Strategy example in java(GoF design pattern) (not responsible for this code)

gistfile1.java

package br.padroes.gof.comportamental.strategy;  



public class ClienteStrategy {              

    public static void main(String[] args) {         Context context;           

    // Three contexts following different strategies         

    

    context = new Context(new ConcreteStrategyAdd());         

    int resultA = context.executeStrategy(3,4);         

    showResultado(resultA);           

    context = new Context(new ConcreteStrategySubtract());         

    int resultB = context.executeStrategy(3,4);         

    showResultado(resultB);           

    context = new Context(new ConcreteStrategyMultiply());        

    int resultC = context.executeStrategy(3,4);         

    showResultado(resultC);     

    }          

    public static void showResultado(int resultado) {         

        System.out.println("Resultado: " + resultado);     

        }      

    } 

gistfile2.java

package br.padroes.gof.comportamental.strategy;  

public interface Strategy {     

    int execute(int a, int b); 

} 

gistfile3.java

package br.padroes.gof.comportamental.strategy;  



public class Context {       

    private Strategy strategy;       

    // Constructor     

    public Context(Strategy strategy) {         

        this.strategy = strategy;     

        }       

    public int executeStrategy(int a, int b) {         

        return strategy.execute(a, b);     

    }       

} 

gistfile4.java

package br.padroes.gof.comportamental.strategy;  

public class ConcreteStrategySubtract implements Strategy {      

    public int execute(int a, int b) {         

        System.out.println("Called ConcreteStrategyB's execute()");         

        return a - b;  

        // Do a subtraction with a and b     

        }   

    } 

gistfile5.java

package br.padroes.gof.comportamental.strategy;  

public class ConcreteStrategyAdd implements Strategy {       

    public int execute(int a, int b) {         

        System.out.println("Called ConcreteStrategyA's execute()");         

        return a + b;  

        // Do an addition with a and b     

        }   

    }