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