Importend Hints

Not all service technology can the same. You can avoid problems with this hints.

• The transfer object (method parameters and return value) must be simple Java types or JavaBeans with below restriction:
  • Default constructor
  • setter/getter methods
  • setter/getter use interfaces by lists and maps (java.util.Collection, java.util.Map) and not the implementations (e.g. java.util.ArrayList, java.util.HashMap)
  • ...
  Example - class:

  public class Customer {
  
  	private String name = null;
  	private List cars = null;
  	
  	public Customer() {
  	}
  	
  	public String getName() {
  		return this.name;
  	}
  	public void setName(String name) {
  		this.name = name;
  	}
  	
  	public List getCars() {
  		return this.cars;
  	}
  	public void setCars(List cars) {
  		this.cars = cars;
  	}
  	
  	
  }
  			

• Prefer Datatypes:
  • java.lang.Integer
  • java.lang.Boolean
  • java.lang.String
  • java.lang.Double
  • java.lang.Date
• Don't use overloading from service methods:

  public interface Calculator {
  
  	// FALSE
  	int add(int a, int b);
  	long add(long a, long b);
  	
  	// make two different method names
  	int addInt(int a, int b);
  	long addLong(long a, long b);	
  }
  			

• Every service methods must have one parameter at least and a return value:

  public interface Echo {
  
  	// false
  	String ping();
  	
  	// right
  	String echo(String echoString);
  }
  			

• How can transport logical/business/validation errors with service methods? The service method can throw a Exception that contains an additional class (container) for this errors:

  public class ValidationError implements Serializable {
  	
  	private static final long serialVersionUID = 5930253049442253128L;
  	
  	private int code = 0;
  	private String message = "No message available!";
  
  	public ValidationError() { }
  	public ValidationError(int pvCode, String pvMessage) { 
  		setCode(pvCode);
  		setMessage(pvMessage);
  	}
  	
  	public void setCode(int pvCode) { code = pvCode; }
  	public int getCode() { return code; }
  	
  	public void setMessage(String pvMessage) { message = pvMessage; }
  	public String getMessage() { return message; }
  	
  	public String toString() {
  		return code + " - " + message;
  	}
  }
  
  // and the Exception as container for the ValidationError
  
  public class MyBusinessException extends RuntimeException {
  
  	private static final long serialVersionUID = 3669006021606741955L;
  
  	private List validationErrors = new ArrayList();
  	
  	public MyBusinessException() {}
  	public MyBusinessException(String pvMessage) {
  		super(pvMessage);
  	}
  	public List getValidationErrors() { return validationErrors; }
  	public void setValidationErrors(List pvValidationErrors) { validationErrors = pvValidationErrors; }
  	
  }
  
  // and the business method signature example
  
  public interface BusinessService {
  
  
  	public Object businessServiceMethod(Object arg) throws MyBusinessException;
  }	
  	
  			

• Don't use complex key objects by java.util.Map implementation by transfer objects.