package javax.jms;

/** A <CODE>BytesMessage</CODE> object is used to send a message containing a 
 * stream of uninterpreted bytes. It inherits from the <CODE>Message</CODE> 
 * interface and adds a bytes
 * message body. The receiver of the message supplies the interpretation
 * of the bytes.
 *
 * <P>The <CODE>BytesMessage</CODE> methods are based largely on those found in
 * <CODE>java.io.DataInputStream</CODE> and
 * <CODE>java.io.DataOutputStream</CODE>.
 *
 * <P>This message type is for client encoding of existing message formats. 
 * If possible, one of the other self-defining message types should be used 
 * instead.
 *
 * <P>Although the JMS API allows the use of message properties with byte 
 * messages, they are typically not used, since the inclusion of properties 
 * may affect the format.
 *
 * <P>The primitive types can be written explicitly using methods
 * for each type. They may also be written generically as objects.
 * For instance, a call to <CODE>BytesMessage.writeInt(6)</CODE> is
 * equivalent to <CODE>BytesMessage.writeObject(new Integer(6))</CODE>.
 * 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.
 *
 * <P>When the message is first created, and when <CODE>clearBody</CODE>
 * is called, the body of the message is in write-only mode. After the 
 * first call to <CODE>reset</CODE> 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 
 * <CODE>reset</CODE> so that the message body is in read-only mode for the client.
 *
 * <P>If <CODE>clearBody</CODE> is called on a message in read-only mode, 
 * the message body is cleared and the message is in write-only mode.
 *
 * <P>If a client attempts to read a message in write-only mode, a 
 * <CODE>MessageNotReadableException</CODE> is thrown.
 *
 * <P>If a client attempts to write a message in read-only mode, a 
 * <CODE>MessageNotWriteableException</CODE> is thrown.
 *
 * @see         javax.jms.Session#createBytesMessage()
 * @see         javax.jms.MapMessage
 * @see         javax.jms.Message
 * @see         javax.jms.ObjectMessage
 * @see         javax.jms.StreamMessage
 * @see         javax.jms.TextMessage
 **/
public interface BytesMessage extends Message
{

   /** Gets the number of bytes of the message body when the message
    * is in read-only mode. The value returned can be used to allocate 
    * a byte array. The value returned is the entire length of the message
    *  body, regardless of where the pointer for reading the message 
    * is currently located.
    * 
    * @return number of bytes in the message 
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageNotReadableException if the message is in write-only
    *                         mode.
    * @since 1.1 
    */
   public long getBodyLength() throws JMSException;

   /** Reads a <code>boolean</code> from the bytes message stream.
    *
    * @return the <code>boolean</code> value read
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public boolean readBoolean() throws JMSException;

   /** Reads a signed 8-bit value from the bytes message stream.
    *
    * @return the next byte from the bytes message stream as a signed 8-bit
    * <code>byte</code>
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public byte readByte() throws JMSException;

   /** Reads an unsigned 8-bit number from the bytes message stream.
    *  
    * @return the next byte from the bytes message stream, interpreted as an
    * unsigned 8-bit number
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public int readUnsignedByte() throws JMSException;

   /** Reads a signed 16-bit number from the bytes message stream.
    *
    * @return the next two bytes from the bytes message stream, interpreted as
    * a signed 16-bit number
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public short readShort() throws JMSException;

   /** Reads an unsigned 16-bit number from the bytes message stream.
    *  
    * @return the next two bytes from the bytes message stream, interpreted as
    * an unsigned 16-bit integer
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public int readUnsignedShort() throws JMSException;

   /** Reads a Unicode character value from the bytes message stream.
    *
    * @return the next two bytes from the bytes message stream as a Unicode
    * character
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public char readChar() throws JMSException;

   /** Reads a signed 32-bit integer from the bytes message stream.
    *
    * @return the next four bytes from the bytes message stream, interpreted
    * as an <code>int</code>
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public int readInt() throws JMSException;

   /** Reads a signed 64-bit integer from the bytes message stream.
    *
    * @return the next eight bytes from the bytes message stream, interpreted
    * as a <code>long</code>
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public long readLong() throws JMSException;

   /** Reads a <code>float</code> from the bytes message stream.
    *
    * @return the next four bytes from the bytes message stream, interpreted
    * as a <code>float</code>
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public float readFloat() throws JMSException;

   /** Reads a <code>double</code> from the bytes message stream.
    *
    * @return the next eight bytes from the bytes message stream, interpreted
    * as a <code>double</code>
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public double readDouble() throws JMSException;

   /** Reads a string that has been encoded using a modified UTF-8
    * format from the bytes message stream.
    *
    * <P>For more information on the UTF-8 format, see "File System Safe
    * UCS Transformation Format (FSS_UTF)", X/Open Preliminary Specification,
    * X/Open Company Ltd., Document Number: P316. This information also
    * appears in ISO/IEC 10646, Annex P.
    *
    * @return a Unicode string from the bytes message stream
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of bytes stream has 
    *                                been reached.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public String readUTF() throws JMSException;

   /** Reads a byte array from the bytes message stream.
    *
    * <P>If the length of array <code>value</code> is less than the number of 
    * bytes remaining to be read from the stream, the array should 
    * be filled. A subsequent call reads the next increment, and so on.
    * 
    * <P>If the number of bytes remaining in the stream is less than the 
    * length of 
    * array <code>value</code>, the bytes should be read into the array. 
    * The return value of the total number of bytes read will be less than
    * the length of the array, indicating that there are no more bytes left 
    * to be read from the stream. The next read of the stream returns -1.
    *
    * @param value the buffer into which the data is read
    *
    * @return the total number of bytes read into the buffer, or -1 if 
    * there is no more data because the end of the stream has been reached
    *
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public int readBytes(byte[] value) throws JMSException;

   /** Reads a portion of the bytes message stream.
    *
    * <P>If the length of array <code>value</code> is less than the number of
    * bytes remaining to be read from the stream, the array should 
    * be filled. A subsequent call reads the next increment, and so on.
    * 
    * <P>If the number of bytes remaining in the stream is less than the 
    * length of 
    * array <code>value</code>, the bytes should be read into the array. 
    * The return value of the total number of bytes read will be less than
    * the length of the array, indicating that there are no more bytes left 
    * to be read from the stream. The next read of the stream returns -1.
    *
    * <p> If <code>length</code> is negative, or
    * <code>length</code> is greater than the length of the array
    * <code>value</code>, then an <code>IndexOutOfBoundsException</code> is
    * thrown. No bytes will be read from the stream for this exception case.
    *  
    * @param value the buffer into which the data is read
    * @param length the number of bytes to read; must be less than or equal to
    *        <code>value.length</code>
    * 
    * @return the total number of bytes read into the buffer, or -1 if
    * there is no more data because the end of the stream has been reached
    *  
    * @exception JMSException if the JMS provider fails to read the message 
    *                         due to some internal error.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */
   public int readBytes(byte[] value, int length) throws JMSException;

   /** Writes a <code>boolean</code> to the bytes message stream as a 1-byte 
    * value.
    * The value <code>true</code> is written as the value 
    * <code>(byte)1</code>; the value <code>false</code> is written as 
    * the value <code>(byte)0</code>.
    *
    * @param value the <code>boolean</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeBoolean(boolean value) throws JMSException;

   /** Writes a <code>byte</code> to the bytes message stream as a 1-byte 
    * value.
    *
    * @param value the <code>byte</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeByte(byte value) throws JMSException;

   /** Writes a <code>short</code> to the bytes message stream as two bytes,
    * high byte first.
    *
    * @param value the <code>short</code> to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeShort(short value) throws JMSException;

   /** Writes a <code>char</code> to the bytes message stream as a 2-byte
    * value, high byte first.
    *
    * @param value the <code>char</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeChar(char value) throws JMSException;

   /** Writes an <code>int</code> to the bytes message stream as four bytes, 
    * high byte first.
    *
    * @param value the <code>int</code> to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeInt(int value) throws JMSException;

   /** Writes a <code>long</code> to the bytes message stream as eight bytes, 
    * high byte first.
    *
    * @param value the <code>long</code> to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeLong(long value) throws JMSException;

   /** Converts the <code>float</code> argument to an <code>int</code> using 
    * the
    * <code>floatToIntBits</code> method in class <code>Float</code>,
    * and then writes that <code>int</code> value to the bytes message
    * stream as a 4-byte quantity, high byte first.
    *
    * @param value the <code>float</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeFloat(float value) throws JMSException;

   /** Converts the <code>double</code> argument to a <code>long</code> using 
    * the
    * <code>doubleToLongBits</code> method in class <code>Double</code>,
    * and then writes that <code>long</code> value to the bytes message
    * stream as an 8-byte quantity, high byte first.
    *
    * @param value the <code>double</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeDouble(double value) throws JMSException;

   /** Writes a string to the bytes message stream using UTF-8 encoding in a 
    * machine-independent manner.
    *
    * <P>For more information on the UTF-8 format, see "File System Safe 
    * UCS Transformation Format (FSS_UTF)", X/Open Preliminary Specification,       
    * X/Open Company Ltd., Document Number: P316. This information also 
    * appears in ISO/IEC 10646, Annex P. 
    *
    * @param value the <code>String</code> value to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeUTF(String value) throws JMSException;

   /** Writes a byte array to the bytes message stream.
    *
    * @param value the byte array to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeBytes(byte[] value) throws JMSException;

   /** Writes a portion of a byte array to the bytes message stream.
    *  
    * @param value the byte array value to be written
    * @param offset the initial offset within the byte array
    * @param length the number of bytes to use
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */
   public void writeBytes(byte[] value, int offset, int length) throws JMSException;

   /** Writes an object to the bytes message stream.
    *
    * <P>This method works only for the objectified primitive
    * object types (<code>Integer</code>, <code>Double</code>, 
    * <code>Long</code>&nbsp;...), <code>String</code> objects, and byte 
    * arrays.
    *
    * @param value the object in the Java programming language ("Java 
    *              object") to be written; it must not be null
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageFormatException if the object is of an invalid type.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    * @exception java.lang.NullPointerException if the parameter 
    *                                           <code>value</code> is null.
    */
   public void writeObject(Object value) throws JMSException;

   /** Puts the message body in read-only mode and repositions the stream of 
    * bytes to the beginning.
    *  
    * @exception JMSException if the JMS provider fails to reset the message
    *                         due to some internal error.
    * @exception MessageFormatException if the message has an invalid
    *                         format.
    */
   public void reset() throws JMSException;
}
