java设计模式

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/chain/AbstractLogger.java

+package cn.datax.learning.design.patterns.behavioral.chain;
+
+public abstract class AbstractLogger {
+
+    public static int INFO = 1;
+
+    public static int DEBUG = 2;
+
+    public static int ERROR = 3;
+
+    protected int level;
+
+    //责任链中的下一个元素
+    protected AbstractLogger nextLogger;
+
+    public void setNextLogger(AbstractLogger nextLogger) {
+        this.nextLogger = nextLogger;
+    }
+
+    public void logMessage(int level, String message) {
+        if (this.level <= level) {
+            write(message);
+        }
+        if (nextLogger !=null) {
+            nextLogger.logMessage(level, message);
+        }
+    }
+
+    abstract protected void write(String message);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/chain/ChainPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.chain;
+
+/**
+ * 责任链模式（Chain of Responsibility Pattern）
+ */
+public class ChainPatternDemo {
+
+    private static AbstractLogger getChainOfLoggers(){
+        AbstractLogger errorLogger = new ErrorLogger(AbstractLogger.ERROR);
+        AbstractLogger fileLogger = new FileLogger(AbstractLogger.DEBUG);
+        AbstractLogger consoleLogger = new ConsoleLogger(AbstractLogger.INFO);
+
+        errorLogger.setNextLogger(fileLogger);
+        fileLogger.setNextLogger(consoleLogger);
+
+        return errorLogger;
+    }
+
+    public static void main(String[] args) {
+        AbstractLogger loggerChain = getChainOfLoggers();
+
+        loggerChain.logMessage(AbstractLogger.INFO, "This is an information.");
+
+        loggerChain.logMessage(AbstractLogger.DEBUG, "This is a debug level information.");
+
+        loggerChain.logMessage(AbstractLogger.ERROR, "This is an error information.");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/chain/ConsoleLogger.java

+package cn.datax.learning.design.patterns.behavioral.chain;
+
+public class ConsoleLogger extends AbstractLogger {
+
+    public ConsoleLogger(int level) {
+        this.level = level;
+    }
+
+    @Override
+    protected void write(String message) {
+        System.out.println("Standard Console::Logger: " + message);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/chain/ErrorLogger.java

+package cn.datax.learning.design.patterns.behavioral.chain;
+
+public class ErrorLogger extends AbstractLogger {
+
+    public ErrorLogger(int level) {
+        this.level = level;
+    }
+
+    @Override
+    protected void write(String message) {
+        System.out.println("Error Console::Logger: " + message);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/chain/FileLogger.java

+package cn.datax.learning.design.patterns.behavioral.chain;
+
+public class FileLogger extends AbstractLogger {
+
+    public FileLogger(int level) {
+        this.level = level;
+    }
+
+    @Override
+    protected void write(String message) {
+        System.out.println("File::Logger: " + message);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/Broker.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Broker {
+
+    private List<Order> orderList = new ArrayList<Order>();
+
+    public void takeOrder(Order order) {
+        orderList.add(order);
+    }
+
+    public void placeOrders() {
+        for (Order order : orderList) {
+            order.execute();
+        }
+        orderList.clear();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/BuyStock.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+public class BuyStock implements Order {
+
+    private Stock abcStock;
+
+    public BuyStock(Stock abcStock) {
+        this.abcStock = abcStock;
+    }
+
+    public void execute() {
+        abcStock.buy();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/CommandPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+/**
+ * 命令模式（Command Pattern）
+ */
+public class CommandPatternDemo {
+
+    public static void main(String[] args) {
+        Stock abcStock = new Stock();
+
+        BuyStock buyStockOrder = new BuyStock(abcStock);
+        SellStock sellStockOrder = new SellStock(abcStock);
+
+        Broker broker = new Broker();
+        broker.takeOrder(buyStockOrder);
+        broker.takeOrder(sellStockOrder);
+
+        broker.placeOrders();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/Order.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+public interface Order {
+
+    void execute();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/SellStock.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+public class SellStock implements Order {
+
+    private Stock abcStock;
+
+    public SellStock(Stock abcStock) {
+        this.abcStock = abcStock;
+    }
+
+    public void execute() {
+        abcStock.sell();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/command/Stock.java

+package cn.datax.learning.design.patterns.behavioral.command;
+
+public class Stock {
+
+    private String name = "ABC";
+
+    private int quantity = 10;
+
+    public void buy() {
+        System.out.println("Stock [ Name: " + name + ", Quantity: " + quantity + " ] bought");
+    }
+
+    public void sell() {
+        System.out.println("Stock [ Name: " + name + ", Quantity: " + quantity + " ] sold");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/interpreter/AndExpression.java

+package cn.datax.learning.design.patterns.behavioral.interpreter;
+
+public class AndExpression implements Expression {
+
+    private Expression expr1 = null;
+    private Expression expr2 = null;
+
+    public AndExpression(Expression expr1, Expression expr2) {
+        this.expr1 = expr1;
+        this.expr2 = expr2;
+    }
+
+    @Override
+    public boolean interpret(String context) {
+        return expr1.interpret(context) && expr2.interpret(context);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/interpreter/Expression.java

+package cn.datax.learning.design.patterns.behavioral.interpreter;
+
+public interface Expression {
+
+    public boolean interpret(String context);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/interpreter/InterpreterPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.interpreter;
+
+/**
+ * 解释器模式（Interpreter Pattern）
+ */
+public class InterpreterPatternDemo {
+
+    //规则：Robert 和 John 是男性
+    public static Expression getMaleExpression() {
+        Expression robert = new TerminalExpression("Robert");
+        Expression john = new TerminalExpression("John");
+        return new OrExpression(robert, john);
+    }
+
+    //规则：Julie 是一个已婚的女性
+    public static Expression getMarriedWomanExpression() {
+        Expression julie = new TerminalExpression("Julie");
+        Expression married = new TerminalExpression("Married");
+        return new AndExpression(julie, married);
+    }
+
+    public static void main(String[] args) {
+        Expression isMale = getMaleExpression();
+        Expression isMarriedWoman = getMarriedWomanExpression();
+
+        System.out.println("John is male? " + isMale.interpret("John"));
+        System.out.println("Julie is a married women? " + isMarriedWoman.interpret("Married Julie"));
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/interpreter/OrExpression.java

+package cn.datax.learning.design.patterns.behavioral.interpreter;
+
+public class OrExpression implements Expression {
+
+    private Expression expr1 = null;
+    private Expression expr2 = null;
+
+    public OrExpression(Expression expr1, Expression expr2) {
+        this.expr1 = expr1;
+        this.expr2 = expr2;
+    }
+
+    @Override
+    public boolean interpret(String context) {
+        return expr1.interpret(context) || expr2.interpret(context);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/interpreter/TerminalExpression.java

+package cn.datax.learning.design.patterns.behavioral.interpreter;
+
+public class TerminalExpression implements Expression {
+
+    private String data;
+
+    public TerminalExpression(String data) {
+        this.data = data;
+    }
+
+    @Override
+    public boolean interpret(String context) {
+        if (context.contains(data)) {
+            return true;
+        }
+        return false;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/iterator/Container.java

+package cn.datax.learning.design.patterns.behavioral.iterator;
+
+public interface Container {
+
+    public Iterator getIterator();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/iterator/Iterator.java

+package cn.datax.learning.design.patterns.behavioral.iterator;
+
+public interface Iterator {
+
+    public boolean hasNext();
+
+    public Object next();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/iterator/IteratorPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.iterator;
+
+/**
+ * 迭代器模式（Iterator Pattern）
+ */
+public class IteratorPatternDemo {
+
+    public static void main(String[] args) {
+        NameRepository namesRepository = new NameRepository();
+
+        for (Iterator iter = namesRepository.getIterator(); iter.hasNext();) {
+            String name = (String)iter.next();
+            System.out.println("Name : " + name);
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/iterator/NameRepository.java

+package cn.datax.learning.design.patterns.behavioral.iterator;
+
+public class NameRepository implements Container {
+
+    public String names[] = {"Robert" , "John" ,"Julie" , "Lora"};
+
+    @Override
+    public Iterator getIterator() {
+        return new StringArrayIterator(names);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/iterator/StringArrayIterator.java

+package cn.datax.learning.design.patterns.behavioral.iterator;
+
+public class StringArrayIterator implements Iterator{
+
+    String[] args;
+
+    int index = 0;
+
+    public StringArrayIterator(String[] argsTemp) {
+        this.args  = argsTemp;
+    }
+
+    @Override
+    public boolean hasNext(){
+        if(index < args.length){
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public Object next(){
+        if(index < args.length){
+            return args[index++];
+        }
+        return null;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/mediator/ChatRoom.java

+package cn.datax.learning.design.patterns.behavioral.mediator;
+
+import java.util.Date;
+
+public class ChatRoom {
+
+    public static void showMessage(User user, String message) {
+        System.out.println(new Date().toString()
+                + " [" + user.getName() + "] : " + message);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/mediator/MediatorPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.mediator;
+
+/**
+ * 中介者模式（Mediator Pattern）
+ */
+public class MediatorPatternDemo {
+
+    public static void main(String[] args) {
+        User robert = new User("Robert");
+        User john = new User("John");
+
+        robert.sendMessage("Hi! John!");
+        john.sendMessage("Hello! Robert!");
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/mediator/User.java

+package cn.datax.learning.design.patterns.behavioral.mediator;
+
+public class User {
+
+    private String name;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public User(String name) {
+        this.name  = name;
+    }
+
+    public void sendMessage(String message) {
+        ChatRoom.showMessage(this, message);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/memento/CareTaker.java

+package cn.datax.learning.design.patterns.behavioral.memento;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CareTaker {
+
+    private List<Memento> mementoList = new ArrayList<Memento>();
+
+    public void add(Memento state) {
+        mementoList.add(state);
+    }
+
+    public Memento get(int index) {
+        return mementoList.get(index);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/memento/Memento.java

+package cn.datax.learning.design.patterns.behavioral.memento;
+
+public class Memento {
+
+    private String state;
+
+    public Memento(String state) {
+        this.state = state;
+    }
+
+    public String getState() {
+        return state;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/memento/MementoPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.memento;
+
+/**
+ * 备忘录模式（Memento Pattern）
+ */
+public class MementoPatternDemo {
+
+    public static void main(String[] args) {
+        Originator originator = new Originator();
+        CareTaker careTaker = new CareTaker();
+        originator.setState("State #1");
+        originator.setState("State #2");
+        careTaker.add(originator.saveStateToMemento());
+        originator.setState("State #3");
+        careTaker.add(originator.saveStateToMemento());
+        originator.setState("State #4");
+
+        System.out.println("Current State: " + originator.getState());
+        originator.getStateFromMemento(careTaker.get(0));
+        System.out.println("First saved State: " + originator.getState());
+        originator.getStateFromMemento(careTaker.get(1));
+        System.out.println("Second saved State: " + originator.getState());
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/memento/Originator.java

+package cn.datax.learning.design.patterns.behavioral.memento;
+
+public class Originator {
+
+    private String state;
+
+    public void setState(String state) {
+        this.state = state;
+    }
+
+    public String getState() {
+        return state;
+    }
+
+    public Memento saveStateToMemento() {
+        return new Memento(state);
+    }
+
+    public void getStateFromMemento(Memento Memento) {
+        state = Memento.getState();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/nullPattern/AbstractCustomer.java

+package cn.datax.learning.design.patterns.behavioral.nullPattern;
+
+public abstract class AbstractCustomer {
+
+    protected String name;
+
+    public abstract boolean isNil();
+
+    public abstract String getName();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/nullPattern/CustomerFactory.java

+package cn.datax.learning.design.patterns.behavioral.nullPattern;
+
+public class CustomerFactory {
+
+    public static final String[] names = {"Rob", "Joe", "Julie"};
+
+    public static AbstractCustomer getCustomer(String name) {
+        for (int i = 0; i < names.length; i++) {
+            if (names[i].equalsIgnoreCase(name)) {
+                return new RealCustomer(name);
+            }
+        }
+        return new NullCustomer();
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/nullPattern/NullCustomer.java

+package cn.datax.learning.design.patterns.behavioral.nullPattern;
+
+public class NullCustomer extends AbstractCustomer {
+
+    @Override
+    public String getName() {
+        return "Not Available in Customer Database";
+    }
+
+    @Override
+    public boolean isNil() {
+        return true;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/nullPattern/NullPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.nullPattern;
+
+/**
+ * 空对象模式（Null Object Pattern）
+ */
+public class NullPatternDemo {
+
+    public static void main(String[] args) {
+        AbstractCustomer customer1 = CustomerFactory.getCustomer("Rob");
+        AbstractCustomer customer2 = CustomerFactory.getCustomer("Bob");
+        AbstractCustomer customer3 = CustomerFactory.getCustomer("Julie");
+        AbstractCustomer customer4 = CustomerFactory.getCustomer("Laura");
+
+        System.out.println("Customers");
+        System.out.println(customer1.getName());
+        System.out.println(customer2.getName());
+        System.out.println(customer3.getName());
+        System.out.println(customer4.getName());
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/nullPattern/RealCustomer.java

+package cn.datax.learning.design.patterns.behavioral.nullPattern;
+
+public class RealCustomer extends AbstractCustomer {
+
+    public RealCustomer(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public boolean isNil() {
+        return false;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/BinaryObserver.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+public class BinaryObserver extends Observer{
+
+    public BinaryObserver(Subject subject) {
+        this.subject = subject;
+        this.subject.attach(this);
+    }
+
+    @Override
+    public void update() {
+        System.out.println( "Binary String: "
+                + Integer.toBinaryString( subject.getState()));
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/HexaObserver.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+public class HexaObserver extends Observer{
+
+    public HexaObserver(Subject subject) {
+        this.subject = subject;
+        this.subject.attach(this);
+    }
+
+    @Override
+    public void update() {
+        System.out.println( "Hex String: "
+                + Integer.toHexString( subject.getState()).toUpperCase());
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/Observer.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+public abstract class Observer {
+
+    protected Subject subject;
+
+    public abstract void update();
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/ObserverPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+/**
+ * 观察者模式（Observer Pattern）
+ */
+public class ObserverPatternDemo {
+
+    public static void main(String[] args) {
+        Subject subject = new Subject();
+
+        new HexaObserver(subject);
+        new OctalObserver(subject);
+        new BinaryObserver(subject);
+
+        System.out.println("First state change: 15");
+        subject.setState(15);
+        System.out.println("Second state change: 10");
+        subject.setState(10);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/OctalObserver.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+public class OctalObserver extends Observer{
+
+    public OctalObserver(Subject subject) {
+        this.subject = subject;
+        this.subject.attach(this);
+    }
+
+    @Override
+    public void update() {
+        System.out.println( "Octal String: "
+                + Integer.toOctalString( subject.getState()));
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/observer/Subject.java

+package cn.datax.learning.design.patterns.behavioral.observer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Subject {
+
+    private List<Observer> observers = new ArrayList<Observer>();
+
+    private int state;
+
+    public int getState() {
+        return state;
+    }
+
+    public void setState(int state) {
+        this.state = state;
+        notifyAllObservers();
+    }
+
+    public void attach(Observer observer) {
+        observers.add(observer);
+    }
+
+    public void notifyAllObservers() {
+        for (Observer observer : observers) {
+            observer.update();
+        }
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/state/Context.java

+package cn.datax.learning.design.patterns.behavioral.state;
+
+public class Context {
+
+    private State state;
+
+    public Context(){
+        state = null;
+    }
+
+    public void setState(State state) {
+        this.state = state;
+    }
+
+    public State getState() {
+        return state;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/state/StartState.java

+package cn.datax.learning.design.patterns.behavioral.state;
+
+public class StartState implements State {
+
+    public void doAction(Context context) {
+        System.out.println("Player is in start state");
+        context.setState(this);
+    }
+
+    public String toString() {
+        return "Start State";
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/state/State.java

+package cn.datax.learning.design.patterns.behavioral.state;
+
+public interface State {
+
+    public void doAction(Context context);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/state/StatePatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.state;
+
+/**
+ * 状态模式（State Pattern）
+ */
+public class StatePatternDemo {
+
+    public static void main(String[] args) {
+        Context context = new Context();
+
+        StartState startState = new StartState();
+        startState.doAction(context);
+
+        System.out.println(context.getState().toString());
+
+        StopState stopState = new StopState();
+        stopState.doAction(context);
+
+        System.out.println(context.getState().toString());
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/state/StopState.java

+package cn.datax.learning.design.patterns.behavioral.state;
+
+public class StopState implements State {
+
+    public void doAction(Context context) {
+        System.out.println("Player is in stop state");
+        context.setState(this);
+    }
+
+    public String toString() {
+        return "Stop State";
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/Context.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+public class Context {
+
+    private Strategy strategy;
+
+    public Context() {}
+
+    public void SetStrategy(Strategy strategy) {
+        this.strategy = strategy;
+    }
+
+    public int executeStrategy(int num1, int num2) {
+        return strategy.doOperation(num1, num2);
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/OperationAdd.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+public class OperationAdd implements Strategy {
+
+    @Override
+    public int doOperation(int num1, int num2) {
+        return num1 + num2;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/OperationMultiply.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+public class OperationMultiply implements Strategy {
+
+    @Override
+    public int doOperation(int num1, int num2) {
+        return num1 * num2;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/OperationSubstract.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+public class OperationSubstract implements Strategy {
+
+    @Override
+    public int doOperation(int num1, int num2) {
+        return num1 - num2;
+    }
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/Strategy.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+public interface Strategy {
+
+    public int doOperation(int num1, int num2);
+}

datax-learning/design-patterns/src/main/java/cn/datax/learning/design/patterns/behavioral/strategy/StrategyPatternDemo.java

+package cn.datax.learning.design.patterns.behavioral.strategy;
+
+/**
+ * 策略模式（Strategy Pattern）
+ */
+public class StrategyPatternDemo {
+
+    public static void main(String[] args) {
+        Context context = new Context();
+        context.SetStrategy(new OperationAdd());
+        System.out.println("10 + 5 = " + context.executeStrategy(10, 5));
+        context.SetStrategy(new OperationSubstract());
+        System.out.println("10 - 5 = " + context.executeStrategy(10, 5));
+        context.SetStrategy(new OperationMultiply());          System.out.println("10 * 5 = " + context.executeStrategy(10, 5));
+    }
+}