tcptemperaturesensor.java

这是一个以JAVA编写的程序,本人还没有试过,是一个简单的温度控制系统

        }
        
        final int RETRY_COUNT = 20;
        
        protected void execute() throws Throwable {
        
            int retryCount = RETRY_COUNT;
            
            while ( retryCount > 0 ) {
            
                while ( isEnabled() ) {
                
                    if ( br == null ) {
                    
                        // This means that the connection reestablishment
                        // attempt has just failed
                        
                        break;
                    }
                    
                    try {
                
                        String line = br.readLine();
                        
                        if ( line == null ) {
                        
                            complain(LOG_ERR, CH_LISTENER, "Socket broken, exiting loop");
                            
                            processError("Connection Lost");
                            break;
                        }
                        
                        StringTokenizer st = new StringTokenizer(line, " ");
                        
                        // There is a few reserved words:
                        //
                        //	D	Data
                        //	E	Error
                        //	+	Arrival
                        //	-	Departure
                        //
                        // If the first word (as in 'whitespace delimited
                        // sequence') is reserved, then the parsing logic
                        // changes. Otherwise, we process it just as before.
                        
                        String header = st.nextToken();
                        
                        if ( "E".equals(header) ) {
                        
                            processError(line.substring(2));

                        } else if ( "+".equals(header) ) {
                        
                            processArrival(st.nextToken());

                        } else if ( "-".equals(header) ) {
                        
                            processDeparture(st.nextToken());

                        } else if ( "D".equals(header) ) {
                        
                            processData(line.substring(2));
                            
                        } else {
                        
                            processData(line);
                        }

                    } catch ( SSLException sslex ) {
                    
                        if ( sslex.getMessage() != null ) {
                        
                            if ( sslex.getMessage().equals("Unrecognized SSL message, plaintext connection?") ) {
                            
                                // Let's retry as insecure
                                
                                complain(LOG_WARNING, CH_LISTENER, "Can't establish secure connection to "
                                                               + remoteHost + ":" + remotePort
                                                               + ", other end seems to be plaintext");
                                complain(LOG_WARNING, CH_LISTENER, "Reverting to insecure connection");
                                
                                socket = null;
                                br = null;
                                
                                secure = false;
                                break;
                            }

                        } else {
                        
                            // I don't know what it is
                            
                            throw sslex;
                        }
                    }
                    
                }
                
                if ( !isEnabled() ) {
                
                    return;
                }
                
                // If we're here, it means that the socket has gone bad and
                // retryCount is positive. Let's try to reestablish the
                // connection.
                
                Thread.sleep(10000);
                
                try {
                
                    socket = new Socket(remoteHost, remotePort);
                    br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    
                    retryCount = RETRY_COUNT;
                    
                    complain(LOG_NOTICE, CH_LISTENER, "Connection reestablished");
                    
                } catch ( IOException ioex ) {
                
                    complain(LOG_NOTICE, CH_LISTENER, "Can't reestablish the connection, "
                    	+ retryCount
                    	+ " retries left, cause:", ioex);
                    
                    socket = null;
                    br = null;
                }
                
                retryCount--;
            }
            
            complain(LOG_CRIT, CH_LISTENER, "Retry count exceeded, sensor server unavailable, terminating");
        }
        
        private void processData(String line) {
        
            StringTokenizer st = new StringTokenizer(line, " ");
        
            String address = st.nextToken();
            String temp = st.nextToken();
            
            TcpTemperatureSensor s = (TcpTemperatureSensor)listenerMap.get(address);
            
            if ( s == null ) {
            
                if ( !warningList.contains(address) ) {
                
                    complain(LOG_WARNING, CH_LISTENER, "No listener for " + address);
                    warningList.add(address);
                }
            
            } else {
            
                s.currentTemperatureChanged(null, new Double(Double.parseDouble(temp)));
            }
        }
        
        private void processError(String line) {
        
            // VT: FIXME: This may not be associated with a sensor address
            // (such as 1-Wire short circuit). Therefore, it may be
            // necessary to broadcast such a condition to all the sensors.
            
            // VT: NOTE: However, it may so happen that the error is indeed
            // related to an individual sensor, so let's try to process it
            // as usual.
        
            //complain(LOG_WARNING, CH_LISTENER, "Error reported: " + line);
            
            StringTokenizer st = new StringTokenizer(line, " ");
            String address = st.nextToken();
            String error = line.substring(address.length() + 1);

            TcpTemperatureSensor s = (TcpTemperatureSensor)listenerMap.get(address);
            
            if ( s == null ) {
            
                error = line;
            
                complain(LOG_WARNING, CH_LISTENER, "General error: " + error);
                
                for ( Iterator i = listenerMap.keySet().iterator(); i.hasNext(); ) {
                
                    address = i.next().toString();
                    s = (TcpTemperatureSensor)listenerMap.get(address);
                    
                    s.currentTemperatureChanged(null, error);
                }
            
            } else {
            
                s.currentTemperatureChanged(null, error);
            }
        }

        private void processArrival(String address) {
        
            // VT: NOTE: There's nothing to process, really. To the actual
            // consumers, the arrival itself doesn't mean anything at all
            // unless the sensor starts producing data - and this case is
            // already handled.
        
            complain(LOG_NOTICE, CH_LISTENER, "Sensor arrived: " + address);
        }
        
        private void processDeparture(String address) {
        
            complain(LOG_WARNING, CH_LISTENER, "Sensor departed: " + address);

            TcpTemperatureSensor s = (TcpTemperatureSensor)listenerMap.get(address);
            
            if ( s == null ) {
            
                if ( !warningList.contains(address) ) {
                
                    complain(LOG_WARNING, CH_LISTENER, "No listener for " + address);
                    warningList.add(address);
                }
            
            } else {
            
                // VT: NOTE: Let the consumer worry about handling the
                // momentary lapses - the control logic doesn't belong at
                // this level
            
                s.currentTemperatureChanged(null, "Sensor Departed");
            }
        }

        protected void shutdown(Throwable cause) throws Throwable {
        
        }
        
        public void addListener(TcpTemperatureSensor l) {
        
            listenerMap.put(l.getAddress(), l);
        }
    }
}