javax.jms

Interface StreamMessage

All Superinterfaces:

Message

public interface StreamMessage
extends Message

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.

Version:

1.0 - 6 August 1998

Author:

Mark Hapner, Rich Burridge

See Also:

Session.createStreamMessage(), BytesMessage, MapMessage, Message, ObjectMessage, TextMessage

Field Summary

Fields inherited from interface javax.jms.Message

DEFAULT_DELIVERY_DELAY, DEFAULT_DELIVERY_MODE, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE

Method Summary

Methods

Modifier and Type	Method and Description
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 to the beginning.
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 interface javax.jms.Message

acknowledge, clearBody, clearProperties, getBody, getBooleanProperty, getByteProperty, getDoubleProperty, getFloatProperty, getIntProperty, getJMSCorrelationID, getJMSCorrelationIDAsBytes, getJMSDeliveryMode, getJMSDeliveryTime, getJMSDestination, getJMSExpiration, getJMSMessageID, getJMSPriority, getJMSRedelivered, getJMSReplyTo, getJMSTimestamp, getJMSType, getLongProperty, getObjectProperty, getPropertyNames, getShortProperty, getStringProperty, isBodyAssignableTo, propertyExists, setBooleanProperty, setByteProperty, setDoubleProperty, setFloatProperty, setIntProperty, setJMSCorrelationID, setJMSCorrelationIDAsBytes, setJMSDeliveryMode, setJMSDeliveryTime, setJMSDestination, setJMSExpiration, setJMSMessageID, setJMSPriority, setJMSRedelivered, setJMSReplyTo, setJMSTimestamp, setJMSType, setLongProperty, setObjectProperty, setShortProperty, setStringProperty

Method Detail

readBoolean

boolean readBoolean()
                    throws JMSException

Reads a boolean from the stream message.

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

byte readByte()
              throws JMSException

Reads a byte value from the stream message.

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

short readShort()
                throws JMSException

Reads a 16-bit integer from the stream message.

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

char readChar()
              throws JMSException

Reads a Unicode character value from the stream message.

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

int readInt()
            throws JMSException

Reads a 32-bit integer from the stream message.

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

long readLong()
              throws JMSException

Reads a 64-bit integer from the stream message.

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

float readFloat()
                throws JMSException

Reads a float from the stream message.

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

double readDouble()
                  throws JMSException

Reads a double from the stream message.

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

String readString()
                  throws JMSException

Reads a String from the stream message.

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

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.

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

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 write<I>type</I> 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.

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

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.

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

void writeByte(byte value)
               throws JMSException

Writes a byte to the stream message.

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

void writeShort(short value)
                throws JMSException

Writes a short to the stream message.

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

void writeChar(char value)
               throws JMSException

Writes a char to the stream message.

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

void writeInt(int value)
              throws JMSException

Writes an int to the stream message.

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

void writeLong(long value)
               throws JMSException

Writes a long to the stream message.

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

void writeFloat(float value)
                throws JMSException

Writes a float to the stream message.

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

void writeDouble(double value)
                 throws JMSException

Writes a double to the stream message.

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

void writeString(String value)
                 throws JMSException

Writes a String to the stream message.

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

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.

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

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.

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

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.

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

void reset()
           throws JMSException

Puts the message body in read-only mode and repositions the stream to the beginning.

Throws:

JMSException - if the JMS provider fails to reset the message due to some internal error.

MessageFormatException - if the message has an invalid format.