removeDepartment(Department department) {
+        childDepartments.remove(department);
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/composite/SalesDepartment.java

@@ -0,0 +1,35 @@
+package com.baeldung.composite;
+
+/**
+ * Created by Gebruiker on 5/1/2018.
+ */
+public class SalesDepartment implements Department {
+
+    private Integer id;
+    private String name;
+
+    public SalesDepartment(Integer id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public void printDepartmentName() {
+        System.out.println(getClass().getSimpleName());
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/BubbleLights.java

@@ -0,0 +1,16 @@
+package com.baeldung.decorator;
+
+public class BubbleLights extends TreeDecorator {
+
+    public BubbleLights(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithBubbleLights();
+    }
+    
+    private String decorateWithBubbleLights() {
+        return " with Bubble Lights";
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/ChristmasTree.java

@@ -0,0 +1,5 @@
+package com.baeldung.decorator;
+
+public interface ChristmasTree {
+    String decorate();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/ChristmasTreeImpl.java

@@ -0,0 +1,10 @@
+package com.baeldung.decorator;
+
+public class ChristmasTreeImpl implements ChristmasTree {
+
+    @Override
+    public String decorate() {
+        return "Christmas tree";
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/DecoratorPatternDriver.java

@@ -0,0 +1,18 @@
+package com.baeldung.decorator;
+
+import static com.baeldung.util.LoggerUtil.LOG;
+
+public class DecoratorPatternDriver {
+
+    public static void main(String[] args) {
+        // christmas tree with just one Garland
+        ChristmasTree tree1 = new Garland(new ChristmasTreeImpl());
+        LOG.info(tree1.decorate());
+
+        // christmas tree with two Garlands and one Bubble lights
+        ChristmasTree tree2 = new BubbleLights(new Garland(new Garland(new ChristmasTreeImpl())));
+        LOG.info(tree2.decorate());
+
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/Garland.java

@@ -0,0 +1,16 @@
+package com.baeldung.decorator;
+
+public class Garland extends TreeDecorator {
+
+    public Garland(ChristmasTree tree) {
+        super(tree);
+    }
+    
+    public String decorate() {
+        return super.decorate() + decorateWithGarland();
+    }
+
+    private String decorateWithGarland() {
+        return " with Garland";
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/decorator/TreeDecorator.java

@@ -0,0 +1,15 @@
+package com.baeldung.decorator;
+
+public abstract class TreeDecorator implements ChristmasTree {
+    private ChristmasTree tree;
+    
+    public TreeDecorator(ChristmasTree tree) {
+        this.tree = tree;
+    }
+    
+    @Override
+    public String decorate() {
+        return tree.decorate();
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/CarEngineFacade.java

@@ -0,0 +1,32 @@
+package com.baeldung.facade;
+
+import com.baeldung.facade.carsystem.*;
+
+public class CarEngineFacade {
+    private static final Integer DEFAULT_COOLING_TEMP = 90;
+    private static final Integer MAX_ALLOWED_TEMP = 50;
+    private FuelInjector fuelInjector = new FuelInjector();
+    private AirFlowController airFlowController = new AirFlowController();
+    private Starter starter = new Starter();
+    private CoolingController coolingController = new CoolingController();
+    private CatalyticConverter catalyticConverter = new CatalyticConverter();
+
+    public void startEngine(){
+        fuelInjector.on();
+        airFlowController.takeAir();
+        fuelInjector.on();
+        fuelInjector.inject();
+        starter.start();
+        coolingController.setTemperatureUpperLimit(DEFAULT_COOLING_TEMP);
+        coolingController.run();
+        catalyticConverter.on();
+    }
+
+    public void stopEngine(){
+        fuelInjector.off();
+        catalyticConverter.off();
+        coolingController.cool(MAX_ALLOWED_TEMP);
+        coolingController.stop();
+        airFlowController.off();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/AirFlowController.java

@@ -0,0 +1,19 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class AirFlowController {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(AirFlowController.class);
+    private AirFlowMeter airFlowMeter = new AirFlowMeter();
+
+    public void takeAir() {
+        airFlowMeter.getMeasurements();
+        LOGGER.info("Air provided!");
+    }
+
+    public void off() {
+        LOGGER.info("Air controller switched off.");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/AirFlowMeter.java

@@ -0,0 +1,13 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class AirFlowMeter {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(AirFlowMeter.class);
+
+    public void getMeasurements() {
+        LOGGER.info("Getting air measurements..");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/CatalyticConverter.java

@@ -0,0 +1,17 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CatalyticConverter {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(CatalyticConverter.class);
+
+    public void on() {
+        LOGGER.info("Catalytic Converter switched on!");
+    }
+
+    public void off() {
+        LOGGER.info("Catalytic Converter switched off!");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/CoolingController.java

@@ -0,0 +1,34 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CoolingController {
+    private static final Logger LOGGER = LoggerFactory.getLogger(CoolingController.class);
+    private static final Integer DEFAULT_RADIATOR_SPEED = 10;
+
+    private Integer temperatureUpperLimit;
+    private Radiator radiator = new Radiator();
+    private TemperatureSensor temperatureSensor = new TemperatureSensor();
+
+    public void setTemperatureUpperLimit(Integer temperatureUpperLimit) {
+        LOGGER.info("Setting temperature upper limit to {}", temperatureUpperLimit);
+        this.temperatureUpperLimit = temperatureUpperLimit;
+    }
+
+    public void run() {
+        LOGGER.info("Cooling Controller ready!");
+        radiator.setSpeed(DEFAULT_RADIATOR_SPEED);
+    }
+
+    public void cool(Integer maxAllowedTemp) {
+        LOGGER.info("Scheduled cooling with maximum allowed temperature {}", maxAllowedTemp);
+        temperatureSensor.getTemperature();
+        radiator.on();
+    }
+
+    public void stop() {
+        LOGGER.info("Stopping Cooling Controller..");
+        radiator.off();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/FuelInjector.java

@@ -0,0 +1,23 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FuelInjector {
+    private static final Logger LOGGER = LoggerFactory.getLogger(FuelInjector.class);
+
+    private FuelPump fuelPump = new FuelPump();
+
+    public void on(){
+        LOGGER.info("Fuel injector ready to inject fuel.");
+    }
+
+    public void inject() {
+        fuelPump.pump();
+        LOGGER.info("Fuel injected.");
+    }
+
+    public void off() {
+        LOGGER.info("Stopping Fuel injector..");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/FuelPump.java

@@ -0,0 +1,13 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FuelPump {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(FuelPump.class);
+
+    public void pump() {
+        LOGGER.info("Fuel Pump is pumping fuel..");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/Radiator.java

@@ -0,0 +1,21 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Radiator {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(Radiator.class);
+
+    public void on(){
+        LOGGER.info("Radiator switched on!");
+    }
+
+    public void off(){
+        LOGGER.info("Radiator switched off!");
+    }
+
+    public void setSpeed(Integer speed){
+        LOGGER.info("Setting radiator speed to {}",speed);
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/Starter.java

@@ -0,0 +1,13 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Starter {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(Starter.class);
+
+    public void start() {
+        LOGGER.info("Starting..");
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/facade/carsystem/TemperatureSensor.java

@@ -0,0 +1,13 @@
+package com.baeldung.facade.carsystem;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class TemperatureSensor {
+    private static final Logger LOGGER = LoggerFactory.getLogger(TemperatureSensor.class);
+
+    public void getTemperature(){
+        LOGGER.info("Getting temperature from the sensor..");
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/proxy/ExpensiveObject.java

@@ -0,0 +1,5 @@
+package com.baeldung.proxy;
+
+public interface ExpensiveObject {
+    void process();
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/proxy/ExpensiveObjectImpl.java

@@ -0,0 +1,20 @@
+package com.baeldung.proxy;
+
+import static com.baeldung.util.LoggerUtil.LOG;
+
+public class ExpensiveObjectImpl implements ExpensiveObject {
+
+    public ExpensiveObjectImpl() {
+        heavyInitialConfiguration();
+    }
+
+    @Override
+    public void process() {
+        LOG.info("processing complete.");
+    }
+
+    private void heavyInitialConfiguration() {
+        LOG.info("Loading initial configuration..");
+    }
+
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/proxy/ExpensiveObjectProxy.java

@@ -0,0 +1,13 @@
+package com.baeldung.proxy;
+
+public class ExpensiveObjectProxy implements ExpensiveObject{
+    private static ExpensiveObject object;
+
+    @Override
+    public void process() {
+        if(object == null) {
+            object = new ExpensiveObjectImpl();
+        }
+        object.process();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/proxy/ProxyPatternDriver.java

@@ -0,0 +1,9 @@
+package com.baeldung.proxy;
+
+public class ProxyPatternDriver {
+    public static void main(String[] args) {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+    }
+}

patterns/design-patterns-structural/src/main/java/com/baeldung/util/LoggerUtil.java

@@ -0,0 +1,35 @@
+package com.baeldung.util;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Properties;
+
+import org.apache.log4j.Logger;
+import org.apache.log4j.PropertyConfigurator;
+
+public class LoggerUtil {
+
+    public final static Logger LOG = Logger.getLogger("GLOBAL");
+    
+    static {
+    	configuration();
+    }
+    
+    private static void configuration() {
+    	Properties props = new Properties();
+    	try {
+			props.load(
+			  new BufferedReader(
+			    new InputStreamReader(
+			      LoggerUtil.class.getResourceAsStream("/log4jstructuraldp.properties")
+			    )
+			  )
+			);
+		} catch (IOException e) {
+			System.out.println("log4jstructuraldp.properties file not configured properly");
+			System.exit(0);
+		}
+    	PropertyConfigurator.configure(props);
+    }
+}

patterns/design-patterns-structural/src/main/resources/log4jstructuraldp.properties

@@ -0,0 +1,9 @@
+
+# Root logger 
+log4j.rootLogger=INFO, file, stdout
+
+# Write to console
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.Target=System.out
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

patterns/design-patterns-structural/src/test/java/com/baeldung/adapter/AdapterPatternIntegrationTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.adapter;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class AdapterPatternIntegrationTest {
+    @Test
+    public void givenMovableAdapter_WhenConvertingMPHToKMPH_thenSuccessfullyConverted() {
+        Movable bugattiVeyron = new BugattiVeyron();
+        MovableAdapter bugattiVeyronAdapter = new MovableAdapterImpl(bugattiVeyron);
+        assertEquals(bugattiVeyronAdapter.getSpeed(), 431.30312, 0.00001);
+
+        Movable mcLaren = new McLaren();
+        MovableAdapter mcLarenAdapter = new MovableAdapterImpl(mcLaren);
+        assertEquals(mcLarenAdapter.getSpeed(), 387.85094, 0.00001);
+
+        Movable astonMartin = new AstonMartin();
+        MovableAdapter astonMartinAdapter = new MovableAdapterImpl(astonMartin);
+        assertEquals(astonMartinAdapter.getSpeed(), 354.0548, 0.00001);
+    }
+}
+

patterns/design-patterns-structural/src/test/java/com/baeldung/bridge/BridgePatternIntegrationTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.bridge;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class BridgePatternIntegrationTest {
+	
+    @Test
+    public void whenBridgePatternInvoked_thenConfigSuccess() {
+        //a square with red color
+        Shape square = new Square(new Red());
+        assertEquals(square.draw(), "Square drawn. Color is Red");
+        
+        //a triangle with blue color
+        Shape triangle = new Triangle(new Blue());
+        assertEquals(triangle.draw(), "Triangle drawn. Color is Blue");
+    }
+}
+

patterns/design-patterns-structural/src/test/java/com/baeldung/decorator/DecoratorPatternIntegrationTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.decorator;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class DecoratorPatternIntegrationTest {
+    @Test
+    public void givenDecoratorPattern_WhenDecoratorsInjectedAtRuntime_thenConfigSuccess() {
+        ChristmasTree tree1 = new Garland(new ChristmasTreeImpl());
+        assertEquals(tree1.decorate(), 
+          "Christmas tree with Garland");
+         
+        ChristmasTree tree2 = new BubbleLights(
+          new Garland(new Garland(new ChristmasTreeImpl())));
+        assertEquals(tree2.decorate(), 
+          "Christmas tree with Garland with Garland with Bubble Lights");
+    }
+}
+

patterns/design-patterns-structural/src/test/java/com/baeldung/facade/CarEngineFacadeIntegrationTest.java

@@ -0,0 +1,85 @@
+package com.baeldung.facade;
+
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.AppenderBase;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class CarEngineFacadeIntegrationTest {
+
+
+    private InMemoryCustomTestAppender appender;
+
+
+    @Before
+    public void setUp() {
+        appender = new InMemoryCustomTestAppender();
+    }
+
+    @After
+    public void tearDown() {
+        appender.stop();
+    }
+
+
+    @Test
+    public void whenStartEngine_thenAllNecessaryActionsPerformed() {
+        CarEngineFacade carEngineFacade = new CarEngineFacade();
+        carEngineFacade.startEngine();
+        assertTrue(appender.logContains("Fuel injector ready to inject fuel."));
+        assertTrue(appender.logContains("Getting air measurements.."));
+        assertTrue(appender.logContains("Air provided!"));
+        assertTrue(appender.logContains("Fuel injector ready to inject fuel."));
+        assertTrue(appender.logContains("Fuel Pump is pumping fuel.."));
+        assertTrue(appender.logContains("Fuel injected."));
+        assertTrue(appender.logContains("Starting.."));
+        assertTrue(appender.logContains("Setting temperature upper limit to 90"));
+        assertTrue(appender.logContains("Cooling Controller ready!"));
+        assertTrue(appender.logContains("Setting radiator speed to 10"));
+        assertTrue(appender.logContains("Catalytic Converter switched on!"));
+    }
+
+
+    @Test
+    public void whenStopEngine_thenAllNecessaryActionsPerformed() {
+        CarEngineFacade carEngineFacade = new CarEngineFacade();
+        carEngineFacade.stopEngine();
+        assertTrue(appender.logContains("Stopping Fuel injector.."));
+        assertTrue(appender.logContains("Catalytic Converter switched off!"));
+        assertTrue(appender.logContains("Scheduled cooling with maximum allowed temperature 50"));
+        assertTrue(appender.logContains("Getting temperature from the sensor.."));
+        assertTrue(appender.logContains("Radiator switched on!"));
+        assertTrue(appender.logContains("Stopping Cooling Controller.."));
+        assertTrue(appender.logContains("Radiator switched off!"));
+        assertTrue(appender.logContains("Air controller switched off."));
+    }
+
+    private class InMemoryCustomTestAppender extends AppenderBase<ILoggingEvent> {
+
+        private List<ILoggingEvent> logs = new ArrayList<>();
+
+        public InMemoryCustomTestAppender() {
+            ((Logger) LoggerFactory.getLogger("root")).addAppender(this);
+            start();
+        }
+
+        @Override
+        protected void append(ILoggingEvent eventObject) {
+            logs.add(eventObject);
+        }
+
+        public boolean logContains(String message) {
+            return logs.stream().anyMatch(event -> event.getFormattedMessage().equals(message));
+        }
+    }
+
+
+}

patterns/design-patterns-structural/src/test/java/com/baeldung/proxy/ProxyPatternIntegrationTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.proxy;
+
+import static com.baeldung.util.LoggerUtil.LOG;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+
+import java.util.List;
+
+import org.apache.log4j.spi.LoggingEvent;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ProxyPatternIntegrationTest {
+    public static TestAppenderDP appender;
+    
+    @Before
+    public void setUp() {
+        appender = new TestAppenderDP();
+        LOG.addAppender(appender);
+    }
+    
+    @Test
+    public void givenExpensiveObjectProxy_WhenObjectInitialized_thenInitializedOnlyOnce() {
+        ExpensiveObject object = new ExpensiveObjectProxy();
+        object.process();
+        object.process();
+
+        final List<LoggingEvent> log = appender.getLog();
+        
+        assertThat((String) log.get(0).getMessage(), is("Loading initial configuration.."));
+        assertThat((String) log.get(1).getMessage(), is("processing complete."));
+        assertThat((String) log.get(2).getMessage(), is("processing complete."));
+    }
+    
+    @After
+    public void tearDown() {
+        LOG.removeAppender(appender);
+    }
+}
+

patterns/design-patterns-structural/src/test/java/com/baeldung/proxy/TestAppenderDP.java

@@ -0,0 +1,29 @@
+package com.baeldung.proxy;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.log4j.AppenderSkeleton;
+import org.apache.log4j.spi.LoggingEvent;
+
+public class TestAppenderDP extends AppenderSkeleton {
+    private final List<LoggingEvent> log = new ArrayList<LoggingEvent>();
+
+    @Override
+    public boolean requiresLayout() {
+        return false;
+    }
+
+    @Override
+    protected void append(final LoggingEvent loggingEvent) {
+        log.add(loggingEvent);
+    }
+
+    @Override
+    public void close() {
+    }
+
+    public List<LoggingEvent> getLog() {
+        return new ArrayList<LoggingEvent>(log);
+    }
+}