JMSStreamMessage

public class JMSStreamMessage
extends JMSMessage
implements StreamMessage
java.lang.Object
   |
   +----com.ibm.jms.JMSMessage
           |
           +----com.ibm.jms.JMSStreamMessage
          

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.

Methods

clearBody

public void clearBody() throws JMSException;

Clears the message body. All other parts of the message are left untouched.

Exceptions

readBoolean

public boolean readBoolean() throws JMSException;

Reads a boolean from the stream message.

Returns
Exceptions

readByte

public byte readByte() throws JMSException;

Reads a byte value from the stream message.

Returns
Exceptions

readBytes

public 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 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.

Parameters
Returns
Exceptions

readChar

public char readChar() throws JMSException;

Reads a Unicode character value from the stream message.

Returns
Exceptions

readDouble

public double readDouble() throws JMSException;

Reads a double from the stream message.

Returns
Exceptions

readFloat

public float readFloat() throws JMSException;

Reads a float from the stream message.

Returns
Exceptions

readInt

public int readInt() throws JMSException;

Reads a 32-bit integer from the stream message.

Returns
Exceptions

readLong

public long readLong() throws JMSException;

Reads a 64-bit integer from the stream message.

Returns
Exceptions

readObject

public Object readObject() throws 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.

Returns
Exceptions

readShort

public short readShort() throws JMSException;

Reads a 16-bit integer from the stream message.

Returns
Exceptions

readString

public String readString() throws JMSException;

Reads in a String from the stream message.

Returns
Exceptions

reset

public void reset() throws JMSException;

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

Exceptions

toString

public String toString();

Gets a String containing a formatted version of the Message.

Returns

writeBoolean

public 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
Exceptions

writeByte

public void writeByte(byte value) throws JMSException;

Writes a byte to the stream message.

Parameters
Exceptions

writeBytes

public void writeBytes(byte[] value) throws JMSException;

Writes a byte array to the stream message.

Parameters
Exceptions

writeBytes

public void writeBytes(byte[] value, int offset, int length) 
              throws JMSException;

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

Parameters
Exceptions

writeChar

public void writeChar(char value) throws JMSException;

Writes a char to the stream message.

Parameters
Exceptions

writeDouble

public void writeDouble(double value) throws JMSException;

Writes a double to the stream message.

Parameters
Exceptions

writeFloat

public void writeFloat(float value) throws JMSException;

Writes a float to the stream message.

Parameters
Exceptions

writeInt

public void writeInt(int value) throws JMSException;

Writes an int to the stream message.

Parameters
Exceptions

writeLong

public void writeLong(long value) throws JMSException;

Writes a long to the stream message.

Parameters
Exceptions

writeObject

public void writeObject(Object value) throws 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.

Parameters
Exceptions

writeShort

public void writeShort(short value) throws JMSException;

Write a short to the stream message.

Parameters
Exceptions

writeString

public void writeString(String value) throws JMSException;

Writes a String to the stream message.

Parameters
Exceptions