org.exolab.jms.message
Class StreamMessageImpl

java.lang.Object
  |
  +--org.exolab.jms.message.MessageImpl
        |
        +--org.exolab.jms.message.StreamMessageImpl
All Implemented Interfaces:
java.lang.Cloneable, java.io.Externalizable, javax.jms.Message, java.io.Serializable, javax.jms.StreamMessage

public final class StreamMessageImpl
extends MessageImpl
implements javax.jms.StreamMessage

This class implements the StreamMessage interface.

A StreamMessage is used to send a stream of Java primitives. It is filled and read sequentially. It inherits from Message and adds a stream message body. It's 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. When a message has been sent, by definition, the provider calls reset in order to read it's content, and 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.

Stream messages 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 primitives 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 Java 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 NullPointerException.

Version:
$Revision: 1.2 $ $Date: 2005/05/24 13:27:10 $
Author:
Jim Mourikis, Tim Anderson
See Also:
StreamMessage, Serialized Form

Fields inherited from class org.exolab.jms.message.MessageImpl
_acceptedTime, _bodyReadOnly, _connectionId, _processed, _propertiesReadOnly, _sequenceNumber, EMPTY
 
Fields inherited from interface javax.jms.Message
DEFAULT_DELIVERY_MODE, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE
 
Constructor Summary
StreamMessageImpl()
          Construct a new StreamMessage.
 
Method Summary
 void clearBody()
          Overide the super class method to reset the streams, and put the message body in write only mode
 java.lang.Object clone()
          Clone an instance of this object
 boolean readBoolean()
          Read a boolean from the bytes message stream
 byte readByte()
          Read a byte value from the stream message
 int readBytes(byte[] value)
          Read a byte array field from the stream message into the specified byte[] object (the read buffer).
 char readChar()
           
 double readDouble()
          Read a double from the stream message
 void readExternal(java.io.ObjectInput in)
          Serialize in this message's data
 float readFloat()
          Read a float from the stream message
 int readInt()
           
 long readLong()
           
 java.lang.Object readObject()
          Read a Java object from the stream message
 short readShort()
          Read a 16-bit number from the stream message.
 java.lang.String readString()
          Read in a string from the stream message
 void reset()
          Put the message body in read-only mode, and reposition the stream to the beginning
 void setReadOnly(boolean readOnly)
          Set the read-only mode of the message.
 void writeBoolean(boolean value)
          Write a boolean to the stream message.
 void writeByte(byte value)
          Write out a byte to the stream message
 void writeBytes(byte[] value)
          Write a byte array field to the stream message
 void writeBytes(byte[] value, int offset, int length)
          Write a portion of a byte array as a byte array field to the stream message
 void writeChar(char value)
          Write a char to the stream message
 void writeDouble(double value)
          Write a double to the stream message
 void writeExternal(java.io.ObjectOutput out)
          Serialize out this message's data
 void writeFloat(float value)
          Write a float to the stream message
 void writeInt(int value)
          Write an int to the stream message
 void writeLong(long value)
          Write a long to the stream message
 void writeObject(java.lang.Object value)
          Write a Java object to the stream message
 void writeShort(short value)
          Write a short to the stream message
 void writeString(java.lang.String value)
          Write a string to the stream message
 
Methods inherited from class org.exolab.jms.message.MessageImpl
acknowledge, checkPropertyWrite, checkRead, checkWrite, clearProperties, getAcceptedTime, getAckMessageID, getBooleanProperty, getByteProperty, getConnectionId, getConsumerId, getDoubleProperty, getFloatProperty, getId, getIntProperty, getJMSCorrelationID, getJMSCorrelationIDAsBytes, getJMSDeliveryMode, getJMSDestination, getJMSExpiration, getJMSMessageID, getJMSPriority, getJMSRedelivered, getJMSReplyTo, getJMSTimestamp, getJMSType, getLongProperty, getMessageId, getObjectProperty, getProcessed, getPropertyNames, getReadOnly, getSequenceNumber, getShortProperty, getStringProperty, getWildcard, propertyExists, setAcceptedTime, setBooleanProperty, setByteProperty, setConnectionId, setConsumerId, setDoubleProperty, setFloatProperty, setIntProperty, setJMSCorrelationID, setJMSCorrelationIDAsBytes, setJMSDeliveryMode, setJMSDestination, setJMSExpiration, setJMSMessageID, setJMSPriority, setJMSRedelivered, setJMSReplyTo, setJMSTimestamp, setJMSType, setJMSXRcvTimestamp, setLongProperty, setObjectProperty, setProcessed, setSequenceNumber, setSession, setShortProperty, setStringProperty, setWildcard
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, 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
 

Constructor Detail

StreamMessageImpl

public StreamMessageImpl()
                  throws javax.jms.JMSException
Construct a new StreamMessage. When first created, the message is in write-only mode.
Throws:
javax.jms.JMSException - if the message type can't be set, or an I/O error occurs
Method Detail

clone

public final java.lang.Object clone()
                             throws java.lang.CloneNotSupportedException
Clone an instance of this object
Overrides:
clone in class MessageImpl
Returns:
a copy of this object
Throws:
java.lang.CloneNotSupportedException - if object or attributes aren't cloneable

writeExternal

public final void writeExternal(java.io.ObjectOutput out)
                         throws java.io.IOException
Serialize out this message's data
Overrides:
writeExternal in class MessageImpl
Parameters:
out - the stream to serialize out to
Throws:
java.io.IOException - if any I/O exceptions occurr

readExternal

public final void readExternal(java.io.ObjectInput in)
                        throws java.lang.ClassNotFoundException,
                               java.io.IOException
Serialize in this message's data
Overrides:
readExternal in class MessageImpl
Parameters:
in - the stream to serialize in from
Throws:
java.lang.ClassNotFoundException - if the class for an object being restored cannot be found.
java.io.IOException - if any I/O exceptions occur

readBoolean

public final boolean readBoolean()
                          throws javax.jms.JMSException
Read a boolean from the bytes message stream
Specified by:
readBoolean in interface javax.jms.StreamMessage
Returns:
the boolean value read
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode

readByte

public final byte readByte()
                    throws javax.jms.JMSException
Read a byte value from the stream message
Specified by:
readByte in interface javax.jms.StreamMessage
Returns:
the next byte from the stream message as an 8-bit byte
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode
java.lang.NumberFormatException - if numeric conversion is invalid

readShort

public final short readShort()
                      throws javax.jms.JMSException
Read a 16-bit number from the stream message.
Specified by:
readShort in interface javax.jms.StreamMessage
Returns:
a 16-bit number from the stream message
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode
java.lang.NumberFormatException - if numeric conversion is invalid

readChar

public final char readChar()
                    throws javax.jms.JMSException
Specified by:
readChar in interface javax.jms.StreamMessage

readInt

public final int readInt()
                  throws javax.jms.JMSException
Specified by:
readInt in interface javax.jms.StreamMessage

readLong

public final long readLong()
                    throws javax.jms.JMSException
Specified by:
readLong in interface javax.jms.StreamMessage

readFloat

public final float readFloat()
                      throws javax.jms.JMSException
Read a float from the stream message
Specified by:
readFloat in interface javax.jms.StreamMessage
Returns:
a float value from the stream message
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode
NullPointerException - if the value is null
java.lang.NumberFormatException - if numeric conversion is invalid

readDouble

public final double readDouble()
                        throws javax.jms.JMSException
Read a double from the stream message
Specified by:
readDouble in interface javax.jms.StreamMessage
Returns:
a double value from the stream message
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode
NullPointerException - if the value is null
java.lang.NumberFormatException - if numeric conversion is invalid

readString

public final java.lang.String readString()
                                  throws javax.jms.JMSException
Read in a string from the stream message
Specified by:
readString in interface javax.jms.StreamMessage
Returns:
a Unicode string from the stream message
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode

readBytes

public final int readBytes(byte[] value)
                    throws javax.jms.JMSException
Read 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 are 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 will return -1.

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

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

Once the first readBytes call on a byte[] field value has been done, 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 javax.jms.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:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if an end of message stream
javax.jms.MessageFormatException - if this type conversion is invalid
javax.jms.MessageNotReadableException - if message is in write-only mode

readObject

public final java.lang.Object readObject()
                                  throws javax.jms.JMSException
Read a Java object from the stream message

Note that this method can be used to return in objectified format, an object that had been written to the stream with the equivalent writeObject method call, or it's equivalent primitive write method.

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

Specified by:
readObject in interface javax.jms.StreamMessage
Returns:
a Java object from the stream message, in objectified format (eg. if it set as an int, then a Integer is returned).
Throws:
javax.jms.JMSException - if JMS fails to read message due to some internal JMS error
javax.jms.MessageEOFException - if end of message stream
javax.jms.MessageNotReadableException - if message is in write-only mode

writeBoolean

public final void writeBoolean(boolean value)
                        throws javax.jms.JMSException
Write a boolean to the stream message. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.
Specified by:
writeBoolean in interface javax.jms.StreamMessage
Parameters:
value - the boolean value to be written.
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeByte

public final void writeByte(byte value)
                     throws javax.jms.JMSException
Write out a byte to the stream message
Specified by:
writeByte in interface javax.jms.StreamMessage
Parameters:
value - the byte value to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeShort

public final void writeShort(short value)
                      throws javax.jms.JMSException
Write a short to the stream message
Specified by:
writeShort in interface javax.jms.StreamMessage
Parameters:
value - the short to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeChar

public final void writeChar(char value)
                     throws javax.jms.JMSException
Write a char to the stream message
Specified by:
writeChar in interface javax.jms.StreamMessage
Parameters:
value - the char value to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeInt

public final void writeInt(int value)
                    throws javax.jms.JMSException
Write an int to the stream message
Specified by:
writeInt in interface javax.jms.StreamMessage
Parameters:
value - the int to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeLong

public final void writeLong(long value)
                     throws javax.jms.JMSException
Write a long to the stream message
Specified by:
writeLong in interface javax.jms.StreamMessage
Parameters:
value - the long to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeFloat

public final void writeFloat(float value)
                      throws javax.jms.JMSException
Write a float to the stream message
Specified by:
writeFloat in interface javax.jms.StreamMessage
Parameters:
value - the float value to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeDouble

public final void writeDouble(double value)
                       throws javax.jms.JMSException
Write a double to the stream message
Specified by:
writeDouble in interface javax.jms.StreamMessage
Parameters:
value - the double value to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode

writeString

public final void writeString(java.lang.String value)
                       throws javax.jms.JMSException
Write a string to the stream message
Specified by:
writeString in interface javax.jms.StreamMessage
Parameters:
value - the String value to be written
Throws:
javax.jms.JMSException - if JMS fails to write message due to some internal JMS error
javax.jms.MessageNotWriteableException - if message in read-only mode
NullPointerException - if value is null

writeBytes

public final void writeBytes(byte[] value)
                      throws javax.jms.JMSException
Write a byte array field to the stream message

The byte array value is written as a byte array field into the StreamMessage. Consecutively written byte array fields are treated as two distinct fields when reading byte array fields.

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

writeBytes

public void writeBytes(byte[] value,
                       int offset,
                       int length)
                throws javax.jms.JMSException
Write 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 as a byte array field into the StreamMessage. Consecutively written byte array fields are treated as two distinct fields when reading byte array fields.

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

writeObject

public void writeObject(java.lang.Object value)
                 throws javax.jms.JMSException
Write a Java object to the stream message

Note that this method only works for the objectified primitive object types (Integer, Double, Long ...), String's and byte arrays.

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

reset

public void reset()
           throws javax.jms.JMSException
Put the message body in read-only mode, and reposition the stream to the beginning
Specified by:
reset in interface javax.jms.StreamMessage
Throws:
javax.jms.JMSException - if JMS fails to reset the message due to some internal JMS error

clearBody

public void clearBody()
               throws javax.jms.JMSException
Overide the super class method to reset the streams, and put the message body in write only mode
Specified by:
clearBody in interface javax.jms.Message
Overrides:
clearBody in class MessageImpl
Throws:
javax.jms.JMSException - if JMS fails to reset the message due to some internal JMS error.

setReadOnly

public final void setReadOnly(boolean readOnly)
                       throws javax.jms.JMSException
Set the read-only mode of the message. If read-only, resets the message for reading
Overrides:
setReadOnly in class MessageImpl
Parameters:
readOnly - if true, make the message body and properties
Throws:
javax.jms.JMSException - if the read-only mode cannot be changed


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