package javax.jms;

/** A <CODE>StreamMessage</CODE> 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 <CODE>Message</CODE> interface
 * and adds a stream message body. Its methods are based largely on those
 * found in <CODE>java.io.DataInputStream</CODE> and
 * <CODE>java.io.DataOutputStream</CODE>.
 *
 * <P>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 <CODE>StreamMessage.writeInt(6)</CODE> is
 * equivalent to <CODE>StreamMessage.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 body 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.
 *
 * <P><CODE>StreamMessage</CODE> objects support the following conversion 
 * table. The marked cases must be supported. The unmarked cases must throw a 
 * <CODE>JMSException</CODE>. The <CODE>String</CODE>-to-primitive conversions 
 * may throw a runtime exception if the primitive's <CODE>valueOf()</CODE> 
 * method does not accept it as a valid <CODE>String</CODE> representation of 
 * the primitive.
 *
 * <P>A value written as the row type can be read as the column type.
 *
 * <PRE>
 * |        | 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
 * |----------------------------------------------------------------------
 * </PRE>
 *
 * <P>Attempting to read a null value as a primitive type must be treated
 * as calling the primitive's corresponding <code>valueOf(String)</code> 
 * conversion method with a null value. Since <code>char</code> does not 
 * support a <code>String</code> conversion, attempting to read a null value 
 * as a <code>char</code> must throw a <code>NullPointerException</code>.
 *
 * @see         javax.jms.Session#createStreamMessage()
 * @see         javax.jms.BytesMessage
 * @see         javax.jms.MapMessage
 * @see         javax.jms.Message
 * @see         javax.jms.ObjectMessage
 * @see         javax.jms.TextMessage
 */

public interface StreamMessage extends Message
{

   /** Reads a <code>boolean</code> from the stream message.
    *
    * @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 message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   boolean readBoolean() throws JMSException;

   /** Reads a <code>byte</code> value from the stream message.
    *
    * @return the next byte from the stream message as a 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 message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   byte readByte() throws JMSException;

   /** Reads a 16-bit integer from the stream message.
    *
    * @return a 16-bit integer from the stream message
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   short readShort() throws JMSException;

   /** Reads a Unicode character value from the stream message.
    *
    * @return a Unicode character from the stream message
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid      
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   char readChar() throws JMSException;

   /** Reads a 32-bit integer from the stream message.
    *
    * @return a 32-bit integer value from the stream message, 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 message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   int readInt() throws JMSException;

   /** Reads a 64-bit integer from the stream message.
    *
    * @return a 64-bit integer value from the stream message, 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 message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   long readLong() throws JMSException;

   /** Reads a <code>float</code> from the stream message.
    *
    * @return a <code>float</code> value from the stream message
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   float readFloat() throws JMSException;

   /** Reads a <code>double</code> from the stream message.
    *
    * @return a <code>double</code> value from the stream message
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   double readDouble() throws JMSException;

   /** Reads a <CODE>String</CODE> from the stream message.
    *
    * @return a Unicode string from the stream message
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    */

   String readString() throws JMSException;

   /** Reads a byte array field from the stream message into the 
    * specified <CODE>byte[]</CODE> object (the read buffer). 
    * 
    * <P>To read the field value, <CODE>readBytes</CODE> 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.
    * 
    * <P>If <CODE>readBytes</CODE> returns a value equal to the length of the 
    * buffer, a subsequent <CODE>readBytes</CODE> call must be made. If there 
    * are no more bytes to be read, this call returns -1.
    * 
    * <P>If the byte array field value is null, <CODE>readBytes</CODE> 
    * returns -1.
    *
    * <P>If the byte array field value is empty, <CODE>readBytes</CODE> 
    * returns 0.
    * 
    * <P>Once the first <CODE>readBytes</CODE> call on a <CODE>byte[]</CODE>
    * 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 <CODE>MessageFormatException</CODE>.
    * 
    * <P>To read the byte field value into a new <CODE>byte[]</CODE> object, 
    * use the <CODE>readObject</CODE> method.
    *
    * @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 byte field has been 
    * reached
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    * 
    * @see #readObject()
    */

   int readBytes(byte[] value) throws JMSException;

   /** Reads an object from the stream message.
    *
    * <P>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
    * <CODE>writeObject</CODE> method call, or its equivalent primitive
    * <CODE>write<I>type</I></CODE> method.
    *  
    * <P>Note that byte values are returned as <CODE>byte[]</CODE>, not 
    * <CODE>Byte[]</CODE>.
    *
    * <P>An attempt to call <CODE>readObject</CODE> to read a byte field 
    * value into a new <CODE>byte[]</CODE> object before the full value of the
    * byte field has been read will throw a 
    * <CODE>MessageFormatException</CODE>.
    *
    * @return a Java object from the stream message, in objectified
    * format (for example, if the object was written as an <CODE>int</CODE>, 
    * an <CODE>Integer</CODE> is returned)
    *
    * @exception JMSException if the JMS provider fails to read the message
    *                         due to some internal error.
    * @exception MessageEOFException if unexpected end of message stream has
    *                                been reached.     
    * @exception MessageFormatException if this type conversion is invalid.
    * @exception MessageNotReadableException if the message is in write-only 
    *                                        mode.
    * 
    * @see #readBytes(byte[] value)
    */

   Object readObject() throws JMSException;

   /** Writes a <code>boolean</code> to the stream message.
    * 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.
    */

   void writeBoolean(boolean value) throws JMSException;

   /** Writes a <code>byte</code> to the stream message.
    *
    * @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.
    */

   void writeByte(byte value) throws JMSException;

   /** Writes a <code>short</code> to the stream message.
    *
    * @param value the <code>short</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.
    */

   void writeShort(short value) throws JMSException;

   /** Writes a <code>char</code> to the stream message.
    *
    * @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.
    */

   void writeChar(char value) throws JMSException;

   /** Writes an <code>int</code> to the stream message.
    *
    * @param value the <code>int</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.
    */

   void writeInt(int value) throws JMSException;

   /** Writes a <code>long</code> to the stream message.
    *
    * @param value the <code>long</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.
    */

   void writeLong(long value) throws JMSException;

   /** Writes a <code>float</code> to the stream message.
    *
    * @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.
    */

   void writeFloat(float value) throws JMSException;

   /** Writes a <code>double</code> to the stream message.
    *
    * @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.
    */

   void writeDouble(double value) throws JMSException;

   /** Writes a <code>String</code> to the stream message.
    *
    * @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.
    */

   void writeString(String value) throws JMSException;

   /** Writes a byte array field to the stream message.
    *
    * <P>The byte array <code>value</code> 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.
    * 
    * @param value the byte array 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.
    */

   void writeBytes(byte[] value) throws JMSException;

   /** Writes a portion of a byte array as a byte array field to the stream 
    * message.
    *  
    * <P>The a portion of the byte array <code>value</code> 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.
    *
    * @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.
    */

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

   /** Writes an object to the stream message.
    *
    * <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 Java object to be written
    *
    * @exception JMSException if the JMS provider fails to write the message
    *                         due to some internal error.
    * @exception MessageFormatException if the object is invalid.
    * @exception MessageNotWriteableException if the message is in read-only 
    *                                         mode.
    */

   void writeObject(Object value) throws JMSException;

   /** Puts the message body in read-only mode and repositions the stream
    * 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.
    */

   void reset() throws JMSException;
}
