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- All Superinterfaces:
AutoCloseable
public interface JMSConsumer extends AutoCloseable
A client using the simplified Jakarta Messaging API introduced for Jakarta Messaging 2.0 uses aJMSConsumer
object to receive messages from a queue or topic. AJMSConsumer
object may be created either created by passing aQueue
orTopic
object to one of thecreateConsumer
methods on aJMSContext
. or by passing aTopic
object to one of thecreateSharedConsumer
orcreateDurableConsumer
methods on aJMSContext
.A
JMSConsumer
can be created with a message selector. A message selector allows the client to restrict the messages delivered to theJMSConsumer
to those that match the selector.A client may either synchronously receive a
JMSConsumer
's messages or have theJMSConsumer
asynchronously deliver them as they arrive.For synchronous receipt, a client can request the next message from a
JMSConsumer
using one of itsreceive
methods. There are several variations ofreceive
that allow a client to poll or wait for the next message.For asynchronous delivery, a client can register a
MessageListener
object with aJMSConsumer
. As messages arrive at theJMSConsumer
, it delivers them by calling theMessageListener
'sonMessage
method.It is a client programming error for a
MessageListener
to throw an exception.- Since:
- JMS 2.0
- Version:
- Jakarta Messaging 2.0
- See Also:
JMSContext
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description void
close()
Closes theJMSConsumer
.MessageListener
getMessageListener()
Gets theJMSConsumer
'sMessageListener
.String
getMessageSelector()
Gets thisJMSConsumer
's message selector expression.Message
receive()
Receives the next message produced for thisJMSConsumer
.Message
receive(long timeout)
Receives the next message that arrives within the specified timeout interval.<T> T
receiveBody(Class<T> c)
Receives the next message produced for thisJMSConsumer
and returns its body as an object of the specified type.<T> T
receiveBody(Class<T> c, long timeout)
Receives the next message produced for thisJMSConsumer
that arrives within the specified timeout period and returns its body as an object of the specified type.<T> T
receiveBodyNoWait(Class<T> c)
Receives the next message produced for thisJMSConsumer
if one is immediately available and returns its body as an object of the specified type.Message
receiveNoWait()
Receives the next message if one is immediately available.void
setMessageListener(MessageListener listener)
Sets theJMSConsumer
'sMessageListener
.
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Method Detail
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getMessageSelector
String getMessageSelector()
Gets thisJMSConsumer
's message selector expression.- Returns:
- this
JMSConsumer
's message selector, or null if no message selector exists for theJMSConsumer
(that is, if the message selector was not set or was set to null or the empty string) - Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to get the message selector due to some internal error.
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getMessageListener
MessageListener getMessageListener() throws JMSRuntimeException
Gets theJMSConsumer
'sMessageListener
.This method must not be used in a Jakarta EE web or EJB application. Doing so may cause a
JMSRuntimeException
to be thrown though this is not guaranteed.- Returns:
- the
JMSConsumer
'sMessageListener
, or null if one was not set - Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to get theMessageListener
for one of the following reasons:- an internal error has occurred or
- this method has been called in a Jakarta EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)
- See Also:
setMessageListener(jakarta.jms.MessageListener)
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setMessageListener
void setMessageListener(MessageListener listener) throws JMSRuntimeException
Sets theJMSConsumer
'sMessageListener
.Setting the
MessageListener
to null is the equivalent of unsetting theMessageListener
for theJMSConsumer
.The effect of calling this method while messages are being consumed by an existing listener or the
JMSConsumer
is being used to consume messages synchronously is undefined.This method must not be used in a Jakarta EE web or EJB application. Doing so may cause a
JMSRuntimeException
to be thrown though this is not guaranteed.- Parameters:
listener
- the listener to which the messages are to be delivered- Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to set theJMSConsumer
'sMessageListener
for one of the following reasons:- an internal error has occurred or
- this method has been called in a Jakarta EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)
- See Also:
getMessageListener()
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receive
Message receive()
Receives the next message produced for thisJMSConsumer
.This call blocks indefinitely until a message is produced or until this
JMSConsumer
is closed.If this
receive
is done within a transaction, the JMSConsumer retains the message until the transaction commits.- Returns:
- the next message produced for this
JMSConsumer
, or null if thisJMSConsumer
is concurrently closed - Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error.
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receive
Message receive(long timeout)
Receives the next message that arrives within the specified timeout interval.This call blocks until a message arrives, the timeout expires, or this
JMSConsumer
is closed. Atimeout
of zero never expires, and the call blocks indefinitely.- Parameters:
timeout
- the timeout value (in milliseconds)- Returns:
- the next message produced for this
JMSConsumer
, or null if the timeout expires or thisJMSConsumer
is concurrently closed - Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error.
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receiveNoWait
Message receiveNoWait()
Receives the next message if one is immediately available.- Returns:
- the next message produced for this
JMSConsumer
, or null if one is not available - Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error.
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close
void close()
Closes theJMSConsumer
.Since a provider may allocate some resources on behalf of a
JMSConsumer
outside the Java virtual machine, clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely enough.This call will block until a
receive
call in progress on this consumer has completed. A blockedreceive
call returns null when this consumer is closed.If this method is called whilst a message listener is in progress in another thread then it will block until the message listener has completed.
This method may be called from a message listener's
onMessage
method on its own consumer. After this method returns theonMessage
method will be allowed to complete normally.This method is the only
JMSConsumer
method that can be called concurrently.- Specified by:
close
in interfaceAutoCloseable
- Throws:
JMSRuntimeException
- if the Jakarta Messaging provider fails to close the consumer due to some internal error.
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receiveBody
<T> T receiveBody(Class<T> c)
Receives the next message produced for thisJMSConsumer
and returns its body as an object of the specified type. This method may be used to receive any type of message except forStreamMessage
andMessage
, so long as the message has a body which is capable of being assigned to the specified type. This means that the specified class or interface must either be the same as, or a superclass or superinterface of, the class of the message body. If the message is not one of the supported types, or its body cannot be assigned to the specified type, or it has no body, then aMessageFormatRuntimeException
is thrown.This method does not give access to the message headers or properties (such as the
JMSRedelivered
message header field or theJMSXDeliveryCount
message property) and should only be used if the application has no need to access them.This call blocks indefinitely until a message is produced or until this
JMSConsumer
is closed.If this method is called within a transaction, the
JMSConsumer
retains the message until the transaction commits.The result of this method throwing a
MessageFormatRuntimeException
depends on the session mode:AUTO_ACKNOWLEDGE
orDUPS_OK_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the unsuccessful call toreceiveBody
had not occurred. The message will be delivered again before any subsequent messages. This is not considered to be redelivery and does not cause theJMSRedelivered
message header field to be set or theJMSXDeliveryCount
message property to be incremented.CLIENT_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the call toreceiveBody
had been successful and will not deliver the message again. As with any message that is delivered with a session mode ofCLIENT_ACKNOWLEDGE
, the message will not be acknowledged untilacknowledge
is called on theJMSContext
. If an application wishes to have the failed message redelivered, it must callrecover
on theJMSContext
. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.- Transacted session: The Jakarta Messaging provider will behave as if the call to
receiveBody
had been successful and will not deliver the message again. As with any message that is delivered in a transacted session, the transaction will remain uncommitted until the transaction is committed or rolled back by the application. If an application wishes to have the failed message redelivered, it must roll back the transaction. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.
- Type Parameters:
T
- The type of the message body- Parameters:
c
- The type to which the body of the next message should be assigned.
If the next message is expected to be aTextMessage
then this should be set toString.class
or another class to which aString
is assignable.
If the next message is expected to be aObjectMessage
then this should be set tojava.io.Serializable.class
or another class to which the body is assignable.
If the next message is expected to be aMapMessage
then this should be set tojava.util.Map.class
(orjava.lang.Object.class
).
If the next message is expected to be aBytesMessage
then this should be set tobyte[].class
(orjava.lang.Object.class
).- Returns:
- the body of the next message produced for this
JMSConsumer
, or null if thisJMSConsumer
is concurrently closed - Throws:
MessageFormatRuntimeException
-- if the message is not one of the supported types listed above
- if the message body cannot be assigned to the specified type
- if the message has no body
- if the message is an
ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error
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receiveBody
<T> T receiveBody(Class<T> c, long timeout)
Receives the next message produced for thisJMSConsumer
that arrives within the specified timeout period and returns its body as an object of the specified type. This method may be used to receive any type of message except forStreamMessage
andMessage
, so long as the message has a body which is capable of being assigned to the specified type. This means that the specified class or interface must either be the same as, or a superclass or superinterface of, the class of the message body. If the message is not one of the supported types, or its body cannot be assigned to the specified type, or it has no body, then aMessageFormatRuntimeException
is thrown.This method does not give access to the message headers or properties (such as the
JMSRedelivered
message header field or theJMSXDeliveryCount
message property) and should only be used if the application has no need to access them.This call blocks until a message arrives, the timeout expires, or this
JMSConsumer
is closed. A timeout of zero never expires, and the call blocks indefinitely.If this method is called within a transaction, the
JMSConsumer
retains the message until the transaction commits.The result of this method throwing a
MessageFormatRuntimeException
depends on the session mode:AUTO_ACKNOWLEDGE
orDUPS_OK_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the unsuccessful call toreceiveBody
had not occurred. The message will be delivered again before any subsequent messages. This is not considered to be redelivery and does not cause theJMSRedelivered
message header field to be set or theJMSXDeliveryCount
message property to be incremented.CLIENT_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the call toreceiveBody
had been successful and will not deliver the message again. As with any message that is delivered with a session mode ofCLIENT_ACKNOWLEDGE
, the message will not be acknowledged untilacknowledge
is called on theJMSContext
. If an application wishes to have the failed message redelivered, it must callrecover
on theJMSContext
. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.- Transacted session: The Jakarta Messaging provider will behave as if the call to
receiveBody
had been successful and will not deliver the message again. As with any message that is delivered in a transacted session, the transaction will remain uncommitted until the transaction is committed or rolled back by the application. If an application wishes to have the failed message redelivered, it must roll back the transaction. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.
- Type Parameters:
T
- The message body type- Parameters:
c
- The type to which the body of the next message should be assigned.
If the next message is expected to be aTextMessage
then this should be set toString.class
or another class to which aString
is assignable.
If the next message is expected to be aObjectMessage
then this should be set tojava.io.Serializable.class
or another class to which the body is assignable.
If the next message is expected to be aMapMessage
then this should be set tojava.util.Map.class
(orjava.lang.Object.class
).
If the next message is expected to be aBytesMessage
then this should be set tobyte[].class
(orjava.lang.Object.class
).timeout
- The maximum amount of time this method blocks. Zero means blocking indefinitely.- Returns:
- the body of the next message produced for this
JMSConsumer
, or null if the timeout expires or thisJMSConsumer
is concurrently closed - Throws:
MessageFormatRuntimeException
-- if the message is not one of the supported types listed above
- if the message body cannot be assigned to the specified type
- if the message has no body
- if the message is an
ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error
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receiveBodyNoWait
<T> T receiveBodyNoWait(Class<T> c)
Receives the next message produced for thisJMSConsumer
if one is immediately available and returns its body as an object of the specified type. This method may be used to receive any type of message except forStreamMessage
andMessage
, so long as the message has a body which is capable of being assigned to the specified type. This means that the specified class or interface must either be the same as, or a superclass or superinterface of, the class of the message body. If the message is not one of the supported types, or its body cannot be assigned to the specified type, or it has no body, then aMessageFormatRuntimeException
is thrown.This method does not give access to the message headers or properties (such as the
JMSRedelivered
message header field or theJMSXDeliveryCount
message property) and should only be used if the application has no need to access them.If a message is not immediately available null is returned.
If this method is called within a transaction, the
JMSConsumer
retains the message until the transaction commits.The result of this method throwing a
MessageFormatRuntimeException
depends on the session mode:AUTO_ACKNOWLEDGE
orDUPS_OK_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the unsuccessful call toreceiveBodyNoWait
had not occurred. The message will be delivered again before any subsequent messages. This is not considered to be redelivery and does not cause theJMSRedelivered
message header field to be set or theJMSXDeliveryCount
message property to be incremented.CLIENT_ACKNOWLEDGE
: The Jakarta Messaging provider will behave as if the call toreceiveBodyNoWait
had been successful and will not deliver the message again. As with any message that is delivered with a session mode ofCLIENT_ACKNOWLEDGE
, the message will not be acknowledged untilacknowledge
is called on theJMSContext
. If an application wishes to have the failed message redelivered, it must callrecover
on theJMSContext
. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.- Transacted session: The Jakarta Messaging provider will behave as if the call to
receiveBodyNoWait
had been successful and will not deliver the message again. As with any message that is delivered in a transacted session, the transaction will remain uncommitted until the transaction is committed or rolled back by the application. If an application wishes to have the failed message redelivered, it must roll back the transaction. The redelivered message'sJMSRedelivered
message header field will be set and itsJMSXDeliveryCount
message property will be incremented.
- Type Parameters:
T
- The type of the message body- Parameters:
c
- The type to which the body of the next message should be assigned.
If the next message is expected to be aTextMessage
then this should be set toString.class
or another class to which aString
is assignable.
If the next message is expected to be aObjectMessage
then this should be set tojava.io.Serializable.class
or another class to which the body is assignable.
If the next message is expected to be aMapMessage
then this should be set tojava.util.Map.class
(orjava.lang.Object.class
).
If the next message is expected to be aBytesMessage
then this should be set tobyte[].class
(orjava.lang.Object.class
).- Returns:
- the body of the next message produced for this
JMSConsumer
, or null if one is not immediately available or thisJMSConsumer
is concurrently closed - Throws:
MessageFormatRuntimeException
-- if the message is not one of the supported types listed above
- if the message body cannot be assigned to the specified type
- if the message has no body
- if the message is an
ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the Jakarta Messaging provider fails to receive the next message due to some internal error
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