command added

Author: maciej-nowak

command/README.md

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+# Command
+This is repository of http://androidcode.pl blog. It Shows uses of Command in Android. It is a part of Design Patterns - Command post in the blog.

command/example/Main.java

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+public class Main {
+
+	public static void main() {
+		//user navigate to account's orders view
+		AccountManager accountManager = new AccountManager();
+		OrderManager orderManager = new OrderManager();
+
+		//user create and execute single order
+		accountManager.takeOrder(new Loan(orderManager, 10000, 90)); //authorize and execute
+
+		//user decided to create orders and authorizate all of them once
+		accountManager.addOrder(new Transfer(orderManager, "12 3456 7890", 500, "For trip"));
+		accountManager.addOrder(new Transfer(orderManager, "30 4050 6070", 500, "Auction nr 987"));
+		accountManager.addOrder(new StandingOrder(orderManager, "11 2222 3333", 80, "Netflix"));
+
+		//authorize and take all orders
+		accountManager.takeOrders();
+	}
+}

command/example/command/Loan.java

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+public class Loan implements Order {
+
+    private OrderManager manager;
+    private int amount, repaymentDays;
+
+    public Loan(OrderManager manager, int amount, repaymentDays) {
+        this.manager = manager;
+    }
+    
+    @Override
+    public void execute() {
+        manager.takeLoan(amount, repaymentDays);
+    }
+}

command/example/command/Order.java

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+interface Order {
+
+    void execute();
+}

command/example/command/StandingOrder.java

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+public class StandingOrder implements Order {
+
+    private OrderManager manager;
+    private String recipient;
+    private int amount, intervalDays;
+
+    public StandingOrder(OrderManager manager, String recipient, int amount, int intervalDays) {
+        this.manager = manager;
+    }
+    
+    @Override
+    public void execute() {
+        manager.scheduleStandingOrder(recipient, amount, intervalDays);
+    }
+}

command/example/command/Transfer.java

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+public class Transfer implements Order {
+
+    private OrderManager manager;
+    private String recipient, title;
+    private int amount;
+
+    public Transfer(OrderManager manager, String recipient, int amount, String title) {
+        this.manager = manager;
+    }
+
+    @Override
+    public void execute() {
+        manager.transferMoney(recipient, amount, title);
+    }
+}

command/example/dummy/Log.java

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+public class Log {
+
+	//fields and constructors
+	
+	public static void log(String text) {
+		//log text
+	}
+
+	//other methods
+}

command/example/invoker/AccountManager.java

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+public class AccountManager {
+
+    private List<Order> orders = new ArrayList<>();
+
+    public void takeOrder(Order order) {
+    	//authorize
+    	//if authorization success then execue order
+    	order.execute();
+    }
+
+    public void takeOrders() {
+    	//authorize
+    	//if authorization success then execue orders
+        for(Order order : orders) 
+    		order.execute();
+    }
+
+    public void addOrder(Order order) {
+    	orders.add(order);
+    }
+
+    public void clearOrders() {
+    	orders.clear();
+    }
+}

command/example/receiver/OrderManager.java

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+public class OrderManager {
+
+    //constructors and fields
+
+    public void scheduleStandingOrder(String recipient, int amount, int intervalDays) {
+        //do action
+        Log.log("Standing order to: " + recipient + " for: " + amount + " with interval: " + intervalDays + " days");
+        //save in history
+    }
+
+    public void transferMoney(String recipient, int amount, String title) {
+        //do action
+        Log.log("Transfer to: " + recipient + "for: " + amount + " with title: " + title);
+        //save in history
+    }
+
+    public void takeLoan(int amount, int repaymentDays) {
+        //do action
+        Log.log("Loan for: " + amount + " to repayment until: " + manager.getRepaymentDate(repaymentDays));
+        //save in history
+    }
+
+    public String getRepaymentDate(int repaymentDays) {
+        return LocalDateTime.now().plusDays(repaymentDays).toString();
+    }
+}

command/pattern/Invoker.java

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+public class Invoker {
+
+    //could be list of commands to provide additional history control if needed
+    private Command command;
+
+    public void setCommand(Command command) {
+        this.command = command;
+    }
+
+    public void start(Command command) {
+        command.execute();
+    }
+}