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 Jakarta Messaging 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 Jakarta 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 Jakarta Messaging provider fails to get the MessageListener
for one of the following
reasons:
setMessageListener(jakarta.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 Jakarta 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 Jakarta Messaging 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 Jakarta Messaging 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 Jakarta Messaging provider fails to receive the next message due to some internal error.Message receiveNoWait()
JMSConsumer
, or null if one is not availableJMSRuntimeException
- if the Jakarta Messaging 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 Jakarta Messaging 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 Jakarta Messaging 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 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 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.T
- The type of the message bodyc
- 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 Jakarta Messaging 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 Jakarta Messaging 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 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 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.T
- The message body typec
- 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
).timeout
- The maximum amount of time this method blocks. Zero means blocking indefinitely.JMSConsumer
, or null if the timeout expires or this
JMSConsumer
is concurrently closedMessageFormatRuntimeException
- ObjectMessage
and object deserialization fails.
JMSRuntimeException
- if the Jakarta Messaging 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 Jakarta Messaging 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 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 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.T
- The type of the message bodyc
- 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 Jakarta Messaging provider fails to receive the next message due to some internal errorCopyright 2004-2024 Solace Corporation. All rights reserved.