Description Matthew Ong 2012-06-13 11:20:21 EDT

With reference to the discussion shown within this posting.

http://aspectj.2085585.n4.nabble.com/How-to-add-methods-to-java-lang-String-td4650376.html#a4650390

Case 1) introduced a new method into the calling class without any issue.
public final class Point{}

public aspect Point
{
    // a new method is introduced into the Point Class.
    public String Point.toLongString(){
       return "### FROM ASPECT ###";
    }
}

public class Main{
  public static void main(String[] args){
      Point p1 = new Point();

      // This line below works without any error.
      System.out.println("p1.toLongString =" +p1.toLongString());      
      System.out.println("p1 =" + p1);
  }
} 

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Case 2) allows the overriding of the call weaving also without issue.

public aspect JavaLangSystemAspect {
 /**
     * Selects calls to System.currentTimeMillis() occurring within tested code.
     */
    pointcut currentTimeMillis() :            
             call(public long System.currentTimeMillis());

   
    long around() : currentTimeMillis(){
        return 12345;  // overriden method without any privilege 
    }
}

public class SystemUser
{

    public static void MillisUser(){
        // will show only 12345, which is more dangerous than adding new
        // methods into existing class.
        System.out.println("The currentTimeMilis:"+System.currentTimeMillis());
    }
   
    public static void main(String[] args)
    {
        MillisUser(); // will show only 12345
    }

} 
---------------------------------------
<B>However when this class is added causes error in the weaver.</B>
Because I tried to simulate what is being down in Case 1.

// Extends the String class and provide other useful
public privileged aspect StringUtils {

        public String java.lang.String.ltrim(){
                return "TEST LTRIM";
        }
       
        public String java.lang.String.rtrim(){
                return "TEST RTRIM";
        }
       
}

public class Main {
  public static void main(String[] args) {
         String string="ABCDEFG";
         //  Complians with the error shown below
         string=string.ltrim(); // ### SUGGEST that weaving done like call in case 2.
         System.out.println(string);
 }
} 

-----------------------------
Can such introduction be done without weaving the source class but rather at the calling class instead, just like the Pointcut call. 

This might allow existing java..* or javax.* classes within rt.jar untouched.