protocol.java

用于移动设备上的java虚拟机源代码

    public int getBaudRate() {
	return baud;
    }

    /** 
     * Sets the baudrate for the serial port connection.
     * If the requested <code>baudrate</code> is not supported 
     * on the platform, then the system MAY use an alternate valid setting.
     * The alternate value can be accessed using the 
     * <code>getBaudRate</code> method.
     * @param baudrate the baudrate for the connection
     * @return the previous baudrate of the connection
     * @see #getBaudRate
     */
    public int setBaudRate(int baudrate) {
	int temp = baud;

	/*
	 * If the baudrate is not supported, select one
	 * that is allowed.
	 */
	if (baudrate < 299) {
            baudrate = 110;
        } else if (baudrate < 599) {
            baudrate = 300;
        } else if (baudrate < 1199) {
            baudrate = 600;
        } else if (baudrate < 2399) {
            baudrate = 1200;
        } else if (baudrate < 4799) {
            baudrate = 2400;
        } else if (baudrate < 9599) {
            baudrate = 4800;
        } else if (baudrate < 14399) {
            baudrate = 9600;
        } else if (baudrate < 19199) {
            baudrate = 14400;
        } else if (baudrate < 38399) {
            baudrate = 19200;
        } else if (baudrate < 55999) {
            baudrate = 38400;
        } else if (baudrate < 57599) {
            baudrate = 56000;
        } else if (baudrate < 115199) {
            baudrate = 57600;
        } else if (baudrate < 127999) {
            baudrate = 115200;
        } else if (baudrate < 255999) {
            baudrate = 128000;
        } else {
            baudrate = 256000;
	}
	try {
	    /* Set the new baudrate. */ 
	    native_configurePort(handle, baudrate,
				 bbc|stop|parity|rts|cts);
	    /* If successful, update the local baud variable. */
	    baud = baudrate;
	} catch (IOException ioe) {
	    // NYI - could not set baudrate as requested.
	}
	return temp;
    }
      
    /**
     * Close the native serial port.
     *
     * @exception  IOException  if an I/O error occurs.
     */
    protected void disconnect() throws IOException {
	try {
	    native_close(handle);
	} finally {
	    /* Reset handle to prevent resgistered cleanup close. */
	    handle = -1;
	}
    }

    /**
     * Reads up to <code>len</code> bytes of data from the input stream into
     * an array of bytes, blocks until at least one byte is available,
     * if blocking is turned on.
     * Sets the <code>eof</code> field of the connection when the native read
     * returns -1.
     * <p>
     * Polling the native code is done here to avoid the need for
     * asynchronous native methods to be written. Not all implementations
     * work this way (they block in the native code) but the same
     * Java code works for both.
     *
     * @param      b     the buffer into which the data is read
     * @param      off   the start offset in array <code>b</code>
     *                   at which the data is written
     * @param      len   the maximum number of bytes to read
     * @return     the total number of bytes read into the buffer, or
     *             <code>-1</code> if there is no more data because the end of
     *             the stream has been reached
     * @exception  IOException  if an I/O error occurs
     */
    protected int nonBufferedRead(byte b[], int off, int len)
        throws IOException {

        int bytesRead;

        for (;;) {
            try {
                bytesRead = native_readBytes(handle, b, off, len);
            } finally {
                if (iStreams == 0) {
                    throw new InterruptedIOException("Stream closed");
                }
            }

            if (bytesRead == -1) {
                eof = true;
                return -1;
            }

            if (bytesRead != 0 || !blocking) {
                return bytesRead;
            }

            /* Wait a while for I/O to become ready */
            GeneralBase.iowait(); 
        }
    }

    /**
     * Reads up to <code>len</code> bytes of data from the input stream into
     * an array of bytes, but does not block if no bytes available.
     * Sets the <code>eof</code> flag if the end of stream is reached.
     * <p>
     * This is implemented so the <code>available</code> method of
     * <code>BufferedConnectionBaseAdapter</code> will return more than
     * zero if the buffer is empty.
     *
     * @param      b     the buffer into which the data is read
     * @param      off   the start offset in array <code>b</code>
     *                   at which the data is written
     * @param      len   the maximum number of bytes to read
     * @return     the total number of bytes read into the buffer, or
     *             <code>-1</code> if there is no more data because the end of
     *             the stream has been reached
     * @exception  IOException  if an I/O error occurs
     */
    protected int readBytesNonBlocking(byte b[], int off, int len)
            throws IOException {
        int bytesRead;

        try {
            // the native read does not block
            bytesRead = native_readBytes(handle, b, off, len);
        } finally {
            if (iStreams == 0) {
                throw new InterruptedIOException("Stream closed");
            }
        }

        if (bytesRead == -1) {
            eof = true;
        }

        return bytesRead;
    }

    /**
     * Writes <code>len</code> bytes from the specified byte array
     * starting at offset <code>off</code> to this output stream.
     * <p>
     * Polling the native code is in the stream object handed out by
     * our parent helper class. This done to avoid the need for
     * asynchronous native methods to be written. Not all implementations
     * work this way (they block in the native code) but the same
     * Java code works for both.
     *
     * @param      b     the data
     * @param      off   the start offset in the data
     * @param      len   the number of bytes to write
     *
     * @return     number of bytes written
     * @exception  IOException  if an I/O error occurs. In particular,
     *             an <code>IOException</code> is thrown if the output
     *             stream is closed.
     */
    public int writeBytes(byte b[], int off, int len) throws IOException {
        return native_writeBytes(handle, b, off, len);
    }

    /*
     * Real primitive methods
     */

    /**
     * Open a serial port by logical number.
     *
     * @param port logical number of the port 0 being the first
     * @param baud baud rate to set the port at
     * @param flags options for the serial port
     *
     * @return handle to a native serial port
     *
     * @exception  IOException  if an I/O error occurs.
     */
    private static native int native_openByNumber(int port, int baud,
        int flags) throws IOException;

    /**
     * Open a serial port by system dependent device name.
     *
     * @param name device name of the port
     * @param baud baud rate to set the port at
     * @param flags options for the serial port
     *
     * @return handle to a native serial port
     *
     * @exception  IOException  if an I/O error occurs.
     */
    private static native int native_openByName(String name, int baud,
        int flags) throws IOException;

    /**
     * Configure a serial port optional parameters.
     *
     * @param port device port returned from open
     * @param baud baud rate to set the port at
     * @param flags options for the serial port
     *
     * @exception  IOException  if an I/O error occurs
     */
    private static native void native_configurePort(int port, int baud,
        int flags) throws IOException;

    /**
     * Close a serial port.
     *
     * @param hPort handle to a native serial port
     *
     * @exception  IOException  if an I/O error occurs
     */
    private static native void native_close(int hPort) throws IOException;

    /** Register this object's native cleanup function. */
    private native void registerCleanup();

    /**
     * Read from a serial port without blocking.
     *
     * @param hPort handle to a native serial port
     * @param b I/O buffer
     * @param off starting offset for data
     * @param len length of data
     *
     * @return number of bytes read
     *
     * @exception  IOException  if an I/O error occurs
     */
    private static native int native_readBytes(int hPort, byte b[], int off,
        int len) throws IOException;

    /**
     * Write to a serial port without blocking.
     *
     * @param hPort handle to a native serial port
     * @param b I/O buffer
     * @param off starting offset for data
     * @param len length of data
     *
     * @return number of bytes that were written
     *
     * @exception  IOException  if an I/O error occurs.
     */
    private static native int native_writeBytes(int hPort, byte b[], int off,
        int len) throws IOException;

    /**
     * Native finalizer.
     */
    private native void finalize();
}