24.2.1.1 The @MaxNumber and @Random Qualifier Interfaces

The @MaxNumber qualifier interface is defined as follows:

package guessnumber;

import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.ElementType.TYPE;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Target;
import javax.inject.Qualifier;

@Target({TYPE, METHOD, PARAMETER, FIELD})
@Retention(RUNTIME)
@Documented
@Qualifier
public @interface MaxNumber {
}

The @Random qualifier interface is defined as follows:

package guessnumber;

import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.ElementType.TYPE;
import java.lang.annotation.Retention;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Target;
import javax.inject.Qualifier;

@Target({TYPE, METHOD, PARAMETER, FIELD})
@Retention(RUNTIME)
@Documented
@Qualifier
public @interface Random {
}

24.2.1.2 The Generator Managed Bean

The Generator managed bean contains the two producer methods for the application. The bean has the @ApplicationScoped annotation to specify that its context extends for the duration of the user's interaction with the application:

package guessnumber;

import java.io.Serializable;
import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.inject.Produces;

@ApplicationScoped
public class Generator implements Serializable {

    private static final long serialVersionUID = -7213673465118041882L;

    private final java.util.Random random = 
        new java.util.Random( System.currentTimeMillis() );

    private final int maxNumber = 100;

    java.util.Random getRandom() {
        return random;
    }

    @Produces @Random int next() {
        return getRandom().nextInt(maxNumber + 1);
    }

    @Produces @MaxNumber int getMaxNumber() {
        return maxNumber;
    }

}

24.2.1.3 The UserNumberBean Managed Bean

The UserNumberBean managed bean, the managed bean for the JavaServer Faces application, provides the basic logic for the game. This bean does the following:

• Implements setter and getter methods for the bean fields

• Injects the two qualifier objects

• Provides a reset method that allows you to begin a new game after you complete one

• Provides a check method that determines whether the user has guessed the number

• Provides a validateNumberRange method that determines whether the user's input is correct

The bean is defined as follows:

package guessnumber;

import java.io.Serializable;
import javax.annotation.PostConstruct;
import javax.enterprise.context.SessionScoped;
import javax.enterprise.inject.Instance;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.component.UIInput;
import javax.faces.context.FacesContext;
import javax.inject.Inject;
import javax.inject.Named;

@Named
@SessionScoped
public class UserNumberBean implements Serializable {

    private static final long serialVersionUID = -7698506329160109476L;

    private int number;
    private Integer userNumber;
    private int minimum;
    private int remainingGuesses;

    @MaxNumber
    @Inject
    private int maxNumber;

    private int maximum;

    @Random
    @Inject
    Instance<Integer> randomInt;

    public UserNumberBean() {
    }

    public int getNumber() {
        return number;
    }

    public void setUserNumber(Integer user_number) {
        userNumber = user_number;
    }

    public Integer getUserNumber() {
        return userNumber;
    }

    public int getMaximum() {
        return (this.maximum);
    }

    public void setMaximum(int maximum) {
        this.maximum = maximum;
    }

    public int getMinimum() {
        return (this.minimum);
    }

    public void setMinimum(int minimum) {
        this.minimum = minimum;
    }

    public int getRemainingGuesses() {
        return remainingGuesses;
    }

    public String check() throws InterruptedException {
        if (userNumber > number) {
            maximum = userNumber - 1;
        }
        if (userNumber < number) {
            minimum = userNumber + 1;
        }
        if (userNumber == number) {
            FacesContext.getCurrentInstance().addMessage(null, 
                new FacesMessage("Correct!"));
        }
        remainingGuesses--;
        return null;
    }

    @PostConstruct
    public void reset() {
        this.minimum = 0;
        this.userNumber = 0;
        this.remainingGuesses = 10;
        this.maximum = maxNumber;
        this.number = randomInt.get();
    }

    public void validateNumberRange(FacesContext context, 
                                    UIComponent toValidate, 
                                    Object value) {
        int input = (Integer) value;

        if (input < minimum || input > maximum) {
            ((UIInput) toValidate).setValid(false);

            FacesMessage message = new FacesMessage("Invalid guess");
            context.addMessage(toValidate.getClientId(context), message);
        }
    }
}

24.2.3.1 To Build, Package, and Deploy the guessnumber-cdi Example Using NetBeans IDE

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. From the File menu, choose Open Project.

3. In the Open Project dialog box, navigate to:

   tut-install/examples/cdi
   

4. Select the guessnumber-cdi folder.

5. Click Open Project.

6. In the Projects tab, right-click the guessnumber-cdi project and select Build.

   This command builds and packages the application into a WAR file, guessnumber-cdi.war, located in the target directory, and then deploys it to GlassFish Server.

24.2.3.2 To Build, Package, and Deploy the guessnumber-cdi Example Using Maven

1. Make sure that GlassFish Server has been started (see Starting and Stopping GlassFish Server).

2. In a terminal window, go to:

   tut-install/examples/cdi/guessnumber-cdi/
   

3. Enter the following command to deploy the application:

   mvn install
   

   This command builds and packages the application into a WAR file, guessnumber-cdi.war, located in the target directory, and then deploys it to GlassFish Server.

24.2.3.3 To Run the guessnumber Example

1. In a web browser, enter the following URL:

   http://localhost:8080/guessnumber-cdi
   

   The Guess My Number page opens.

2. On the Guess My Number page, enter a number in the Number field and click Guess.

   The minimum and maximum values are modified, along with the remaining number of guesses.

3. Keep guessing numbers until you get the right answer or run out of guesses.

   If you get the right answer or run out of guesses, the input field and Guess button are grayed out.

4. Click Reset to play the game again with a new random number.