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Oracle® Streams Advanced Queuing Java API Reference
11g Release 2 (11.2)

E10768-01


javax.jms
Interface StreamMessage

All Superinterfaces:
Message
All Known Implementing Classes:
AQjmsStreamMessage

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.

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

Field Summary

 

Fields inherited from interface javax.jms.Message
DEFAULT_DELIVERY_MODE, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE

 

Method Summary
 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.
 java.lang.Object readObject()
          Reads an object from the stream message.
 short readShort()
          Reads a 16-bit integer from the stream message.
 java.lang.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(java.lang.Object value)
          Writes an object to the stream message.
 void writeShort(short value)
          Writes a short to the stream message.
 void writeString(java.lang.String value)
          Writes a String to the stream message.

 

Methods inherited from interface javax.jms.Message
acknowledge, clearBody, 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

 

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

java.lang.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

java.lang.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.

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(java.lang.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(java.lang.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.

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Oracle® Streams Advanced Queuing Java API Reference
11g Release 2 (11.2)

E10768-01


Copyright © 2001 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.