javax.jms: public interface: StreamMessage

javax.jms
public interface: StreamMessage [javadoc | source]

All Implemented Interfaces:
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.

Also see:

javax.jms.Session#createStreamMessage()

javax.jms.BytesMessage

javax.jms.MapMessage

javax.jms.Message

javax.jms.ObjectMessage

javax.jms.TextMessage

Method from javax.jms.StreamMessage Summary:
readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readInt, readLong, readObject, readShort, readString, reset, writeBoolean, writeByte, writeBytes, writeBytes, writeChar, writeDouble, writeFloat, writeInt, writeLong, writeObject, writeShort, writeString

Method from javax.jms.StreamMessage Detail:
public boolean readBoolean() throws JMSException Reads a `boolean` from the stream message.
public byte readByte() throws JMSException Reads a `byte` value from the stream message.
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 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.
public char readChar() throws JMSException Reads a Unicode character value from the stream message.
public double readDouble() throws JMSException Reads a `double` from the stream message.
public float readFloat() throws JMSException Reads a `float` from the stream message.
public int readInt() throws JMSException Reads a 32-bit integer from the stream message.
public long readLong() throws JMSException Reads a 64-bit integer from the stream message.
public 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`.
public short readShort() throws JMSException Reads a 16-bit integer from the stream message.
public String readString() throws JMSException Reads a `String` from the stream message.
public void reset() throws JMSException Puts the message body in read-only mode and repositions the stream to the beginning.
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`.
public void writeByte(byte value) throws JMSException Writes a `byte` to the stream message.
public 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.
public 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.
public void writeChar(char value) throws JMSException Writes a `char` to the stream message.
public void writeDouble(double value) throws JMSException Writes a `double` to the stream message.
public void writeFloat(float value) throws JMSException Writes a `float` to the stream message.
public void writeInt(int value) throws JMSException Writes an `int` to the stream message.
public void writeLong(long value) throws JMSException Writes a `long` to the stream message.
public 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.
public void writeShort(short value) throws JMSException Writes a `short` to the stream message.
public void writeString(String value) throws JMSException Writes a `String` to the stream message.