JMSConsumer (JMS API 2.0-b07 API)

All Superinterfaces:

AutoCloseable
```
public interface JMSConsumer
extends AutoCloseable
```
A client using the simplified JMS API introduced for JMS 2.0 uses a 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.

Version:

2.0

See Also:
JMSContext

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Closes the `JMSConsumer`.
`MessageListener`	`getMessageListener()` Gets the `JMSConsumer`'s `MessageListener`.
`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.
`Message`	`receiveNoWait()` Receives the next message if one is immediately available.
`<T> T`	`receivePayload(Class<T> c)` Receives the next message produced for this `JMSConsumer` and returns its payload, which must be of the specified type
`<T> T`	`receivePayload(Class<T> c, long timeout)` Receives the next message produced for this `JMSConsumer` that arrives within the specified timeout period, and returns its payload, which must be of the specified type
`<T> T`	`receivePayloadNoWait(Class<T> c)` Receives the next message produced for this `JMSConsumer` if one is immediately available and returns its payload, which must be of the specified type.
`void`	`setMessageListener(MessageListener listener)` Sets the `JMSConsumer`'s `MessageListener`.

- Method Detail
  - getMessageSelector
```
String getMessageSelector()
```
    Gets this JMSConsumer's message selector expression.
    
    Returns:
    this 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)
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to get the message selector due to some internal error.
  - getMessageListener
```
MessageListener getMessageListener()
                                   throws JMSRuntimeException
```
    Gets the 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.
    Returns:
    the JMSConsumer's MessageListener, or null if one was not set
    
    Throws:
    JMSRuntimeException - if the JMS provider fails to get the MessageListener for one of the following reasons:
    
    an internal error has occurred or
    this method has been called in a Java EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)
    See Also:
    setMessageListener(javax.jms.MessageListener)
  - setMessageListener
```
void setMessageListener(MessageListener listener)
                        throws JMSRuntimeException
```
    Sets the 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.
    Parameters:
    listener - the listener to which the messages are to be delivered
    
    Throws:
    JMSRuntimeException - if the JMS provider fails to set the JMSConsumer's MessageListener for one of the following reasons:
    
    an internal error has occurred or
    this method has been called in a Java EE web or EJB application (though it is not guaranteed that an exception is thrown in this case)
    See Also:
    getMessageListener()
  - receive
```
Message receive()
```
    Receives the next message produced for this 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.
    
    Returns:
    the next message produced for this JMSConsumer, or null if this JMSConsumer is concurrently closed
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to receive the next message due to some internal error.
  - 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. A timeout 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 this JMSConsumer is concurrently closed
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to receive the next message due to some internal error.
  - 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 JMS provider fails to receive the next message due to some internal error.
  - close
```
void close()
```
    Closes the 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 blocks until a receive in progress has completed. A blocked message consumer receive call returns null when this JMSConsumer is closed.
    
    Specified by:
    
    close in interface AutoCloseable
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to close the JMSConsumer due to some internal error.
  - receivePayload
```
<T> T receivePayload(Class<T> c)
```
    Receives the next message produced for this JMSConsumer and returns its payload, which must be of the specified type
    This call blocks indefinitely until a message is produced or until this JMSConsumer is closed.
    If receivePayload is called within a transaction, the JMSConsumer retains the message until the transaction commits.
    
    Parameters:
    c - The class of the payload of the next message.
    If the next message is expected to be a TextMessage then this should be set to String.class.
    If the next message is expected to be a ObjectMessage then this should be set to java.io.Serializable.class.
    If the next message is expected to be a MapMessage then this should be set to java.util.Map.class.
    If the next message is expected to be a BytesMessage then this should be set to byte[].class.
    If the next message is not of the expected type a ClassCastException will be thrown and the message will not be delivered.
    
    Returns:
    the payload of the next message produced for this JMSConsumer, or null if this JMSConsumer is concurrently closed
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to receive the next message due to some internal error
    
    ClassCastException - if the next message is not of the expected type
  - receivePayload
```
<T> T receivePayload(Class<T> c,
                   long timeout)
```
    Receives the next message produced for this JMSConsumer that arrives within the specified timeout period, and returns its payload, which must be of the specified type
    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 receivePayload is called within a transaction, the JMSConsumer retains the message until the transaction commits.
    
    Parameters:
    c - The class of the payload of the next message.
    If the next message is expected to be a TextMessage then this should be set to String.class.
    If the next message is expected to be a ObjectMessage then this should be set to java.io.Serializable.class.
    If the next message is expected to be a MapMessage then this should be set to java.util.Map.class.
    If the next message is expected to be a BytesMessage then this should be set to byte[].class.
    If the next message is not of the expected type a ClassCastException will be thrown and the message will not be delivered.
    
    Returns:
    the payload of the next message produced for this JMSConsumer, or null if the timeout expires or this JMSConsumer is concurrently closed
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to receive the next message due to some internal error
    
    ClassCastException - if the next message is not of the expected type
  - receivePayloadNoWait
```
<T> T receivePayloadNoWait(Class<T> c)
```
    Receives the next message produced for this JMSConsumer if one is immediately available and returns its payload, which must be of the specified type.
    If a message is not immediately available null is returned.
    If receivePayloadNoWait is called within a transaction, the JMSConsumer retains the message until the transaction commits.
    
    Parameters:
    c - The class of the payload of the next message.
    If the next message is expected to be a TextMessage then this should be set to String.class.
    If the next message is expected to be a ObjectMessage then this should be set to java.io.Serializable.class.
    If the next message is expected to be a MapMessage then this should be set to java.util.Map.class.
    If the next message is expected to be a BytesMessage then this should be set to byte[].class.
    If the next message is not of the expected type a ClassCastException will be thrown and the message will not be delivered.
    
    Returns:
    the payload of the next message produced for this JMSConsumer, or null if one is not immediately available or this JMSConsumer is concurrently closed
    
    Throws:
    
    JMSRuntimeException - if the JMS provider fails to receive the next message due to some internal error
    
    ClassCastException - if the next message is not of the expected type

Interface JMSConsumer

Method Summary

Method Detail

getMessageSelector

getMessageListener

setMessageListener

receive

receive

receiveNoWait

close

receivePayload

receivePayload

receivePayloadNoWait