package bluej.extensions;

import bluej.debugger.DebuggerObject;
import bluej.debugmgr.objectbench.ObjectWrapper;
import bluej.pkgmgr.PkgMgrFrame;
import bluej.views.MethodView;
import bluej.views.View;
import com.sun.jdi.Field;
import com.sun.jdi.ObjectReference;
import com.sun.jdi.ReferenceType;
import java.lang.reflect.Modifier;




| A wrapper for a method of a BlueJ class.
| Allows an extension to invoke a method on an object that is on the BlueJ object bench.
| When values representing types are returned, there are two cases:
| In the case that the returned value is of primitive type (<code>int</code> etc.),
| it is represented in the appropriate Java wrapper type (<code>Integer</code> etc.).
| In the case that the returned value is an object type then an appropriate BObject will
| be returned, allowing the returned object itself to be placed on the BlueJ object bench.
|
| @author Clive Miller, University of Kent at Canterbury, 2002
| @author Damiano Bolla, University of Kent at Canterbury 2003
|
public class BMethod
{       

    
   
   private Identifier parentId;
   
   private MethodView bluej_view;
    
   
   


| Constructor.
|
BMethod ( Identifier aParentId, MethodView i_bluej_view )
   {        
      parentId   = aParentId;
       
      bluej_view = i_bluej_view;     
      }

   
   


| Tests if this method matches against the given signature.
| Returns true if there is a match, false otherwise.
| Pass a zero length parameter array if the method takes no arguments.
|
public boolean matches( String methodName, Class<?>[] parameter )
   {        
      
      if ( methodName == null ) return false;

       
      
      if ( ! methodName.equals(bluej_view.getName() ) ) return false;
     
      Class<?>[] thisArgs = bluej_view.getParameters();

       
      
      if (thisArgs  != null && thisArgs.length  <= 0)  thisArgs  = null;
      if (parameter != null && parameter.length <= 0 ) parameter = null;

       
      
      if ( thisArgs == null && parameter == null ) return true;

      
      if ( thisArgs == null || parameter == null ) return false;

       
      
      if ( thisArgs.length != parameter.length ) return false;
    
       
      for ( int index=0; index<thisArgs.length; index++ ) {
         if ( ! thisArgs[index].isAssignableFrom(parameter[index]) ) {                
            return false;             
            }         
         }

       
      return true;     
      }

    
   


| Returns the class that declares this method.
| Similar to Reflection API
|
public String getDeclaringClass()
   {
      return bluej_view.getClassName();     
      }
    
   
   


| Returns the types of the parameters of this method.
| Similar to Reflection API
|
public Class[] getParameterTypes()
   {
      return bluej_view.getParameters();     
      }
      
   
   


| Returns the name of this method.
| Similar to Reflection API
|
public String getName()
   {
      return bluej_view.getName();     
      }
    
   
   


| Returns the return type of this method
| Similar to Reflection API
|
public Class getReturnType()
   {
      View aView = bluej_view.getReturnType();
      return aView.getViewClass();     
      }
    
   
   


| Returns the modifiers for this method.
| The <code>java.lang.reflect.Modifier</code> class can be used to decode the modifiers.
|
public int getModifiers()
   {
      return bluej_view.getModifiers();     
      }

   
   


| Invoke this method on the given object. Note that this method should
| not be called from the AWT/Swing event-dispatching thread.
|
| <p>The arguments passed in the initargs array may have any type,
| but the type will determine exactly what is passed to the
| method:
|
| <ul>
| <li>String - the String will be passed directly to the method
| <li>BObject - the object will be passed directly to the method,
|               though it must be on the object bench for this to work
| <li>Anything else - toString() is called on the object and the
|               result is treated as a Java expression, which is
|               evaluated and passed to the method.
| </ul>
|
| <p>An attempt is made to ensure that the argument types are suitable
| for the method. InvocationArgumentException will be thrown if
| the arguments are clearly unsuitable, however some cases will
| generate an InvocationErrorException instead. In such cases no
| expression arguments will be evaluated.
|
| <p>If the method invoked is <code>public static void main(String [] args)</code>, then the invocation will,
| as a side-effect, reset the VM used by BlueJ to run user code in this project, and clear the object bench. This
| behaviour matches the effect of invoking a main method through the BlueJ GUI.
|
| @param onThis The BObject to which the method call should be applied, null if a static method.
| @param params an array containing the arguments, or null if there are none
| @return the resulting Object. It can be a wrapper for a primitive type or a BObject
| @throws ProjectNotOpenException if the project to which this object belongs has been closed by the user.
| @throws PackageNotFoundException if the package to which this object belongs has been deleted by the user.
| @throws InvocationArgumentException if the <code>params</code> don't match the object's arguments.
| @throws InvocationErrorException if an error occurs during the invocation.
|
public Object invoke(BObject onThis, Object[] params) 
       
   throws ProjectNotOpenException, PackageNotFoundException, 
              
   InvocationArgumentException, InvocationErrorException
   {        
      ObjectWrapper instanceWrapper=null;
       
      
      if ( onThis != null ) instanceWrapper = onThis.getObjectWrapper();
        
      PkgMgrFrame  pkgFrame = parentId.getPackageFrame();
       
      DirectInvoker invoker = new DirectInvoker (pkgFrame);
      DebuggerObject result = invoker.invokeMethod (instanceWrapper, bluej_view, params);

      
      
      if (result == null || result.isNullObject()) return null;

      String resultName = invoker.getResultName();

      ObjectReference objRef = result.getObjectReference();
      ReferenceType type = objRef.referenceType();

       
      
      Field thisField = type.fieldByName ("result");
      if ( thisField == null ) return null;

       
      
      return BField.doGetVal(pkgFrame, resultName, objRef.getValue(thisField));     
      }
    
  
   
   


| Returns a string representing the return type, name and signature of this method
|
public String toString()
   {
      Class<?>[] signature = getParameterTypes();
       
      String sig = "";
       
      for (int i=0; i<signature.length; i++) {
         sig += signature[i].getName() + (i==signature.length-1?"":", ");         
         }
      String mod = Modifier.toString (getModifiers());
      if (mod.length() > 0) mod += " ";
      return mod+getReturnType()+" "+getName()+"("+sig+")";     
      } 
   }