public interface JMSConsumer
extends java.lang.AutoCloseable
JMSConsumer
object to receive messages from a queue or topic. A
JMSConsumer
object may be created either created by passing a
Queue
or Topic
object to one of the createConsumer
methods on a JMSContext
. or by passing a Topic
object to one
of the createSharedConsumer
or createDurableConsumer
methods
on a JMSContext
.
A JMSConsumer
can be created with a message selector. A message
selector allows the client to restrict the messages delivered to the
JMSConsumer
to those that match the selector.
A client may either synchronously receive a JMSConsumer
's messages or
have the JMSConsumer
asynchronously deliver them as they arrive.
For synchronous receipt, a client can request the next message from a
JMSConsumer
using one of its receive
methods. There are
several variations of receive
that allow a client to poll or wait for
the next message.
For asynchronous delivery, a client can register a MessageListener
object with a JMSConsumer
. As messages arrive at the
JMSConsumer
, it delivers them by calling the MessageListener
's onMessage
method.
It is a client programming error for a MessageListener
to throw an
exception.
JMSContext
Modifier and Type | Method and Description |
---|---|
void |
close()
Closes the
JMSConsumer . |
MessageListener |
getMessageListener()
Gets the
JMSConsumer 's MessageListener . |
java.lang.String |
getMessageSelector()
Gets this
JMSConsumer 's message selector expression. |
Message |
receive()
Receives the next message produced for this
JMSConsumer . |
Message |
receive(long timeout)
Receives the next message that arrives within the specified
timeout interval.
|
<T> T |
receiveBody(java.lang.Class<T> c)
Receives the next message produced for this
JMSConsumer and
returns its body as an object of the specified type. |
<T> T |
receiveBody(java.lang.Class<T> c,
long timeout)
Receives the next message produced for this
JMSConsumer
that arrives within the specified timeout period and
returns its body as an object of the specified type. |
<T> T |
receiveBodyNoWait(java.lang.Class<T> c)
Receives the next message produced for this
JMSConsumer
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 the
JMSConsumer 's MessageListener . |
java.lang.String getMessageSelector()
JMSConsumer
's message selector expression.JMSConsumer
's message selector, or null if no
message selector exists for the JMSConsumer
(that is, if
the message selector was not set or was set to null or the
empty string)JMSRuntimeException
- if the JMS provider fails to get the message
selector due to some internal error.MessageListener getMessageListener() throws JMSRuntimeException
JMSConsumer
's MessageListener
.
This method must not be used in a Java EE web or EJB application.
Doing so may cause a JMSRuntimeException
to be thrown though this is not guaranteed.
JMSConsumer
's MessageListener
, or null if one was not setJMSRuntimeException
- if the JMS provider fails to get the MessageListener
for one of the following reasons:
setMessageListener(javax.jms.MessageListener)
void setMessageListener(MessageListener listener) throws JMSRuntimeException
JMSConsumer
's MessageListener
.
Setting the MessageListener
to null is the equivalent of
unsetting the MessageListener
for the JMSConsumer
.
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 Java EE web or EJB application.
Doing so may cause a JMSRuntimeException
to be thrown though this is not guaranteed.
listener
- the listener to which the messages are to be
deliveredJMSRuntimeException
- if the JMS provider fails to set the JMSConsumer
's MessageListener
for one of the following reasons:
getMessageListener()
Message receive()
JMSConsumer
.
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.
JMSConsumer
, or
null if this JMSConsumer
is concurrently closedJMSRuntimeException
- if the JMS provider fails to receive the next
message due to some internal error.Message receive(long timeout)
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.
timeout
- the timeout value (in milliseconds)JMSConsumer
, or
null if the timeout expires or this JMSConsumer
is concurrently
closedJMSRuntimeException
- if the JMS provider fails to receive the next
message due to some internal error.Message receiveNoWait()
JMSConsumer
, or
null if one is not availableJMSRuntimeException
- if the JMS provider fails to receive the next
message due to some internal error.void close()
JMSConsumer
.
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 blocked receive
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 the
onMessage
method will be allowed to complete normally.
This method is the only JMSConsumer
method that can be called
concurrently.
close
in interface java.lang.AutoCloseable
JMSRuntimeException
- if the JMS provider fails to close the consumer due to
some internal error.<T> T receiveBody(java.lang.Class<T> c)
JMSConsumer
and
returns its body as an object of the specified type.
This method may be used to receive any type of message except
for StreamMessage
and Message
, 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 a MessageFormatRuntimeException
is thrown.
This method does not give access to the message headers or properties
(such as the JMSRedelivered
message header field or the
JMSXDeliveryCount
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
or DUPS_OK_ACKNOWLEDGE
: The JMS
provider will behave as if the unsuccessful call to receiveBody
had
not occurred. The message will be delivered again before any subsequent
messages.
This is not considered to be redelivery and does not cause the
JMSRedelivered
message header field to be set or the
JMSXDeliveryCount
message property to be incremented.
CLIENT_ACKNOWLEDGE
: The JMS 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 with a session mode of
CLIENT_ACKNOWLEDGE
, the message will not be acknowledged until
acknowledge
is called on the JMSContext
. If an
application wishes to have the failed message redelivered, it must call
recover
on the JMSContext
. The redelivered message's
JMSRedelivered
message header field will be set and its
JMSXDeliveryCount
message property will be incremented.
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's JMSRedelivered
message header field will be
set and its JMSXDeliveryCount
message property will be
incremented.
c
- The type to which the body of the next message should be
assigned.TextMessage
then this should be set to String.class
or another
class to which a String
is assignable.ObjectMessage
then this should be set to java.io.Serializable.class
or another class to which the body is assignable. MapMessage
then this should be set to java.util.Map.class
(or java.lang.Object.class
).BytesMessage
then this should be set to byte[].class
(or java.lang.Object.class
).JMSConsumer
, or null if this JMSConsumer
is
concurrently closedMessageFormatRuntimeException
- ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the JMS provider fails to receive the next message due to
some internal error<T> T receiveBody(java.lang.Class<T> c, long timeout)
JMSConsumer
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
for StreamMessage
and Message
, 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 a MessageFormatRuntimeException
is thrown.
This method does not give access to the message headers or properties
(such as the JMSRedelivered
message header field or the
JMSXDeliveryCount
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
or DUPS_OK_ACKNOWLEDGE
: The JMS
provider will behave as if the unsuccessful call to receiveBody
had
not occurred. The message will be delivered again before any subsequent
messages.
This is not considered to be redelivery and does not cause the
JMSRedelivered
message header field to be set or the
JMSXDeliveryCount
message property to be incremented.
CLIENT_ACKNOWLEDGE
: The JMS 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 with a session mode of
CLIENT_ACKNOWLEDGE
, the message will not be acknowledged until
acknowledge
is called on the JMSContext
. If an
application wishes to have the failed message redelivered, it must call
recover
on the JMSContext
. The redelivered message's
JMSRedelivered
message header field will be set and its
JMSXDeliveryCount
message property will be incremented.
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's JMSRedelivered
message header field will be
set and its JMSXDeliveryCount
message property will be
incremented.
c
- The type to which the body of the next message should be
assigned.TextMessage
then this should be set to String.class
or another
class to which a String
is assignable.ObjectMessage
then this should be set to java.io.Serializable.class
or another class to which the body is assignable. MapMessage
then this should be set to java.util.Map.class
(or java.lang.Object.class
).BytesMessage
then this should be set to byte[].class
(or java.lang.Object.class
).JMSConsumer
,
or null if the timeout expires or this JMSConsumer
is concurrently closedMessageFormatRuntimeException
- ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the JMS provider fails to receive the next message due
to some internal error<T> T receiveBodyNoWait(java.lang.Class<T> c)
JMSConsumer
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
for StreamMessage
and Message
, 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 a MessageFormatRuntimeException
is thrown.
This method does not give access to the message headers or properties
(such as the JMSRedelivered
message header field or the
JMSXDeliveryCount
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
or DUPS_OK_ACKNOWLEDGE
: The JMS
provider will behave as if the unsuccessful call to receiveBodyNoWait
had
not occurred. The message will be delivered again before any subsequent
messages.
This is not considered to be redelivery and does not cause the
JMSRedelivered
message header field to be set or the
JMSXDeliveryCount
message property to be incremented.
CLIENT_ACKNOWLEDGE
: The JMS 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 with a session mode of
CLIENT_ACKNOWLEDGE
, the message will not be acknowledged until
acknowledge
is called on the JMSContext
. If an
application wishes to have the failed message redelivered, it must call
recover
on the JMSContext
. The redelivered message's
JMSRedelivered
message header field will be set and its
JMSXDeliveryCount
message property will be incremented.
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's JMSRedelivered
message header field will be
set and its JMSXDeliveryCount
message property will be
incremented.
c
- The type to which the body of the next message should be
assigned.TextMessage
then this should be set to String.class
or another
class to which a String
is assignable.ObjectMessage
then this should be set to java.io.Serializable.class
or another class to which the body is assignable. MapMessage
then this should be set to java.util.Map.class
(or java.lang.Object.class
).BytesMessage
then this should be set to byte[].class
(or java.lang.Object.class
).JMSConsumer
,
or null if one is not immediately available or this JMSConsumer
is concurrently closedMessageFormatRuntimeException
- ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the JMS provider fails to receive the next message due
to some internal error