Inherits from KMMessage : KCObject : NSObject
Declared in KMStreamMessage.h

Overview

A StreamMessage object is used to send a stream of primitive types. 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 the Java platform: 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 KMMessageNotReadableException is thrown.

If a client attempts to write a message in read-only mode, a KMMessageNotWriteableException is thrown.

StreamMessage objects support the following conversion table. The marked cases must be supported. The unmarked cases must throw a KMJMSException. 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 an exception.

Tasks

Instance Methods

readBoolean

Reads a boolean from the stream message.

- (BOOL)readBoolean

Return Value

the boolean value read

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readByte

Reads a byte value from the stream message.

- (char)readByte

Return Value

the next byte from the stream message as a 8-bit byte

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readBytes:

Reads a byte array field from the stream message into the specified byte[] object (the read buffer).

- (int)readBytes:(NSData *)value

Parameters

value

the buffer into which the data is read

Return Value

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

Discussion

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 KMMessageFormatException.

To read the byte field value into a new byte[] object, use the readObject method.

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

See Also

Declared In

KMStreamMessage.h

readChar

Reads a Unicode character value from the stream message.

- (char)readChar

Return Value

a Unicode character from the stream message

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readDouble

Reads a double from the stream message.

- (double)readDouble

Return Value

a double value from the stream message

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readFloat

Reads a float from the stream message.

- (float)readFloat

Return Value

a float value from the stream message

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readInt

Reads a 32-bit integer from the stream message.

- (int)readInt

Return Value

a 32-bit integer value from the stream message, interpreted as an int

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readLong

Reads a 64-bit integer from the stream message.

- (long long)readLong

Return Value

a 64-bit integer value from the stream message, interpreted as a long

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readObject

Reads an object from the stream message.

- (KCObject *)readObject

Return Value

a object from the stream message, in objectified format (for example, if the object was written as an int, an NSNumber is returned)

Discussion

This method can be used to return, in objectified format, an 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 NSData, 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 KMMessageFormatException.

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readShort

Reads a 16-bit integer from the stream message.

- (short)readShort

Return Value

a 16-bit integer from the stream message

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

readString

Reads a String from the stream message.

- (NSString *)readString

Return Value

a Unicode string from the stream message

Exceptions

KMJMSException

if the JMS provider fails to read the message due to some internal error.

KMMessageEOFException

if unexpected end of message stream has been reached.

KMMessageFormatException

if this type conversion is invalid.

KMMessageNotReadableException

if the message is in write-only mode.

Declared In

KMStreamMessage.h

reset

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

- (void)reset

Exceptions

KMJMSException

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

KMMessageFormatException

if the message has an invalid format.

Declared In

KMStreamMessage.h

writeBoolean:

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.

- (void)writeBoolean:(BOOL)value

Parameters

value

the boolean value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeByte:

Writes a byte to the stream message.

- (void)writeByte:(char)value

Parameters

value

the byte value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeBytes:

Writes a byte array field to the stream message.

- (void)writeBytes:(NSData *)value

Parameters

value

the byte array value to be written

Discussion

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.

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeBytes:offset:length:

Writes a portion of a byte array as a byte array field to the stream message.

- (void)writeBytes:(NSData *)value offset:(int)offset length:(int)length

Parameters

value

the byte array value to be written

offset

the initial offset within the byte array

length

the number of bytes to use

Discussion

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.

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeChar:

Writes a char to the stream message.

- (void)writeChar:(unichar)value

Parameters

value

the char value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeDouble:

Writes a double to the stream message.

- (void)writeDouble:(double)value

Parameters

value

the double value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeFloat:

Writes a float to the stream message.

- (void)writeFloat:(float)value

Parameters

value

the float value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeInt:

Writes an int to the stream message.

- (void)writeInt:(int)value

Parameters

value

the int value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeLong:

Writes a long to the stream message.

- (void)writeLong:(long long)value

Parameters

value

the long value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeObject:

Writes an object to the stream message.

- (void)writeObject:(NSObject *)value

Parameters

value

the object to be written

Discussion

This method works only for the objectified primitive object types (Integer, Double, Long…), String objects, and byte arrays.

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageFormatException

if the object is invalid.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeShort:

Writes a short to the stream message.

- (void)writeShort:(short)value

Parameters

value

the short value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h

writeString:

Writes a String to the stream message.

- (void)writeString:(NSString *)value

Parameters

value

the String value to be written

Exceptions

KMJMSException

if the JMS provider fails to write the message due to some internal error.

KMMessageNotWriteableException

if the message is in read-only mode.

Declared In

KMStreamMessage.h