Pattern Strategy

src/strategy/Annotation.txt

@@ -1,4 +1,8 @@
 ##############################
-#       STRATEGY             #
+#         STRATEGY           #
 ##############################
 
+- We use interfaces to use polymorphism in our doing.
+
+- We broke the use of several 'ifs', with that we can invoke a method that according to its 
+instance it can call a method implemented differently than another instance.

src/strategy/Budget.java

@@ -0,0 +1,16 @@
+package strategy;
+
+public class Budget {
+
+	private double value;
+
+	Budget(double value) {
+		super();
+		this.value = value;
+	}
+
+	public double getValue() {
+		return value;
+	}
+
+}

src/strategy/StrategyMain.java

@@ -3,7 +3,22 @@
 public class StrategyMain {
 
 	public static void main(String[] args) {
-		System.out.println("Begin Test Strategy");
+		System.out.println("--------------------------------------------- Begin Test Strategy");
+
+		Budget budget = new Budget(100);
+
+		Tax icms = new TaxICMS();
+		Tax inss = new TaxINSS();
+
+		TaxCalculator taxCalculator = new TaxCalculator();
+
+		// Here we passes a Strategy for Calculator Tax, and in execution time, we will know what will be executed ICMS or INSS
+		taxCalculator.calculate(budget, icms);//10
+		taxCalculator.calculate(budget, inss);//20
+
+		// I can create any Tax and not broken my code, because I using pattern Strategy, using much Interfaces
+
+		System.out.println("--------------------------------------------- End Test Strategy");
 	}
 
 }

src/strategy/Tax.java

@@ -0,0 +1,7 @@
+package strategy;
+
+public interface Tax {
+
+	public double calculate(Budget budget);
+
+}

src/strategy/TaxCalculator.java

@@ -0,0 +1,11 @@
+package strategy;
+
+public class TaxCalculator {
+
+	public void calculate(Budget budget, Tax anyTax) {
+
+		double valueResult = anyTax.calculate(budget);
+		System.out.println("Value: " + valueResult + ". Class @Override: " + anyTax.getClass().getSimpleName());
+	}
+
+}

src/strategy/TaxICMS.java

@@ -0,0 +1,10 @@
+package strategy;
+
+public class TaxICMS implements Tax {
+
+	@Override
+	public double calculate(Budget budget) {
+		return budget.getValue() * 0.1;
+	}
+
+}

src/strategy/TaxINSS.java

@@ -0,0 +1,10 @@
+package strategy;
+
+public class TaxINSS implements Tax {
+
+	@Override
+	public double calculate(Budget budget) {
+		return budget.getValue() * 0.2;
+	}
+
+}