Sample of Java Pattern -- Template Method

EmailTemplate.java

package templatemethod;

import javax.mail.*;
import javax.mail.internet.*;

public abstract class EmailTemplate {
    public void send(String smtpHostName, String smtpPort, String smtpAuthUser, String smtpAuthPwd, String[] recipients, String subject,String message, String from){
        MimeMessage msg = connect(smtpHostName, smtpPort, smtpAuthUser, smtpAuthPwd);
        try {
            InternetAddress addressFrom = new InternetAddress(from);
            msg.setFrom(addressFrom);

            InternetAddress[] addressTo = new InternetAddress[recipients.length];
            for (int i = 0; i < recipients.length; i++) {
                addressTo[i] = new InternetAddress(recipients[i]);
            }
            msg.setRecipients(Message.RecipientType.TO, addressTo);

            msg.setSubject(subject);
            msg.setContent(message, "text/html");
            Transport.send(msg);
        } catch (MessagingException e) {
            System.out.println("Could not send this email, title=" + subject + " addressTo=" + recipients[0] + ", please check the email server connection.");
        }
    }
    
    protected abstract MimeMessage connect(String smtpHostName, String smtpPort, String smtpAuthUser, String smtpAuthPwd);
}

GeneralEmailService.java

package templatemethod;

import java.security.Security;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Session;
import javax.mail.internet.MimeMessage;

import templatemethod.GoogleEmailService.SMTPAuthenticator;

public class GeneralEmailService extends EmailTemplate{
    private String smtpAuthUser;
    private String smtpAuthPwd;
    protected MimeMessage connect(String smtpHostName, String smtpPort, String smtpAuthUser, String smtpAuthPwd){
        
        this.smtpAuthUser = smtpAuthUser;
        this.smtpAuthPwd = smtpAuthPwd;
        
        boolean debug = false;

        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", "smtp");
        props.setProperty("mail.host", smtpHostName);
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", smtpPort);
        props.setProperty("mail.smtp.quitwait", "false");

        Authenticator auth = new SMTPAuthenticator();
        Session session = Session.getDefaultInstance(props, auth);

        session.setDebug(debug);

        MimeMessage msg = new MimeMessage(session);
        
        return msg;
        
    }
    
    private class SMTPAuthenticator extends javax.mail.Authenticator {
        public PasswordAuthentication getPasswordAuthentication() {
            String username = smtpAuthUser;
            String password = smtpAuthPwd;
            return new PasswordAuthentication(username, password);
        }
    }


}

GoogleEmailService.java

package templatemethod;

import java.security.Security;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.internet.MimeMessage;

public class GoogleEmailService extends EmailTemplate{
    private String smtpAuthUser;
    private String smtpAuthPwd;
    protected MimeMessage connect(String smtpHostName, String smtpPort, String smtpAuthUser, String smtpAuthPwd){
        
        this.smtpAuthUser = smtpAuthUser;
        this.smtpAuthPwd = smtpAuthPwd;
        
        boolean debug = false;

        Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());

        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", "smtp");
        props.setProperty("mail.host", smtpHostName);
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", smtpPort);
        props.setProperty("mail.smtp.quitwait", "false");

        props.put("mail.smtp.socketFactory.port", smtpPort);
        props.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "false");

        Authenticator auth = new SMTPAuthenticator();
        Session session = Session.getDefaultInstance(props, auth);

        session.setDebug(debug);

        MimeMessage msg = new MimeMessage(session);
        
        return msg;
        
    }
    
    private class SMTPAuthenticator extends javax.mail.Authenticator {
        public PasswordAuthentication getPasswordAuthentication() {
            String username = smtpAuthUser;
            String password = smtpAuthPwd;
            return new PasswordAuthentication(username, password);
        }
    }

}

TemplateMethodTest.java

package templatemethod;

public class TemplateMethodTest {

    public static void main(String[] args) {
        String smtpHostName = "";
        String smtpPort = "";
        String smtpAuthUser = "";
        String smtpAuthPwd = "";
        String[] recipients = {""};
        String subject = "";
        String message = "";
        String from = "";
        EmailTemplate googleEmailService = new GoogleEmailService();
        googleEmailService.send(smtpHostName, smtpPort, smtpAuthUser, smtpAuthPwd, recipients, subject, message, from);
        EmailTemplate generalEmailService = new GeneralEmailService();
        generalEmailService.send(smtpHostName, smtpPort, smtpAuthUser, smtpAuthPwd, recipients, subject, message, from);
    }

}

you may download the source code.

Sample of Java Pattern -- Façade

Customer.java

package facade;

public class Customer {
    private String name;
    private String address;
    private Order order;
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
    
    public Order getOrder() {
        return order;
    }

    public void setOrder(Order order) {
        this.order = order;
    }
    
    public void save(){
        
    }

}

Order.java

package facade;

public class Order {
    private String sku;

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }
    
    public void save(){
        
    }
}

CustomerFacade.java

package facade;

public class CustomerFacade {
    public void placeOrder(String customerName, String customerAddress, String sku){
        Customer customer = new Customer();
        customer.setName(customerName);
        customer.setAddress(customerAddress);
        Order order = new Order();
        order.setSku(sku);
        customer.setOrder(order);
        customer.save();
        order.save();
    }
}

FacadeTest.java

package facade;

public class FacadeTest {

    public static void main(String[] args) {
        CustomerFacade customerFacade = new CustomerFacade();
        customerFacade.placeOrder("customerName", "customerAddress", "sku");
    }

}

you may download the source code.

Debug Tomcat and JBoss Web-application in Eclipse

1. configure tomcat to allow remote debugging
ensure the startup.bat includes:

set JPDA_ADDRESS=8000
set JPDA_TRANSPORT=dt_socket

or startup.sh includes:

export JPDA_ADDRESS=8000
export JPDA_TRANSPORT=dt_socket

and update the execute line to inlcude(the first line for startup.bat, the second line for startup.sh):

call "%EXECUTABLE%" jpda start %CMD_LINE_ARGS%
exec "$PRGDIR"/"$EXECUTABLE" jpda start "$@"

2. configure jboss to allow remote debugging
ensure the JAVA_OPTS in your jboss run.sh or run.bat includes:

-Xdebug -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=y

3. configure eclipse to remote debug
go into 'debug' in eclipse and new a remote debug application, remember apply 'port number' to web application server debug port, in this case, this port number is 8787, not 8080.

Sample of Java Pattern -- Adapter

LegacyModel.java

package adapter;

public class LegacyModel {
    public void ins(String sku){
        System.out.println("call ins method.");
    }
}

ModernModel.java

package adapter;

public interface ModernModel {
    public void save(Order order);
}

ModernModelAdapter.java

package adapter;

public class ModernModelAdapter implements ModernModel{
    private LegacyModel legacyModel;
    
    public ModernModelAdapter(LegacyModel legacyModel) {
        super();
        this.legacyModel = legacyModel;
    }
    
    public void save(Order order){
        String sku = order.getSku();
        legacyModel = new LegacyModel();
        legacyModel.ins(sku);
    }
}

Order.java

package adapter;

public class Order {
    private String sku;

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }
    
}

AdapterTest.java

package adapter;

public class AdapterTest {
    public static void main(String[] args) {
        LegacyModel legacy = new LegacyModel(); 
        Order order = new Order();
        order.setSku("sku");
        ModernModelAdapter adapter = new ModernModelAdapter(legacy);
        adapter.save(order);
    }
}

you may download the source code.

Sample of Java Pattern -- Command

Command.java

package command;

public interface Command {
  public void execute();
}

ConfirmCommand.java

package command;

public class ConfirmCommand implements Command {

  private EmailService emailService;

  public ConfirmCommand(){}

  public void execute() {
      emailService = new EmailService();
      emailService.confirmMeeting();
  }

}

CancelCommand.java

package command;

public class CancelCommand implements Command {

  private EmailService emailService;

  public CancelCommand(){}

  public void execute() {
      emailService = new EmailService();
      emailService.cancelMeeting();
  }

}

EmailService.java

package command;

public class EmailService {

  public EmailService(){}

  public void cancelMeeting(){
      System.out.println("send cacellation email");
  }

  public void confirmMeeting(){
      System.out.println("send confirmation email");
  }

}

Invoker.java

package command;

public class Invoker {
  private Command command;

  public Invoker(){
  }

  public void setCommand(Command command){
      this.command = command;
  }

  public void executeCommand(){
      this.command.execute();
  }
}

CommandTest.java

package command;

public class CommandTest {

  public static void main(String[] args) {
      CancelCommand cancelCommand = new CancelCommand();
      ConfirmCommand confirmCommand = new ConfirmCommand();
      Invoker invoker = new Invoker();
      invoker.setCommand(confirmCommand);
      invoker.executeCommand();
      invoker.setCommand(cancelCommand);
      invoker.executeCommand();
  }

}

you can download the source code .

Sample of Java Pattern -- Singleton

Utils.java

package singleton;

public class Utils {
    
    private Utils(){}
    
    private static Utils instance = new Utils();
    
    public static Utils getInstance() {
        return instance;
    }
    
    public void println(String str){
        System.out.println(str);
    }

    public static void main(String[] args) {
        Utils.getInstance().println("Hello");
    }
}

you may download the source code.