public static void addEventListener()

in src/main/java/org/apache/bsf/util/ReflectionUtils.java [77:186]
79 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);
    }