private CommonDropAdapterAssistant[] pySortAssistants(CommonDropAdapterAssistant[] array) {
    Arrays.sort(array, new Comparator() {
        @Override
        public int compare(Object arg0, Object arg1) {
            CommonDropAdapterAssistant a = (CommonDropAdapterAssistant) arg0;
            CommonDropAdapterAssistant b = (CommonDropAdapterAssistant) arg1;
            // This is to ensure that the PyDev drop assistant will always
            // be chosen over non-PyDev ones, if a conflict ever occurs.
            String id = "org.python.pydev.navigator.actions"; //$NON-NLS-1$
            if (a.getClass().getName().startsWith(id)) {
                return -1;
            }
            if (b.getClass().getName().startsWith(id)) {
                return 1;
            }
            return a.getClass().getName().compareTo(b.getClass().getName());
        }
    });
    return array;
}
 

@Override
public CommonDropAdapterAssistant[] findCommonDropAdapterAssistants(
        Object aDropTarget, TransferData aTransferType) {

    CommonDropAdapterDescriptor[] descriptors = CommonDropDescriptorManager
            .getInstance().findCommonDropAdapterAssistants(aDropTarget,
                    pyContentService);

    if (descriptors.length == 0) {
        return NO_ASSISTANTS;
    }

    if (LocalSelectionTransfer.getTransfer().isSupportedType(aTransferType)
            && LocalSelectionTransfer.getTransfer().getSelection() instanceof IStructuredSelection) {
        return pyGetAssistantsBySelection(descriptors, (IStructuredSelection) LocalSelectionTransfer
                .getTransfer().getSelection());
    }
    return pyGetAssistantsByTransferData(descriptors, aTransferType);
}
 

@Override
public CommonDropAdapterAssistant[] findCommonDropAdapterAssistants(
        Object aDropTarget, IStructuredSelection theDragSelection) {

    CommonDropAdapterDescriptor[] descriptors = CommonDropDescriptorManager
            .getInstance().findCommonDropAdapterAssistants(aDropTarget,
                    pyContentService);

    if (descriptors.length == 0) {
        return NO_ASSISTANTS;
    }

    return pyGetAssistantsBySelection(descriptors, theDragSelection);
}
 

private CommonDropAdapterAssistant[] pyGetAssistantsByTransferData(
        CommonDropAdapterDescriptor[] descriptors,
        TransferData aTransferType) {

    Set assistants = new LinkedHashSet();
    for (int i = 0; i < descriptors.length; i++) {
        CommonDropAdapterAssistant asst = pyGetAssistant(descriptors[i]);
        if (asst.isSupportedType(aTransferType)) {
            assistants.add(asst);
        }
    }
    return pySortAssistants((CommonDropAdapterAssistant[]) assistants
            .toArray(new CommonDropAdapterAssistant[assistants.size()]));

}
 

private CommonDropAdapterAssistant[] pyGetAssistantsBySelection(
        CommonDropAdapterDescriptor[] descriptors, IStructuredSelection aSelection) {

    Set assistants = new LinkedHashSet();

    for (int i = 0; i < descriptors.length; i++) {
        if (descriptors[i].areDragElementsSupported(aSelection)) {
            assistants.add(pyGetAssistant(descriptors[i]));
        }
    }

    return pySortAssistants((CommonDropAdapterAssistant[]) assistants
            .toArray(new CommonDropAdapterAssistant[assistants.size()]));
}