org.apache.activemq.command
Class ActiveMQStreamMessage

java.lang.Object
  extended by org.apache.activemq.command.BaseCommand
      extended by org.apache.activemq.command.Message
          extended by org.apache.activemq.command.ActiveMQMessage
              extended by org.apache.activemq.command.ActiveMQStreamMessage
All Implemented Interfaces:
Message, StreamMessage, MessageReference, Command, DataStructure, MarshallAware, ScheduledMessage

public class ActiveMQStreamMessage
extends ActiveMQMessage
implements StreamMessage

A StreamMessage object is used to send a stream of primitive types in the Java programming language. It is filled and read sequentially. It inherits from the Message interface and adds a stream message body. Its methods are based largely on those found in java.io.DataInputStream and java.io.DataOutputStream.

The primitive types can be read or written explicitly using methods for each type. They may also be read or written generically as objects. For instance, a call to StreamMessage.writeInt(6) is equivalent to StreamMessage.writeObject(new Integer(6)). Both forms are provided, because the explicit form is convenient for static programming, and the object form is needed when types are not known at compile time.

When the message is first created, and when clearBody is called, the body of the message is in write-only mode. After the first call to reset has been made, the message body is in read-only mode. After a message has been sent, the client that sent it can retain and modify it without affecting the message that has been sent. The same message object can be sent multiple times. When a message has been received, the provider has called reset so that the message body is in read-only mode for the client.

If clearBody is called on a message in read-only mode, the message body is cleared and the message body is in write-only mode.

If a client attempts to read a message in write-only mode, a MessageNotReadableException is thrown.

If a client attempts to write a message in read-only mode, a MessageNotWriteableException is thrown.

StreamMessage objects support the following conversion table. The marked cases must be supported. The unmarked cases must throw a JMSException. The String-to-primitive conversions may throw a runtime exception if the primitive's valueOf() method does not accept it as a valid String representation of the primitive.

A value written as the row type can be read as the column type.

  | | boolean byte short char int long float double String byte[]
 |----------------------------------------------------------------------
 |boolean | X X |byte | X X X X X |short | X X X X |char | X X |int | X X X
 |long | X X |float | X X X |double | X X |String | X X X X X X X X |byte[] |
 X |----------------------------------------------------------------------

 

Attempting to read a null value as a primitive type must be treated as calling the primitive's corresponding valueOf(String) conversion method with a null value. Since char does not support a String conversion, attempting to read a null value as a char must throw a NullPointerException.

See Also:
Session.createStreamMessage(), BytesMessage, MapMessage, Message, ObjectMessage, TextMessage

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.activemq.command.Message
Message.MessageDestination
 
Field Summary
protected  ByteArrayOutputStream bytesOut
           
static byte DATA_STRUCTURE_TYPE
           
protected  DataInputStream dataIn
           
protected  DataOutputStream dataOut
           
protected  int remainingBytes
           
 
Fields inherited from class org.apache.activemq.command.ActiveMQMessage
acknowledgeCallback, DLQ_DELIVERY_FAILURE_CAUSE_PROPERTY
 
Fields inherited from class org.apache.activemq.command.Message
arrival, brokerInTime, brokerOutTime, compressed, content, correlationId, dataStructure, DEFAULT_MINIMUM_MESSAGE_SIZE, destination, droppable, expiration, groupID, groupSequence, marshalledProperties, messageId, ORIGINAL_EXPIRATION, originalDestination, originalTransactionId, persistent, priority, producerId, properties, readOnlyBody, readOnlyProperties, recievedByDFBridge, redeliveryCounter, replyTo, size, targetConsumerId, timestamp, transactionId, type, userID
 
Fields inherited from class org.apache.activemq.command.BaseCommand
commandId, responseRequired
 
Fields inherited from interface javax.jms.Message
DEFAULT_DELIVERY_MODE, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE
 
Fields inherited from interface org.apache.activemq.ScheduledMessage
AMQ_SCHEDULED_CRON, AMQ_SCHEDULED_DELAY, AMQ_SCHEDULED_ID, AMQ_SCHEDULED_PERIOD, AMQ_SCHEDULED_REPEAT, AMQ_SCHEDULER_ACTION, AMQ_SCHEDULER_ACTION_BROWSE, AMQ_SCHEDULER_ACTION_END_TIME, AMQ_SCHEDULER_ACTION_REMOVE, AMQ_SCHEDULER_ACTION_REMOVEALL, AMQ_SCHEDULER_ACTION_START_TIME, AMQ_SCHEDULER_MANAGEMENT_DESTINATION
 
Constructor Summary
ActiveMQStreamMessage()
           
 
Method Summary
protected  void checkWriteOnlyBody()
           
 void clearBody()
          Clears out the message body.
 void compress()
           
 Message copy()
           
 byte getDataStructureType()
           
 String getJMSXMimeType()
          Returns the MIME type of this mesage.
 void onSend()
          Send operation event listener.
 boolean readBoolean()
          Reads a boolean from the stream message.
 byte readByte()
          Reads a byte value from the stream message.
 int readBytes(byte[] value)
          Reads a byte array field from the stream message into the specified byte[] object (the read buffer).
 char readChar()
          Reads a Unicode character value from the stream message.
 double readDouble()
          Reads a double from the stream message.
 float readFloat()
          Reads a float from the stream message.
 int readInt()
          Reads a 32-bit integer from the stream message.
 long readLong()
          Reads a 64-bit integer from the stream message.
 Object readObject()
          Reads an object from the stream message.
 short readShort()
          Reads a 16-bit integer from the stream message.
 String readString()
          Reads a String from the stream message.
 void reset()
          Puts the message body in read-only mode and repositions the stream of bytes to the beginning.
 void storeContent()
           
 String toString()
           
 void writeBoolean(boolean value)
          Writes a boolean to the stream message.
 void writeByte(byte value)
          Writes a byte to the stream message.
 void writeBytes(byte[] value)
          Writes a byte array field to the stream message.
 void writeBytes(byte[] value, int offset, int length)
          Writes a portion of a byte array as a byte array field to the stream message.
 void writeChar(char value)
          Writes a char to the stream message.
 void writeDouble(double value)
          Writes a double to the stream message.
 void writeFloat(float value)
          Writes a float to the stream message.
 void writeInt(int value)
          Writes an int to the stream message.
 void writeLong(long value)
          Writes a long to the stream message.
 void writeObject(Object value)
          Writes an object to the stream message.
 void writeShort(short value)
          Writes a short to the stream message.
 void writeString(String value)
          Writes a String to the stream message.
 
Methods inherited from class org.apache.activemq.command.ActiveMQMessage
acknowledge, checkReadOnlyBody, checkValidObject, checkValidScheduled, clearProperties, convertScheduled, copy, decodeString, encodeString, equals, getAcknowledgeCallback, getAllPropertyNames, getBooleanProperty, getByteProperty, getDoubleProperty, getFloatProperty, getIntProperty, getJMSCorrelationID, getJMSCorrelationIDAsBytes, getJMSDeliveryMode, getJMSDestination, getJMSExpiration, getJMSMessageID, getJMSPriority, getJMSRedelivered, getJMSReplyTo, getJMSTimestamp, getJMSType, getLongProperty, getObjectProperty, getPropertyNames, getShortProperty, getStringProperty, hashCode, propertyExists, setAcknowledgeCallback, setBooleanProperty, setBooleanProperty, setByteProperty, setDoubleProperty, setFloatProperty, setIntProperty, setJMSCorrelationID, setJMSCorrelationIDAsBytes, setJMSDeliveryMode, setJMSDestination, setJMSExpiration, setJMSMessageID, setJMSMessageID, setJMSPriority, setJMSRedelivered, setJMSReplyTo, setJMSTimestamp, setJMSType, setLongProperty, setObjectProperty, setObjectProperty, setProperties, setShortProperty, setStringProperty, visit
 
Methods inherited from class org.apache.activemq.command.Message
afterMarshall, afterUnmarshall, beforeMarshall, beforeUnmarshall, clearMarshalledState, copy, decrementReferenceCount, doCompress, getArrival, getBrokerInTime, getBrokerOutTime, getBrokerPath, getCluster, getConnection, getContent, getCorrelationId, getDataStructure, getDestination, getExpiration, getGroupID, getGroupSequence, getMarshalledProperties, getMemoryUsage, getMessage, getMessageHardRef, getMessageId, getMinimumMessageSize, getOriginalDestination, getOriginalTransactionId, getPriority, getProducerId, getProperties, getProperty, getRedeliveryCounter, getReferenceCount, getRegionDestination, getReplyTo, getSize, getTargetConsumerId, getTimestamp, getTransactionId, getType, getUserID, incrementRedeliveryCounter, incrementReferenceCount, isAdvisory, isCompressed, isDroppable, isDropped, isExpired, isInTransaction, isMarshallAware, isMessage, isPersistent, isReadOnlyBody, isReadOnlyProperties, isRecievedByDFBridge, isRedelivered, lazyCreateProperties, onMessageRolledBack, removeProperty, setArrival, setBrokerInTime, setBrokerOutTime, setBrokerPath, setCluster, setCompressed, setConnection, setContent, setCorrelationId, setDataStructure, setDestination, setDroppable, setExpiration, setGroupID, setGroupSequence, setMarshalledProperties, setMemoryUsage, setMessageId, setOriginalDestination, setOriginalTransactionId, setPersistent, setPriority, setProducerId, setProperty, setReadOnlyBody, setReadOnlyProperties, setRecievedByDFBridge, setRedelivered, setRedeliveryCounter, setRegionDestination, setReplyTo, setTargetConsumerId, setTimestamp, setTransactionId, setType, setUserID, toString
 
Methods inherited from class org.apache.activemq.command.BaseCommand
copy, getCommandId, getFrom, getTo, isBrokerInfo, isConnectionControl, isMessageAck, isMessageDispatch, isMessageDispatchNotification, isResponse, isResponseRequired, isShutdownInfo, isWireFormatInfo, setCommandId, setFrom, setResponseRequired, setTo
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface javax.jms.Message
acknowledge, clearProperties, getBooleanProperty, getByteProperty, getDoubleProperty, getFloatProperty, getIntProperty, getJMSCorrelationID, getJMSCorrelationIDAsBytes, getJMSDeliveryMode, getJMSDestination, getJMSExpiration, getJMSMessageID, getJMSPriority, getJMSRedelivered, getJMSReplyTo, getJMSTimestamp, getJMSType, getLongProperty, getObjectProperty, getPropertyNames, getShortProperty, getStringProperty, propertyExists, setBooleanProperty, setByteProperty, setDoubleProperty, setFloatProperty, setIntProperty, setJMSCorrelationID, setJMSCorrelationIDAsBytes, setJMSDeliveryMode, setJMSDestination, setJMSExpiration, setJMSMessageID, setJMSPriority, setJMSRedelivered, setJMSReplyTo, setJMSTimestamp, setJMSType, setLongProperty, setObjectProperty, setShortProperty, setStringProperty
 

Field Detail

DATA_STRUCTURE_TYPE

public static final byte DATA_STRUCTURE_TYPE
See Also:
Constant Field Values

dataOut

protected transient DataOutputStream dataOut

bytesOut

protected transient ByteArrayOutputStream bytesOut

dataIn

protected transient DataInputStream dataIn

remainingBytes

protected transient int remainingBytes
Constructor Detail

ActiveMQStreamMessage

public ActiveMQStreamMessage()
Method Detail

copy

public Message copy()
Overrides:
copy in class ActiveMQMessage

onSend

public void onSend()
            throws JMSException
Description copied from class: ActiveMQMessage
Send operation event listener. Used to get the message ready to be sent.

Overrides:
onSend in class ActiveMQMessage
Throws:
JMSException

storeContent

public void storeContent()
Overrides:
storeContent in class ActiveMQMessage

getDataStructureType

public byte getDataStructureType()
Specified by:
getDataStructureType in interface DataStructure
Overrides:
getDataStructureType in class ActiveMQMessage
Returns:
The type of the data structure

getJMSXMimeType

public String getJMSXMimeType()
Description copied from interface: Message
Returns the MIME type of this mesage. This can be used in selectors to filter on the MIME types of the different JMS messages, or in the case of BlobMessage it allows you to create a selector on the MIME type of the BLOB body

Overrides:
getJMSXMimeType in class ActiveMQMessage

clearBody

public void clearBody()
               throws JMSException
Clears out the message body. Clearing a message's body does not clear its header values or property entries.

If this message body was read-only, calling this method leaves the message body in the same state as an empty body in a newly created message.

Specified by:
clearBody in interface Message
Overrides:
clearBody in class ActiveMQMessage
Throws:
JMSException - if the JMS provider fails to clear the message body due to some internal error.

readBoolean

public boolean readBoolean()
                    throws JMSException
Reads a boolean from the stream message.

Specified by:
readBoolean in interface StreamMessage
Returns:
the boolean value read
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readByte

public byte readByte()
              throws JMSException
Reads a byte value from the stream message.

Specified by:
readByte in interface StreamMessage
Returns:
the next byte from the stream message as a 8-bit byte
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readShort

public short readShort()
                throws JMSException
Reads a 16-bit integer from the stream message.

Specified by:
readShort in interface StreamMessage
Returns:
a 16-bit integer from the stream message
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readChar

public char readChar()
              throws JMSException
Reads a Unicode character value from the stream message.

Specified by:
readChar in interface StreamMessage
Returns:
a Unicode character from the stream message
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid
MessageNotReadableException - if the message is in write-only mode.

readInt

public int readInt()
            throws JMSException
Reads a 32-bit integer from the stream message.

Specified by:
readInt in interface StreamMessage
Returns:
a 32-bit integer value from the stream message, interpreted as an int
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readLong

public long readLong()
              throws JMSException
Reads a 64-bit integer from the stream message.

Specified by:
readLong in interface StreamMessage
Returns:
a 64-bit integer value from the stream message, interpreted as a long
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readFloat

public float readFloat()
                throws JMSException
Reads a float from the stream message.

Specified by:
readFloat in interface StreamMessage
Returns:
a float value from the stream message
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readDouble

public double readDouble()
                  throws JMSException
Reads a double from the stream message.

Specified by:
readDouble in interface StreamMessage
Returns:
a double value from the stream message
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readString

public String readString()
                  throws JMSException
Reads a String from the stream message.

Specified by:
readString in interface StreamMessage
Returns:
a Unicode string from the stream message
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.

readBytes

public int readBytes(byte[] value)
              throws JMSException
Reads a byte array field from the stream message into the specified byte[] object (the read buffer).

To read the field value, readBytes should be successively called until it returns a value less than the length of the read buffer. The value of the bytes in the buffer following the last byte read is undefined.

If readBytes returns a value equal to the length of the buffer, a subsequent readBytes call must be made. If there are no more bytes to be read, this call returns -1.

If the byte array field value is null, readBytes returns -1.

If the byte array field value is empty, readBytes returns 0.

Once the first readBytes call on a byte[] field value has been made, the full value of the field must be read before it is valid to read the next field. An attempt to read the next field before that has been done will throw a MessageFormatException.

To read the byte field value into a new byte[] object, use the readObject method.

Specified by:
readBytes in interface StreamMessage
Parameters:
value - the buffer into which the data is read
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of the byte field has been reached
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.
See Also:
readObject()

readObject

public Object readObject()
                  throws JMSException
Reads an object from the stream message.

This method can be used to return, in objectified format, an object in the Java programming language ("Java object") that has been written to the stream with the equivalent writeObject method call, or its equivalent primitive writetype method.

Note that byte values are returned as byte[], not Byte[].

An attempt to call readObject to read a byte field value into a new byte[] object before the full value of the byte field has been read will throw a MessageFormatException.

Specified by:
readObject in interface StreamMessage
Returns:
a Java object from the stream message, in objectified format (for example, if the object was written as an int, an Integer is returned)
Throws:
JMSException - if the JMS provider fails to read the message due to some internal error.
MessageEOFException - if unexpected end of message stream has been reached.
MessageFormatException - if this type conversion is invalid.
MessageNotReadableException - if the message is in write-only mode.
See Also:
readBytes(byte[] value)

writeBoolean

public void writeBoolean(boolean value)
                  throws JMSException
Writes a boolean to the stream message. The value true is written as the value (byte)1; the value false is written as the value (byte)0.

Specified by:
writeBoolean in interface StreamMessage
Parameters:
value - the boolean value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeByte

public void writeByte(byte value)
               throws JMSException
Writes a byte to the stream message.

Specified by:
writeByte in interface StreamMessage
Parameters:
value - the byte value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeShort

public void writeShort(short value)
                throws JMSException
Writes a short to the stream message.

Specified by:
writeShort in interface StreamMessage
Parameters:
value - the short value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeChar

public void writeChar(char value)
               throws JMSException
Writes a char to the stream message.

Specified by:
writeChar in interface StreamMessage
Parameters:
value - the char value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeInt

public void writeInt(int value)
              throws JMSException
Writes an int to the stream message.

Specified by:
writeInt in interface StreamMessage
Parameters:
value - the int value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeLong

public void writeLong(long value)
               throws JMSException
Writes a long to the stream message.

Specified by:
writeLong in interface StreamMessage
Parameters:
value - the long value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeFloat

public void writeFloat(float value)
                throws JMSException
Writes a float to the stream message.

Specified by:
writeFloat in interface StreamMessage
Parameters:
value - the float value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeDouble

public void writeDouble(double value)
                 throws JMSException
Writes a double to the stream message.

Specified by:
writeDouble in interface StreamMessage
Parameters:
value - the double value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeString

public void writeString(String value)
                 throws JMSException
Writes a String to the stream message.

Specified by:
writeString in interface StreamMessage
Parameters:
value - the String value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeBytes

public void writeBytes(byte[] value)
                throws JMSException
Writes a byte array field to the stream message.

The byte array value is written to the message as a byte array field. Consecutively written byte array fields are treated as two distinct fields when the fields are read.

Specified by:
writeBytes in interface StreamMessage
Parameters:
value - the byte array value to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeBytes

public void writeBytes(byte[] value,
                       int offset,
                       int length)
                throws JMSException
Writes a portion of a byte array as a byte array field to the stream message.

The a portion of the byte array value is written to the message as a byte array field. Consecutively written byte array fields are treated as two distinct fields when the fields are read.

Specified by:
writeBytes in interface StreamMessage
Parameters:
value - the byte array value to be written
offset - the initial offset within the byte array
length - the number of bytes to use
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageNotWriteableException - if the message is in read-only mode.

writeObject

public void writeObject(Object value)
                 throws JMSException
Writes an object to the stream message.

This method works only for the objectified primitive object types (Integer, Double, Long ...), String objects, and byte arrays.

Specified by:
writeObject in interface StreamMessage
Parameters:
value - the Java object to be written
Throws:
JMSException - if the JMS provider fails to write the message due to some internal error.
MessageFormatException - if the object is invalid.
MessageNotWriteableException - if the message is in read-only mode.

reset

public void reset()
           throws JMSException
Puts the message body in read-only mode and repositions the stream of bytes to the beginning.

Specified by:
reset in interface StreamMessage
Throws:
JMSException - if an internal error occurs

checkWriteOnlyBody

protected void checkWriteOnlyBody()
                           throws MessageNotReadableException
Throws:
MessageNotReadableException

compress

public void compress()
              throws IOException
Overrides:
compress in class Message
Throws:
IOException

toString

public String toString()
Overrides:
toString in class Message


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