javax.bluetooth.L2CAPConnection Maven / Gradle / Ivy
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/**
* Java docs licensed under the Apache License, Version 2.0
* http://www.apache.org/licenses/LICENSE-2.0
* (c) Copyright 2001, 2002 Motorola, Inc. ALL RIGHTS RESERVED.
*
*
* @version $Id: L2CAPConnection.java 1379 2007-10-13 02:00:43Z vlads $
*/
package javax.bluetooth;
import java.io.IOException;
import javax.microedition.io.Connection;
/**
* The L2CAPConnection interface represents a
* connection-oriented L2CAP channel. This interface is to be
* used as part of the CLDC Generic Connection Framework.
*
* To create a client connection, the protocol is btl2cap.
* The target is the combination of the address
* of the Bluetooth device to connect to and the Protocol
* Service Multiplexor (PSM) of the service.
* The PSM value is used by the
* L2CAP to determine which higher level protocol or application is the
* recipient of the messages the layer receives.
*
* The parameters defined specific to L2CAP are ReceiveMTU (Maximum
* Transmission Unit (MTU)) and TransmitMTU. The ReceiveMTU and TransmitMTU
* parameters are optional. ReceiveMTU
* specifies the maximum payload size this connection can accept, and
* TransmitMTU specifies the maximum payload size this connection can
* send. An example of a valid L2CAP client connection string is:
* btl2cap://0050CD00321B:1003;ReceiveMTU=512;TransmitMTU=512
*
* @version 1.0 February 11, 2002
*/
public interface L2CAPConnection extends Connection {
/**
* Default MTU value for connection-oriented channels
* is 672 bytes.
*
* The value of DEFAULT_MTU is 0x02A0 (672).
*/
public static final int DEFAULT_MTU = 672;
/**
* Minimum MTU value for connection-oriented channels
* is 48 bytes.
*
* The value of MINIMUM_MTU is 0x30 (48).
*/
public static final int MINIMUM_MTU = 48;
/**
* Returns the MTU that the remote device supports. This value
* is obtained after the connection has been configured. If the
* application had specified TransmitMTU in the Connector.open()
* string then this value should be equal to that. If the application did
* not specify any TransmitMTU, then this value should be less than or
* equal to the ReceiveMTU the remote device advertised during
* channel configuration.
*
* @return the maximum number of bytes that can be sent in a single call to
* send() without losing any data
*
* @exception IOException if the connection is closed
*/
public int getTransmitMTU() throws IOException;
/**
* Returns the ReceiveMTU that the connection supports. If the
* connection string did not specify a ReceiveMTU, the value returned will be
* less than or equal to the DEFAULT_MTU. Also, if the connection
* string did specify an MTU, this value will be less than or equal to the
* value specified in the connection string.
*
* @return the maximum number of bytes that can be read in a single call
* to receive()
*
* @exception IOException if the connection is closed
*
*/
public int getReceiveMTU() throws IOException;
/**
* Requests that data be sent to the remote device. The TransmitMTU
* determines the amount of data that can be successfully sent in
* a single send operation. If the size of data is
* greater than the TransmitMTU, then only the first TransmitMTU bytes
* of the packet are sent, and the rest will be discarded. If
* data is of length 0, an empty L2CAP packet will be sent.
*
* @param data data to be sent
*
* @exception IOException if data cannot be sent successfully
* or if the connection is closed
*
* @exception NullPointerException if the data is
* null
*/
public void send(byte[] data) throws IOException;
/**
* Reads a packet of data. The amount of data received in
* this operation is related to the value of ReceiveMTU. If
* the size of inBuf is greater than or equal to ReceiveMTU, then
* no data will be lost. Unlike read() on an
* java.io.InputStream, if the size of inBuf is
* smaller than ReceiveMTU, then the portion of the L2CAP payload that will
* fit into inBuf will be placed in inBuf, the
* rest will be discarded. If the application is aware of the number of
* bytes (less than ReceiveMTU) it will receive in any transaction, then
* the size of inBuf can be less than ReceiveMTU and no data
* will be lost. If inBuf is of length 0, all data sent in
* one packet is lost unless the length of the packet is 0.
*
* @param inBuf byte array to store the received data
*
* @return the actual number of bytes read; 0 if a zero length packet is
* received; 0 if inBuf length is zero
*
* @exception IOException if an I/O error occurs or the connection has been
* closed
*
* @exception InterruptedIOException if the request timed out
*
* @exception NullPointerException if inBuf is null
*/
public int receive(byte[] inBuf) throws IOException;
/**
* Determines if there is a packet that can be read via a call to
* receive(). If true, a call to
* receive() will not block the application.
*
* @see #receive
*
* @return true if there is data to read;
* false if there is no data to read
*
* @exception IOException if the connection is closed
*
*/
public boolean ready() throws IOException;
}