Java设计模式

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/AdapterPatternDemo.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+/**
+ * 适配器模式（Adapter Pattern）
+ */
+public class AdapterPatternDemo {
+
+    public static void main(String[] args) {
+        AudioPlayer audioPlayer = new AudioPlayer();
+
+        audioPlayer.play("mp3", "beyond the horizon.mp3");
+        audioPlayer.play("mp4", "alone.mp4");
+        audioPlayer.play("vlc", "far far away.vlc");
+        audioPlayer.play("avi", "mind me.avi");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/AdvancedMediaPlayer.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public interface AdvancedMediaPlayer {
+
+    public void playVlc(String fileName);
+
+    public void playMp4(String fileName);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/AudioPlayer.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public class AudioPlayer implements MediaPlayer {
+
+    MediaAdapter mediaAdapter;
+
+    @Override
+    public void play(String audioType, String fileName) {
+
+        //播放 mp3 音乐文件的内置支持
+        if (audioType.equalsIgnoreCase("mp3")) {
+            System.out.println("Playing mp3 file. Name: "+ fileName);
+        }
+        //mediaAdapter 提供了播放其他文件格式的支持
+        else if (audioType.equalsIgnoreCase("vlc")
+                || audioType.equalsIgnoreCase("mp4")) {
+            mediaAdapter = new MediaAdapter(audioType);
+            mediaAdapter.play(audioType, fileName);
+        } else {
+            System.out.println("Invalid media. " + audioType + " format not supported");
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/MediaAdapter.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public class MediaAdapter implements MediaPlayer {
+
+    AdvancedMediaPlayer advancedMusicPlayer;
+
+    public MediaAdapter(String audioType) {
+        if (audioType.equalsIgnoreCase("vlc") ) {
+            advancedMusicPlayer = new VlcPlayer();
+        } else if (audioType.equalsIgnoreCase("mp4")) {
+            advancedMusicPlayer = new Mp4Player();
+        }
+    }
+
+    @Override
+    public void play(String audioType, String fileName) {
+        if (audioType.equalsIgnoreCase("vlc")) {
+            advancedMusicPlayer.playVlc(fileName);
+        } else if (audioType.equalsIgnoreCase("mp4")) {
+            advancedMusicPlayer.playMp4(fileName);
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/MediaPlayer.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public interface MediaPlayer {
+
+    public void play(String audioType, String fileName);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/Mp4Player.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public class Mp4Player implements AdvancedMediaPlayer {
+
+    @Override
+    public void playVlc(String fileName) {
+        //什么也不做
+    }
+
+    @Override
+    public void playMp4(String fileName) {
+        System.out.println("Playing mp4 file. Name: "+ fileName);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/adapter/VlcPlayer.java

+package cn.datax.learning.design.patterns.structural.adapter;
+
+public class VlcPlayer implements AdvancedMediaPlayer {
+
+    @Override
+    public void playVlc(String fileName) {
+        System.out.println("Playing vlc file. Name: "+ fileName);
+    }
+
+    @Override
+    public void playMp4(String fileName) {
+        //什么也不做
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/BridgePatternDemo.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+/**
+ * 桥接模式（Bridge Pattern）
+ */
+public class BridgePatternDemo {
+
+    public static void main(String[] args) {
+        Shape redCircle = new Circle(100, 100, 10, new RedCircle());
+        Shape greenCircle = new Circle(100, 100, 10, new GreenCircle());
+
+        redCircle.draw();
+        greenCircle.draw();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/Circle.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+public class Circle extends Shape {
+
+    private int x, y, radius;
+
+    public Circle(int x, int y, int radius, DrawApi drawApi) {
+        super(drawApi);
+        this.x = x;
+        this.y = y;
+        this.radius = radius;
+    }
+
+    @Override
+    public void draw() {
+        drawApi.drawCircle(radius, x, y);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/DrawApi.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+public interface DrawApi {
+
+    public void drawCircle(int radius, int x, int y);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/GreenCircle.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+public class GreenCircle implements DrawApi {
+
+    @Override
+    public void drawCircle(int radius, int x, int y) {
+        System.out.println("Drawing Circle[ color: green, radius: "
+                + radius + ", x: " + x + ", " + y + "]");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/RedCircle.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+public class RedCircle implements DrawApi {
+
+    @Override
+    public void drawCircle(int radius, int x, int y) {
+        System.out.println("Drawing Circle[ color: red, radius: "
+                + radius + ", x: " + x + ", " + y + "]");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/bridge/Shape.java

+package cn.datax.learning.design.patterns.structural.bridge;
+
+public abstract class Shape {
+
+    protected DrawApi drawApi;
+
+    protected Shape(DrawApi drawApi) {
+        this.drawApi = drawApi;
+    }
+
+    public abstract void draw();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/composite/CompositePatternDemo.java

+package cn.datax.learning.design.patterns.structural.composite;
+
+/**
+ * 组合模式（Composite Pattern）
+ */
+public class CompositePatternDemo {
+
+    public static void main(String[] args) {
+        Employee CEO = new Employee("John", "CEO", 30000);
+
+        Employee headSales = new Employee("Robert", "Head Sales", 20000);
+
+        Employee headMarketing = new Employee("Michel", "Head Marketing", 20000);
+
+        Employee clerk1 = new Employee("Laura", "Marketing", 10000);
+        Employee clerk2 = new Employee("Bob", "Marketing", 10000);
+
+        Employee salesExecutive1 = new Employee("Richard", "Sales", 10000);
+        Employee salesExecutive2 = new Employee("Rob", "Sales", 10000);
+
+        CEO.add(headSales);
+        CEO.add(headMarketing);
+
+        headSales.add(salesExecutive1);
+        headSales.add(salesExecutive2);
+
+        headMarketing.add(clerk1);
+        headMarketing.add(clerk2);
+
+        //打印该组织的所有员工
+        System.out.println(CEO);
+        for (Employee headEmployee : CEO.getSubordinates()) {
+            System.out.println(headEmployee);
+            for (Employee employee : headEmployee.getSubordinates()) {
+                System.out.println(employee);
+            }
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/composite/Employee.java

+package cn.datax.learning.design.patterns.structural.composite;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Employee {
+
+    private String name;
+    private String dept;
+    private int salary;
+    private List<Employee> subordinates;
+
+    //构造函数
+    public Employee(String name,String dept, int sal) {
+        this.name = name;
+        this.dept = dept;
+        this.salary = sal;
+        subordinates = new ArrayList<Employee>();
+    }
+
+    public void add(Employee e) {
+        subordinates.add(e);
+    }
+
+    public void remove(Employee e) {
+        subordinates.remove(e);
+    }
+
+    public List<Employee> getSubordinates() {
+        return subordinates;
+    }
+
+    public String toString() {
+        return ("Employee :[ Name : "+ name
+                +", dept : "+ dept + ", salary :"
+                + salary+" ]");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/AndCriteria.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.List;
+
+public class AndCriteria implements Criteria {
+
+    private Criteria criteria;
+    private Criteria otherCriteria;
+
+    public AndCriteria(Criteria criteria, Criteria otherCriteria) {
+        this.criteria = criteria;
+        this.otherCriteria = otherCriteria;
+    }
+
+    @Override
+    public List<Person> meetCriteria(List<Person> persons) {
+        List<Person> firstCriteriaPersons = criteria.meetCriteria(persons);
+        return otherCriteria.meetCriteria(firstCriteriaPersons);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/Criteria.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.List;
+
+public interface Criteria {
+
+    public List<Person> meetCriteria(List<Person> persons);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/CriteriaFemale.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CriteriaFemale implements Criteria {
+
+    @Override
+    public List<Person> meetCriteria(List<Person> persons) {
+        List<Person> femalePersons = new ArrayList<Person>();
+        for (Person person : persons) {
+            if (person.getGender().equalsIgnoreCase("FEMALE")) {
+                femalePersons.add(person);
+            }
+        }
+        return femalePersons;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/CriteriaMale.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CriteriaMale implements Criteria {
+
+    @Override
+    public List<Person> meetCriteria(List<Person> persons) {
+        List<Person> malePersons = new ArrayList<Person>();
+        for (Person person : persons) {
+            if (person.getGender().equalsIgnoreCase("MALE")) {
+                malePersons.add(person);
+            }
+        }
+        return malePersons;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/CriteriaPatternDemo.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 过滤器模式（Filter、Criteria Pattern）
+ */
+public class CriteriaPatternDemo {
+
+    public static void main(String[] args) {
+        List<Person> persons = new ArrayList<Person>();
+
+        persons.add(new Person("Robert","Male", "Single"));
+        persons.add(new Person("John","Male", "Married"));
+        persons.add(new Person("Laura","Female", "Married"));
+        persons.add(new Person("Diana","Female", "Single"));
+        persons.add(new Person("Mike","Male", "Single"));
+        persons.add(new Person("Bobby","Male", "Single"));
+
+        Criteria male = new CriteriaMale();
+        Criteria female = new CriteriaFemale();
+        Criteria single = new CriteriaSingle();
+        Criteria singleMale = new AndCriteria(single, male);
+        Criteria singleOrFemale = new OrCriteria(single, female);
+
+        System.out.println("Males: ");
+        printPersons(male.meetCriteria(persons));
+
+        System.out.println("\nFemales: ");
+        printPersons(female.meetCriteria(persons));
+
+        System.out.println("\nSingle Males: ");
+        printPersons(singleMale.meetCriteria(persons));
+
+        System.out.println("\nSingle Or Females: ");
+        printPersons(singleOrFemale.meetCriteria(persons));
+    }
+
+    public static void printPersons(List<Person> persons){
+        for (Person person : persons) {
+            System.out.println("Person : [ Name : " + person.getName()
+                    +", Gender : " + person.getGender()
+                    +", Marital Status : " + person.getMaritalStatus()
+                    +" ]");
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/CriteriaSingle.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CriteriaSingle implements Criteria {
+
+    @Override
+    public List<Person> meetCriteria(List<Person> persons) {
+        List<Person> singlePersons = new ArrayList<Person>();
+        for (Person person : persons) {
+            if (person.getMaritalStatus().equalsIgnoreCase("SINGLE")) {
+                singlePersons.add(person);
+            }
+        }
+        return singlePersons;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/OrCriteria.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+import java.util.List;
+
+public class OrCriteria implements Criteria {
+
+    private Criteria criteria;
+    private Criteria otherCriteria;
+
+    public OrCriteria(Criteria criteria, Criteria otherCriteria) {
+        this.criteria = criteria;
+        this.otherCriteria = otherCriteria;
+    }
+
+    @Override
+    public List<Person> meetCriteria(List<Person> persons) {
+        List<Person> firstCriteriaItems = criteria.meetCriteria(persons);
+        List<Person> otherCriteriaItems = otherCriteria.meetCriteria(persons);
+
+        for (Person person : otherCriteriaItems) {
+            if (!firstCriteriaItems.contains(person)) {
+                firstCriteriaItems.add(person);
+            }
+        }
+        return firstCriteriaItems;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/criteria/Person.java

+package cn.datax.learning.design.patterns.structural.criteria;
+
+public class Person {
+
+    private String name;
+
+    private String gender;
+
+    private String maritalStatus;
+
+    public Person(String name,String gender,String maritalStatus) {
+        this.name = name;
+        this.gender = gender;
+        this.maritalStatus = maritalStatus;
+    }
+
+    public String getName() {
+        return name;
+    }
+    public String getGender() {
+        return gender;
+    }
+    public String getMaritalStatus() {
+        return maritalStatus;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/Circle.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+public class Circle implements Shape {
+
+    @Override
+    public void draw() {
+        System.out.println("Shape: Circle");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/DecoratorPatternDemo.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+/**
+ * 装饰器模式（Decorator Pattern）
+ */
+public class DecoratorPatternDemo {
+
+    public static void main(String[] args) {
+        Shape circle = new Circle();
+        ShapeDecorator redCircle = new RedShapeDecorator(new Circle());
+        ShapeDecorator redRectangle = new RedShapeDecorator(new Rectangle());
+
+        System.out.println("Circle with normal border");
+        circle.draw();
+
+        System.out.println("\nCircle of red border");
+        redCircle.draw();
+
+        System.out.println("\nRectangle of red border");
+        redRectangle.draw();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/Rectangle.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+public class Rectangle implements Shape {
+
+    @Override
+    public void draw() {
+        System.out.println("Shape: Rectangle");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/RedShapeDecorator.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+public class RedShapeDecorator extends ShapeDecorator {
+
+    public RedShapeDecorator(Shape decoratedShape) {
+        super(decoratedShape);
+    }
+
+    @Override
+    public void draw() {
+        decoratedShape.draw();
+        setRedBorder(decoratedShape);
+    }
+
+    private void setRedBorder(Shape decoratedShape) {
+        System.out.println("Border Color: Red");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/Shape.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+public interface Shape {
+
+    void draw();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/decorator/ShapeDecorator.java

+package cn.datax.learning.design.patterns.structural.decorator;
+
+public abstract class ShapeDecorator implements Shape {
+
+    protected Shape decoratedShape;
+
+    public ShapeDecorator(Shape decoratedShape) {
+        this.decoratedShape = decoratedShape;
+    }
+
+    public void draw() {
+        decoratedShape.draw();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/Circle.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+public class Circle implements Shape {
+
+    @Override
+    public void draw() {
+        System.out.println("Circle::draw()");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/FacadePatternDemo.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+/**
+ * 外观模式（Facade Pattern）
+ */
+public class FacadePatternDemo {
+
+    public static void main(String[] args) {
+        ShapeMaker shapeMaker = new ShapeMaker();
+
+        shapeMaker.drawCircle();
+        shapeMaker.drawRectangle();
+        shapeMaker.drawSquare();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/Rectangle.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+public class Rectangle implements Shape {
+
+    @Override
+    public void draw() {
+        System.out.println("Rectangle::draw()");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/Shape.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+public interface Shape {
+
+    void draw();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/ShapeMaker.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+public class ShapeMaker {
+
+    private Shape circle;
+
+    private Shape rectangle;
+
+    private Shape square;
+
+    public ShapeMaker() {
+        circle = new Circle();
+        rectangle = new Rectangle();
+        square = new Square();
+    }
+
+    public void drawCircle() {
+        circle.draw();
+    }
+    public void drawRectangle() {
+        rectangle.draw();
+    }
+    public void drawSquare() {
+        square.draw();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/facade/Square.java

+package cn.datax.learning.design.patterns.structural.facade;
+
+public class Square implements Shape {
+
+    @Override
+    public void draw() {
+        System.out.println("Square::draw()");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/flyweight/Circle.java

+package cn.datax.learning.design.patterns.structural.flyweight;
+
+public class Circle implements Shape {
+
+    private String color;
+
+    private int x;
+
+    private int y;
+
+    private int radius;
+
+    public Circle(String color) {
+        this.color = color;
+    }
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public void setY(int y) {
+        this.y = y;
+    }
+
+    public void setRadius(int radius) {
+        this.radius = radius;
+    }
+
+    @Override
+    public void draw() {
+        System.out.println("Circle: Draw() [Color : " + color
+                + ", x : " + x + ", y :" + y + ", radius :" + radius);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/flyweight/FlyweightPatternDemo.java

+package cn.datax.learning.design.patterns.structural.flyweight;
+
+/**
+ * 享元模式（Flyweight Pattern）
+ */
+public class FlyweightPatternDemo {
+
+    private static final String colors[] = { "Red", "Green", "Blue", "White", "Black" };
+    public static void main(String[] args) {
+        for(int i=0; i < 20; ++i) {
+            Circle circle = (Circle)ShapeFactory.getCircle(getRandomColor());
+            circle.setX(getRandomX());
+            circle.setY(getRandomY());
+            circle.setRadius(100);
+            circle.draw();
+        }
+    }
+
+    private static String getRandomColor() {
+        return colors[(int)(Math.random()*colors.length)];
+    }
+
+    private static int getRandomX() {
+        return (int)(Math.random()*100);
+    }
+
+    private static int getRandomY() {
+        return (int)(Math.random()*100);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/flyweight/Shape.java

+package cn.datax.learning.design.patterns.structural.flyweight;
+
+public interface Shape {
+
+    void draw();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/flyweight/ShapeFactory.java

+package cn.datax.learning.design.patterns.structural.flyweight;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class ShapeFactory {
+
+    private static final ConcurrentHashMap<String, Shape> circleMap = new ConcurrentHashMap<>();
+
+    public static Shape getCircle(String color) {
+        Circle circle = (Circle)circleMap.get(color);
+
+        if(circle == null) {
+            circle = new Circle(color);
+            circleMap.put(color, circle);
+            System.out.println("Creating circle of color : " + color);
+        }
+        return circle;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/proxy/Image.java

+package cn.datax.learning.design.patterns.structural.proxy;
+
+public interface Image {
+
+    void display();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/proxy/ProxyImage.java

+package cn.datax.learning.design.patterns.structural.proxy;
+
+public class ProxyImage implements Image {
+
+    private RealImage realImage;
+    private String fileName;
+
+    public ProxyImage(String fileName) {
+        this.fileName = fileName;
+    }
+
+    @Override
+    public void display() {
+        if (realImage == null) {
+            realImage = new RealImage(fileName);
+        }
+        realImage.display();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/proxy/ProxyPatternDemo.java

+package cn.datax.learning.design.patterns.structural.proxy;
+
+/**
+ * 代理模式（Proxy Pattern）
+ */
+public class ProxyPatternDemo {
+
+    public static void main(String[] args) {
+        Image image = new ProxyImage("test_10mb.jpg");
+
+        // 图像将从磁盘加载
+        image.display();
+        // 图像不需要从磁盘加载
+        image.display();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/structural/proxy/RealImage.java

+package cn.datax.learning.design.patterns.structural.proxy;
+
+public class RealImage implements Image {
+
+    private String fileName;
+
+    public RealImage(String fileName) {
+        this.fileName = fileName;
+        loadFromDisk(fileName);
+    }
+
+    @Override
+    public void display() {
+        System.out.println("Displaying " + fileName);
+    }
+
+    private void loadFromDisk(String fileName) {
+        System.out.println("Loading " + fileName);
+    }
+}