com.ibm.jms
Class JMSStreamMessage

java.lang.Object
  |
  +--com.ibm.jms.JMSMessage
        |
        +--com.ibm.jms.JMSStreamMessage
All Implemented Interfaces:
javax.jms.Message, java.io.Serializable, javax.jms.StreamMessage

public class JMSStreamMessage
extends JMSMessage
implements javax.jms.StreamMessage

A StreamMessage is used to send a stream of Java primitives. It is filled and read sequentially. It inherits from JMSMessage 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 can also be read or written generically as objects. For example, 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 the reset() method has been made, the message body is in read-only mode. When a message has been sent, the provider always calls the reset() method to read its content. Likewise, when a message has been received, the provider calls 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 are supported and the unmarked cases throw a JMSException. The String to primitive conversions 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 is treated as calling the primitive's corresponding valueOf(String) conversion method with a null value. Because char does not support a String conversion, attempting to read a null value as a char throws a NullPointerException.

See Also:
Serialized Form

Field Summary
   
Fields inherited from interface javax.jms.Message
DEFAULT_DELIVERY_MODE, DEFAULT_PRIORITY, DEFAULT_TIME_TO_LIVE
 
Method Summary
 void clearBody()
          Clears the message body.
 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 a Java object from the stream message.
 short readShort()
          Reads a 16-bit integer from the stream message.
 java.lang.String readString()
          Reads in a String from the stream message.
 void reset()
          Puts the message in read-only mode, and repositions the stream to the beginning.
 java.lang.String toString()
          Gets a String containing a formatted version of the Message.
 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 to the stream message.
 void writeBytes(byte[] value, int offset, int length)
          Writes a portion of a byte array 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 a Java object to the stream message.
 void writeShort(short value)
          Write a short to the stream message.
 void writeString(java.lang.String value)
          Writes a String to the stream message.
 
Methods inherited from class com.ibm.jms.JMSMessage
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
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, 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
 

Method Detail

clearBody

public void clearBody()
               throws javax.jms.JMSException
Clears the message body. All other parts of the message are left untouched.

Specified by:
clearBody in interface javax.jms.Message
Specified by:
clearBody in class JMSMessage
Throws:
javax.jms.JMSException - if the action fails to due to an internal JMS error.

readBoolean

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

Specified by:
readBoolean in interface javax.jms.StreamMessage
Returns:
the boolean value read.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readByte

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

Specified by:
readByte in interface javax.jms.StreamMessage
Returns:
the next byte from the stream message as a 8-bit byte.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readBytes

public int readBytes(byte[] value)
              throws javax.jms.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 values 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.

After the first readBytes() call on a byte[] field value has been made, the full value of the field must be read before the next field can be read. An attempt to read the next field before that has been done will throw a MessageFormatException.

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 the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readChar

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

Specified by:
readChar in interface javax.jms.StreamMessage
Returns:
a Unicode character from the stream message.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readDouble

public double readDouble()
                  throws javax.jms.JMSException
Reads 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 the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readFloat

public float readFloat()
                throws javax.jms.JMSException
Reads 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 the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readInt

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

Specified by:
readInt in interface javax.jms.StreamMessage
Returns:
a 32-bit integer value from the stream message, interpreted as an int.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readLong

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

Specified by:
readLong in interface javax.jms.StreamMessage
Returns:
a 64-bit integer value from the stream message, interpreted as a long.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readObject

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

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 its equivalent primitive write() method.

Specified by:
readObject in interface javax.jms.StreamMessage
Returns:
a Java object from the stream message, in 'objectified' format.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readShort

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

Specified by:
readShort in interface javax.jms.StreamMessage
Returns:
a 16-bit integer from the stream message.
Throws:
javax.jms.JMSException - if JMS fails to read the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

readString

public java.lang.String readString()
                            throws javax.jms.JMSException
Reads 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 the message due to an internal JMS error.
javax.jms.MessageEOFException - if an end of message stream.
javax.jms.MessageFormatException - if this type conversion is not valid.
javax.jms.MessageNotReadableException - if the message is in write-only mode.

reset

public void reset()
           throws javax.jms.JMSException
Puts the message in read-only mode, and repositions 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 an internal JMS error.
javax.jms.MessageFormatException - if the message's format is not valid

toString

public java.lang.String toString()
Gets a String containing a formatted version of the Message.

Overrides:
toString in class JMSMessage
Returns:
the String version of the message.

writeBoolean

public void writeBoolean(boolean value)
                  throws javax.jms.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 javax.jms.StreamMessage
Parameters:
value - the boolean value to be written.
Throws:
javax.jms.JMSException - if JMS fails to write the boolean to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeByte

public void writeByte(byte value)
               throws javax.jms.JMSException
Writes 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 the byte to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeBytes

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

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 the byte array to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeBytes

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

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 use.
Throws:
javax.jms.JMSException - if JMS fails to write the byte array portion to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeChar

public void writeChar(char value)
               throws javax.jms.JMSException
Writes 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 the char to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeDouble

public void writeDouble(double value)
                 throws javax.jms.JMSException
Writes 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 the double to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeFloat

public void writeFloat(float value)
                throws javax.jms.JMSException
Writes 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 the float to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeInt

public void writeInt(int value)
              throws javax.jms.JMSException
Writes 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 the int to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeLong

public void writeLong(long value)
               throws javax.jms.JMSException
Writes 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 the long to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeObject

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

This method only works for the 'objectified' primitive object types (Integer, Double, Long ...), Strings 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 the object to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.
javax.jms.MessageFormatException - if the object is not valid

writeShort

public 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 the short to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

writeString

public void writeString(java.lang.String value)
                 throws javax.jms.JMSException
Writes 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 the String to the message due to an internal JMS error.
javax.jms.MessageNotWriteableException - if the message is in read-only mode.

(c) Copyright IBM Corp. 2005. All Rights Reserved.