public static void addEventListener()

in src/main/java/org/apache/bsf/util/ReflectionUtils.java [88:203]
86 lines of code
12 McCabe index (conditional complexity)

  public static void addEventListener (final Object source, final String eventSetName,
                       final EventProcessor processor)
       throws IntrospectionException, IllegalArgumentException,
              IllegalAccessException, InstantiationException,
              InvocationTargetException {
    // find the event set descriptor for this event
    final BeanInfo bi = Introspector.getBeanInfo (source.getClass ());

    final EventSetDescriptor arrESD[]=bi.getEventSetDescriptors ();
    final EventSetDescriptor esd=(EventSetDescriptor) findFeatureByName ("event", eventSetName, arrESD);

    if (esd == null)        // no events found, maybe a proxy from OpenOffice.org?
        {
          String errMsg="event set '" + eventSetName +"' unknown for source type '" + source.getClass () + "': ";
          if (arrESD.length==0)     // no event sets found in class!
          {
              errMsg=errMsg+"class does not implement any event methods following Java's event pattern!";
          }
          else
          {
              // errMsg=errMsg+"class defines the following event set(s): {";
              errMsg=errMsg+"class defines the following event set(s): ";

              // sort ESD by Name
              final TreeSet ts=new TreeSet(new Comparator () {
                          public int    compare(final Object o1, final Object o2) {return ((EventSetDescriptor)o1).getName().compareToIgnoreCase(((EventSetDescriptor)o2).getName());}
                          public boolean equals(final Object o1, final Object o2) {return ((EventSetDescriptor)o1).getName().equalsIgnoreCase   (((EventSetDescriptor)o2).getName());}
                         });

              for (int i=0;i<arrESD.length;i++)
              {
                  ts.add(arrESD[i]);
              }
              final Iterator it=ts.iterator();    // get iterator

              int i=0;
              while (it.hasNext())          // iterate in sorted order
              {
                  final EventSetDescriptor tmpESD=(EventSetDescriptor) it.next();

                  if (i>0)
                  {
                      errMsg=errMsg+", ";
                  }
                  errMsg=errMsg+"\n\t"+'\''+tmpESD.getName()+"'={";  // event set name


                    // iterate over listener methods and display their names in sorted order
                  final Method m[]=tmpESD.getListenerMethods();
                  final TreeSet tsM=new TreeSet(new Comparator () {
                          public int    compare(final Object o1, final Object o2) {return ((Method)o1).getName().compareToIgnoreCase(((Method)o2).getName());}
                          public boolean equals(final Object o1, final Object o2) {return ((Method)o1).getName().equalsIgnoreCase   (((Method)o2).getName());}
                         });

                  for (int j=0;j<m.length;j++)
                  {
                      tsM.add(m[j]);
                  }
                  final Iterator itM=tsM.iterator();

                  int j=0;
                  while (itM.hasNext())
                  {
                      if (j>0)
                      {
                          errMsg=errMsg+',';
                      }
                      errMsg=errMsg+'\''+((Method) itM.next()).getName()+'\'';
                      j++;
                  }
                  errMsg=errMsg+'}';    // close event method set
                  i++;
              }

              errMsg=errMsg+".";       // close set of event sets
          }
          throw new IllegalArgumentException (errMsg);
    }

    // get the class object for the event
    final Class listenerType=esd.getListenerType(); // get ListenerType class object from EventSetDescriptor

    // find an event adapter class of the right type
    final Class adapterClass = EventAdapterRegistry.lookup (listenerType);
    if (adapterClass == null) {
      throw new IllegalArgumentException ("event adapter for listener type " +
                          "'" + listenerType + "' (eventset " +
                          "'" + eventSetName + "') unknown");
    }

    // create the event adapter and give it the event processor
    final EventAdapter adapter = (EventAdapter) adapterClass.newInstance ();
    adapter.setEventProcessor (processor);

    // bind the adapter to the source bean
    Method addListenerMethod;
    Object[] args;
    if (eventSetName.equals ("propertyChange") ||
        eventSetName.equals ("vetoableChange")) {
      // In Java 1.2, beans may have direct listener adding methods
      // for property and vetoable change events which take the
      // property name as a filter to be applied at the event source.
      // The filter property of the event processor should be used
      // in this case to support the source-side filtering.
      //
      // ** TBD **: the following two lines need to change appropriately
          addListenerMethod = esd.getAddListenerMethod ();
      args = new Object[] {adapter};
    }
        else
        {
          addListenerMethod = esd.getAddListenerMethod ();
      args = new Object[] {adapter};
    }
    addListenerMethod.invoke (source, args);
  }