trouble with reflection

[anitha nair]

Hi forum,

Please help me out with this problem.

I am getting the parameter types of a method in a class as

Class[] parameterTypes=method.getPrameterTypes();

I need to test if the parameter types are of primitive types i.e int or String or long etc...If its not it should show a message box.
For that i used the following code.The trouble is that it doesnt seems to test the whole conditions.It seems to check only the first condition and for all other conditions it gives a negative result.i.e for String,long,float etc it shows the message box whereas it should be executing else condition instead.Please tell me whats wrong with it.

 
                        for (int i = 0; i < numOfParameters; i++)
                        {
                                                        
                             if ( ! (parameterTypes[i].toString().equals("int") || parameterTypes[i].toString().equals("Integer"))||
                                       
                               (parameterTypes[i].toString().equals("long") || parameterTypes.toString().equals("Long"))||
                                 
                          (parameterTypes[i].toString().equals("java.lang.String")|| 
                                
                          (parameterTypes[i].toString().equals("float") || parameterTypes[i].toString().equals("Float"))||
                                
                         (parameterTypes[i].toString().equals("boolean") || parameterTypes[i].equals("Boolean")))
                                
                          {
                            JOptionPane.showMessageDialog(null, "Do Not Support The Data Type","Error",JOptionPane.ERROR_MESSAGE);
                             break;
                          }
else{---------------------------}
                          

Thank you all in advance.
[ August 08, 2006: Message edited by: Bear Bibeault ]

[Ulf Dittmer]

Are you sure that Class.toString returns the result you're expecting? toString returns a string representation, but not necessarily the one you would expect. Try the getName method instead. Also, don't call it 9 times - call it once, and store the result in a variable.

[James Sabre]

It would seem much better to test the class of the arguments rather than the class name. You can then simplify the problem to checking if the class of the parameters is in an allowable set. For example -

  
import java.util.*;
import java.lang.reflect.*;
 
public class Fred905
{   
    static final Set<Type> allowedClasses = new HashSet<Type>();
    static
    {
        allowedClasses.add(long.class);
        allowedClasses.add(int.class);
        allowedClasses.add(double.class);
        allowedClasses.add(float.class);
        allowedClasses.add(String.class);
    }
    
    public static boolean paramsAreAllPrimitive(Method method)
    {
        Type[] types = method.getGenericParameterTypes();
        for (Type type : types)
        {
            if (!allowedClasses.contains(type))
                return false;
        }
        return true;
    }
    
    public static void aMethod(int x, String y)
    {
        
    }
    
    public void bMethod(float x, String y, long z)
    {
        
    }
    
    public void cMethod(float x, String y, Double z)
    {
        
    }
    
    public static void main(String[] args)
    {
        for (Method method : Fred905.class.getMethods())
        {
            System.out.println(method.getName() + "\t" + paramsAreAllPrimitive(method));
        }
    }
}
  

[James Sabre]

I have just updated teh code so theat it woll work with Java prior to 1.5.

   
import java.util.*;
import java.lang.reflect.*;
 
public class Fred905
{   
    static final Set<Class> allowedClasses = new HashSet<Class>();
    static
    {
        allowedClasses.add(long.class);
        allowedClasses.add(int.class);
        allowedClasses.add(double.class);
        allowedClasses.add(float.class);
        allowedClasses.add(String.class);
    }
    
    public static boolean paramsAreAllPrimitive(Method method)
    {
        Class[] parameterClasses = method.getParameterTypes();
        for (Class clazz : parameterClasses)
        {
            if (!allowedClasses.contains(clazz))
                return false;
        }
        return true;
    }
    
    public static void aMethod(int x, String y)
    {
        
    }
    
    public void bMethod(float x, String y, long z)
    {
        
    }
    
    public void cMethod(float x, String y, Double z)
    {
        
    }
    
    public static void main(String[] args)
    {
        for (Method method : Fred905.class.getMethods())
        {
            System.out.println(method.getName() + "\t" + paramsAreAllPrimitive(method));
        }
    }
}
 
 

[Singhal Anuj]

Hi,

I do not think this code will compile in java 1.4

Regards,
Anuj

[Joanne Neal]

Originally posted by anitha nair:

I need to test if the parameter types are of primitive types i.e int or String or long etc...

Just for the record, String is not a primitive type.

[James Sabre]

Probably a waste of time since the OP did not seem interested but ...

   
 
import java.util.*;
import java.lang.reflect.*;
 
public class Fred905
{   
    static final Set allowedClasses = new HashSet();
    static
    {
        allowedClasses.add(long.class);
        allowedClasses.add(int.class);
        allowedClasses.add(double.class);
        allowedClasses.add(float.class);
        allowedClasses.add(String.class);
    }
    
    public static boolean paramsAreAllPrimitive(Method method)
    {
        Class[] parameterClasses = method.getParameterTypes();
        for (int index = 0; index < parameterClasses.length; index++)
        {
            if (!allowedClasses.contains(parameterClasses[index]))
                return false;
        }
        return true;
    }
    
    public static void aMethod(int x, String y)
    {
        
    }
    
    public void bMethod(float x, String y, long z)
    {
        
    }
    
    public void cMethod(float x, String y, Double z)
    {
        
    }
    
    public static void main(String[] args)
    {
        final Method[] methods = Fred905.class.getMethods();
        for (int index = 0; index < methods.length; index++)
        {
            Method method = methods[index];
            System.out.println(method.getName() + "\t" + paramsAreAllPrimitive(method));
        }
    }
}
 

[ August 08, 2006: Message edited by: James Sabre ]
[ August 08, 2006: Message edited by: James Sabre ]