private T processInternal(ParametersWrapper parameters) throws Exception {
HandlerMethod candidate = this.findHandlerMethodForParameters(parameters);
Assert.notNull(candidate, "No candidate methods found for messages.");
Expression expression = candidate.getExpression();
Class<?> expectedType =
this.expectedType != null ? this.expectedType : candidate.method.getReturnType();
try {
@SuppressWarnings("unchecked")
T result = (T) this.evaluateExpression(expression, parameters, expectedType);
if (this.requiresReply) {
Assert.notNull(
result, "Expression evaluation result was null, but this processor requires a reply.");
}
return result;
} catch (Exception e) {
Throwable evaluationException = e;
if ((e instanceof EvaluationException || e instanceof MessageHandlingException)
&& e.getCause() != null) {
evaluationException = e.getCause();
}
if (evaluationException instanceof Exception) {
throw (Exception) evaluationException;
} else {
throw new IllegalStateException("Cannot process message", evaluationException);
}
}
}
/**
* Returns a map of the {@link HandlerMethod} objects to the corresponding message class.
*
* @param declaringClass the class that declares methods to scan
* @param filter the predicate that defines rules for subscriber scanning
* @return the map of message subscribers
* @throws DuplicateHandlerMethodException if there are more than one handler for the same message
* class are encountered
*/
private static Map<Class<? extends Message>, Method> scan(
Class<?> declaringClass, Predicate<Method> filter) {
final Map<Class<? extends Message>, Method> tempMap = Maps.newHashMap();
for (Method method : declaringClass.getDeclaredMethods()) {
if (filter.apply(method)) {
final Class<? extends Message> messageClass = HandlerMethod.getFirstParamType(method);
if (tempMap.containsKey(messageClass)) {
final Method alreadyPresent = tempMap.get(messageClass);
throw new DuplicateHandlerMethodException(
declaringClass, messageClass, alreadyPresent.getName(), method.getName());
}
tempMap.put(messageClass, method);
}
}
final ImmutableMap<Class<? extends Message>, Method> result = ImmutableMap.copyOf(tempMap);
return result;
}
