I am having a weird issue of not being able to cast a packet into a message. I get an error at this line: Message msg = (Message) arg0; It says
"Cannot cast from Packet to Message"
//Code
connection.connect();
connection.login(uN, pw);
PacketTypeFilter filter = new PacketTypeFilter(Message.class);
PacketCollector myCollector = connection.createPacketCollector(filter);
PacketListener myListener = new PacketListener(){
#Override
public void processPacket(Packet arg0) {
// TODO Auto-generated method stub
if(arg0 instanceof org.jivesoftware.smack.packet.Message){
Message msg = (Message) arg0;
}
}
};
connection.addPacketListener(myListener, filter);
I am going to guess that since you have Message fully qualified in the check for instanceof but not in the line with your cast, that the Message used in your cast is not the correct Message class.
Check your imports and see what Message you have there, it is probably not org.jivesoftware.smack.packet.Message.
Related
i am not sure my understanding to errorHandler and returnExceptions is right or not.
but here is my goal: i sent a message from App_A, use #RabbitListener to receive message in App_B.
according to the doc
https://docs.spring.io/spring-amqp/docs/2.1.3.BUILD-SNAPSHOT/reference/html/_reference.html#annotation-error-handling
i assume if APP_B has a business exception during process the message,through set errorHandler and returnExceptions in a right way on #RabbitListener can let the exception back to App_A.
do I understood correctly?
if i am rigth, how to use it in a right way?
with my code, i get nothing in APP_A .
here is my code in APP_B
errorHandler:
#Component(value = "errorHandler")
public class ErrorHandler implements RabbitListenerErrorHandler {
#Override
public Object handleError(Message arg0, org.springframework.messaging.Message<?> arg1,
ListenerExecutionFailedException arg2) throws ListenerExecutionFailedException {
throw new ListenerExecutionFailedException("msg", arg2, null);
}
}
RabbitListener:
#RabbitListener(
bindings = #QueueBinding(
value = #Queue(value = "MRO.updateBaseInfo.queue", durable = "true"),
exchange = #Exchange(name = "MRO_Exchange", type = ExchangeTypes.DIRECT, durable = "true"),
key = "baseInfoUpdate"
),
// errorHandler = "errorHandler",
returnExceptions = "true"
)
public void receiveLocationChangeMessage(String message){
BaseUpdateMessage newBaseInfo = JSON.parseObject(message, BaseUpdateMessage.class);
dao.upDateBaseInfo(newBaseInfo);
}
and code in APP_A
#Component
public class MessageSender {
#Autowired
private RabbitTemplate rabbitTemplate;
public void editBaseInfo(BaseUpdateMessage message)throws Exception {
//and i am not sure set RemoteInvocationAwareMessageConverterAdapter in this way is right
rabbitTemplate.setMessageConverter(new RemoteInvocationAwareMessageConverterAdapter());
rabbitTemplate.convertAndSend("MRO_Exchange", "baseInfoUpdate", JSON.toJSONString(message));
}
}
i am very confuse with three points:
1)do i have to use errorHandler and returnExceptions at the same time? i thought errorHandler is something like a postprocessor that let me custom exception.if i don't need a custom exception can i just set returnExceptions with out errorHandler ?
2)should the method annotated with #RabbitListener return something or void is just fine?
3)in the sender side(my situation is APP_A), does have any specific config to catch the exception?
my workspace environment:
Spring boot 2.1.0
rabbitMQ server 3.7.8 on docker
1) No, you don't need en error handler, unless you want to enhance the exception.
2) If the method returns void; the sender will end up waiting for timeout for a reply that will never arrive, just in case an exception might be thrown; that is probably not a good use of resources. It's better to always send a reply, to free up the publisher side.
3) Just the RemoteInvocationAwareMessageConverterAdapter.
Here's an example:
#SpringBootApplication
public class So53846303Application {
public static void main(String[] args) {
SpringApplication.run(So53846303Application.class, args);
}
#RabbitListener(queues = "foo", returnExceptions = "true")
public String listen(String in) {
throw new RuntimeException("foo");
}
#Bean
public ApplicationRunner runner(RabbitTemplate template) {
template.setMessageConverter(new RemoteInvocationAwareMessageConverterAdapter());
return args -> {
try {
template.convertSendAndReceive("foo", "bar");
}
catch (Exception e) {
e.printStackTrace();
}
};
}
}
and
org.springframework.amqp.AmqpRemoteException: java.lang.RuntimeException: foo
at org.springframework.amqp.support.converter.RemoteInvocationAwareMessageConverterAdapter.fromMessage(RemoteInvocationAwareMessageConverterAdapter.java:74)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1500)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1433)
at org.springframework.amqp.rabbit.core.RabbitTemplate.convertSendAndReceive(RabbitTemplate.java:1425)
at com.example.So53846303Application.lambda$0(So53846303Application.java:28)
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:804)
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:794)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:324)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
at com.example.So53846303Application.main(So53846303Application.java:15)
Caused by: java.lang.RuntimeException: foo
at com.example.So53846303Application.listen(So53846303Application.java:20)
As you can see, there is a local org.springframework.amqp.AmqpRemoteException with the cause being the actual exception thrown on the remote server.
As per doc, defaultRequeueRejected's default value is true, but looking at code it seems its false. I am not sure if I am missing anything or we have to change that in SimpleRabbitListenerContainerFactory.java
EDIT
Sample code, after putting message in test queue, I expect it to stay in queue since its failing but it is throwing it out. I want message to be retried so I configured that in container factory if it fails after retry I want it to be back in queue. I am sure I am missing understanding here.
#SpringBootApplication
public class MsgRequeExampleApplication {
public static void main(String[] args) {
SpringApplication.run(MsgRequeExampleApplication.class, args);
}
#Bean(name = "myContainerFactory")
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory(ConnectionFactory connectionFactory) {
SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
factory.setConnectionFactory(connectionFactory);
factory.setMessageConverter(new Jackson2JsonMessageConverter());
factory.setMissingQueuesFatal(false);
FixedBackOffPolicy backOffPolicy = new FixedBackOffPolicy();
backOffPolicy.setBackOffPeriod(500);
factory.setAdviceChain(new Advice[] { org.springframework.amqp.rabbit.config.RetryInterceptorBuilder.stateless()
.maxAttempts(2).backOffPolicy(backOffPolicy).build() });
return factory;
}
#RabbitListener(queues = "test", containerFactory = "myContainerFactory")
public void processAdvisory(Message message) throws MyBusinessException {
try{
//Simulating exception while processing message
String nullString=null;
nullString.length();
}catch(Exception ex){
throw new MyBusinessException(ex.getMessage());
}
}
public class MyBusinessException extends Exception {
public MyBusinessException(String msg) {
super(msg);
}
}
}
There is a good description in the SimpleMessageListenerContainer JavaDocs:
/**
* Set the default behavior when a message is rejected, for example because the listener
* threw an exception. When true, messages will be requeued, when false, they will not. For
* versions of Rabbit that support dead-lettering, the message must not be requeued in order
* to be sent to the dead letter exchange. Setting to false causes all rejections to not
* be requeued. When true, the default can be overridden by the listener throwing an
* {#link AmqpRejectAndDontRequeueException}. Default true.
* #param defaultRequeueRejected true to reject by default.
*/
public void setDefaultRequeueRejected(boolean defaultRequeueRejected) {
this.defaultRequeueRejected = defaultRequeueRejected;
}
Does it make sense to you?
UPDATE
To requeue after retry exhausting you need to configure some custom MessageRecoverer on the RetryInterceptorBuilder with the code like:
.recoverer((message, cause) -> {
ReflectionUtils.rethrowRuntimeException(cause);
})
This way the exception will be thrown to the listener container and according its defaultRequeueRejected the message will be requeued or not.
I need to add header to a STOMP message currently it is working as below but i am recreating the message , is it possible to just add native header without having to recreate the message for performance .
public class MyChannelInterceptor extends ChannelInterceptorAdapter {
#Override
public Message<?> preSend(Message<?> message, MessageChannel channel) {
StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
StompCommand command = accessor.getCommand();
if(command != null) {
log.debug("Receiving msg {} from {}",command,accessor.getUser().getName());
if(command == StompCommand.SEND) {
log.debug("Adding expires header to msg {} from {}",command,accessor.getUser().getName());
String ttlString = accessor.getFirstNativeHeader("ttl");
long ttl = 30000;
try {
ttl = Long.parseLong(ttlString);
}
catch(Exception ex) {
log.error("TTL header received but not in correct format {}",ttlString);
}
accessor.addNativeHeader("expires", Long.toString(System.currentTimeMillis() + ttl));
return MessageBuilder.createMessage(message.getPayload(), accessor.getMessageHeaders());
}
}
return message;
}
}
This is what i was looking for
StompHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, StompHeaderAccessor.class);
The above code will get the actual StompHeaderAccessor of the message so if you manipulate the native headers they are directly reflected on the message while
StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
will get a clone of the headers and you have to create a new message with the new cloned headers
full fixed code below
#Override
public Message<?> preSend(Message<?> message, MessageChannel channel) {
StompHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, StompHeaderAccessor.class);
// StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
if(accessor != null) {
StompCommand command = accessor.getCommand();
if(command != null) {
log.debug("Receiving msg {} from {}",command,accessor.getUser().getName());
if(command == StompCommand.SEND) {
log.debug("Adding expires header to msg {} from {}",command,accessor.getUser().getName());
String ttlString = accessor.getFirstNativeHeader("ttl");
long ttl = 30000;
if(ttlString != null) {
try {
ttl = Long.parseLong(ttlString);
}
catch(Exception ex) {
log.error("TTL header received but not in correct format {}",ttlString);
}
}
accessor.addNativeHeader("expires", Long.toString(System.currentTimeMillis() + ttl));
// I don't need any more to create a new message
//return MessageBuilder.createMessage(message.getPayload(), accessor.getMessageHeaders());
}
}
}
return message;
}
Since addNativeHeader succeeds, that indicates the message is still mutable - see addNativeHeader().
In any case, since the NATIVE_HEADERS message header is a MultiValueMap-valued header, you can update the header contents in-place.
Hence, there is no need to create a new message.
You would have to create a new message if you add a new header to the message itself (rather than updating the mutable contents of an existing header).
EDIT
I just ran a test; as long as the message is still mutable, you can change it...
#Test
public void test() {
Map<String, Object> map = new HashMap<String, Object>();
MutableMessageHeaders headers = new MutableMessageHeaders(map);
Message<String> message = MessageBuilder.createMessage("foo", headers);
StompHeaderAccessor accessor = StompHeaderAccessor.wrap(message);
accessor.addNativeHeader("foo", "bar");
System.out.println(message.getHeaders().get(NativeMessageHeaderAccessor.NATIVE_HEADERS));
accessor.setImmutable();
try {
accessor.addNativeHeader("baz", "qux");
fail("expected IllegalStateException");
}
catch (IllegalStateException e) {
}
}
That said, are you experiencing a performance problem or is this just a perceived issue. Message creation is not expensive.
I have the followinf scenario:
I have field with DoubleRangeValidator with error message specified
field.addValidator(new DoubleRangeValidator("Salary must be a numeric value.",0d,1000000d));
Under SAVE button I call BeanFieldGroup.commit() which raises exception on non numeric value in such field
To show errors I'm using ErrorUtils class mentioned here
Display error messages directly in Vaadin 7
.. which simply calls component.getErrorMessage() for all fields / components and gather all error messages. But the field with DoubleRange validator returns null for getErrorMessage() so no error message is available here. The same apply for other validators. So my question is how can I show validator error messages when validation error occures during the commit() ?
I've tried to reproduce your error with the ErrorUtils class you mentioned but the getErrorMessage method did not returned null. Maybe something is wrong with how you create your BeanFieldGroup and/or Field. Here's my code:
#Override
protected void init(VaadinRequest request) {
BeanFieldGroup<MyBean> bfg = new BeanFieldGroup<>(MyBean.class);
bfg.setItemDataSource(new MyBean());
Field<?> salaryField = bfg.buildAndBind("salary");
salaryField.addValidator(new DoubleRangeValidator("Salary must be a numeric value.", 0d, 1000000d));
Button commit = new Button("Save", e -> {
try {
bfg.commit();
}
catch (CommitException ce) {
ErrorUtils.showComponentErrors(bfg.getFields());
}
});
VerticalLayout hLayout = new VerticalLayout(salaryField, commit);
setContent(hLayout);
}
public class MyBean implements Serializable {
private static final long serialVersionUID = 1L;
private double salary;
public MyBean() {}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
}
Hi friends i am trying to read incoming sms but getting warning like this . Invocation of questionable method: java.lang.String.(String) found in: mypackage.MyApp$ListeningThread.run()
Here is my code is
public class MyApp extends UiApplication {
//private ListeningThread listener;
public static void main(String[] args) {
MyApp theApp = new MyApp();
theApp.enterEventDispatcher();
}
public MyApp() {
invokeAndWait(new Runnable() {
public void run() {
ListeningThread listener = new ListeningThread();
listener.start();
}
});
pushScreen(new MyScreen());
}
private static class ListeningThread extends Thread {
private boolean _stop = false;
private DatagramConnection _dc;
public synchronized void stop() {
_stop = true;
try {
_dc.close(); // Close the connection so the thread returns.
} catch (IOException e) {
System.err.println(e.toString());
}
}
public void run() {
try {
_dc = (DatagramConnection) Connector.open("sms://");
for (;;) {
if (_stop) {
return;
}
Datagram d = _dc.newDatagram(_dc.getMaximumLength());
_dc.receive(d);
String address = new String(d.getAddress());
String msg = new String(d.getData());
if(msg.startsWith("START")){
Dialog.alert("hello");
}
System.out.println("Message received: " + msg);
System.out.println("From: " + address);
System.exit(0);
}
} catch (IOException e) {
System.err.println(e.toString());
}
}
}
}
Please correct me where i am wrong.Is possible give me some code to read incoming sms content in blackberry.
A few points about your code:
That invokeAndWait call to launch a thread makes no sense. It doesn't harm, but is kind of waste. Use that method only to perform UI related operations.
You should try using "sms://:0" as param for Connector.open. According to the docs, a parameter with the form {protocol}://[{host}]:[{port}] will open the connection in client mode (which makes sense, since you are on the receiving part), whereas not including the host part will open it in server mode.
Finally, if you can't get it working, you could use instead the third method specified in this tutorial, which you probably have already read.
The error you quoted is complaining about the use of the String constructor that takes a string argument. Since strings are immutable in Java-ME, this is just a waste. You can use the argument string directly:
Invocation of questionable method: java.lang.String.(String) found in: mypackage.MyApp$ListeningThread.run()
//String address = new String(d.getAddress());
String address = d.getAddress();
// getData() returns a byte[], so this is a different constructor
// However, this leaves the character encoding unspecified, so it
// will default to cp1252, which may not be what you want
String msg = new String(d.getData());