/**
* Copyright (c) 2010-2016 by the respective copyright holders.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*/
package org.openhab.binding.ebus.internal.connection;
import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.openhab.binding.ebus.internal.EBusTelegram;
import org.openhab.binding.ebus.internal.utils.EBusUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* @author Christian Sowada
* @since 1.7.0
*/
public abstract class AbstractEBusConnector extends Thread {
private static final Logger logger = LoggerFactory.getLogger(AbstractEBusConnector.class);
/** the list for listeners */
private final List<EBusConnectorEventListener> listeners = new ArrayList<EBusConnectorEventListener>();
/** serial receive buffer */
protected final ByteBuffer inputBuffer = ByteBuffer.allocate(100);
/** counts the re-connection tries */
protected int reConnectCounter = 0;
/** The thread pool to execute events without blocking */
protected ExecutorService threadPool;
/** The nano time for the last received byte from inputStream */
// protected long lastReceiveTime = 0;
/**
* Constructor
*/
public AbstractEBusConnector() {
super("eBUS Connection Thread");
this.setDaemon(true);
}
/**
* Connects the connector to its backend system. It's important
* to connect before start the thread.
*
* @return
* @throws IOException
*/
protected boolean connect() throws IOException {
inputBuffer.clear();
return true;
}
/**
* Disconnects the connector from its backend system.
*
* @return
* @throws IOException
*/
protected boolean disconnect() throws IOException {
// nothing
return true;
}
/**
* Add an eBus listener to receive valid eBus telegrams
*
* @param listener
*/
public void addEBusEventListener(EBusConnectorEventListener listener) {
listeners.add(listener);
}
/**
* Remove an eBus listener
*
* @param listener
* @return
*/
public boolean removeEBusEventListener(EBusConnectorEventListener listener) {
return listeners.remove(listener);
}
/**
* Reconnect to the eBus up to 50 times. Connection can be lost by restart
* heating system etc. Warning, can cause an file handler issue
* on Linux (Windows not tested!) with serial connections.
*
* @throws IOException
* @throws InterruptedException
*/
protected void reconnect() throws IOException, InterruptedException {
if (disconnect()) {
if (!connect()) {
if (reConnectCounter < 50) {
reConnectCounter++;
} else {
logger.error(
"Stop eBus connector after 50 tries, please check eBus adapter and restart eBus binding.");
reConnectCounter = -1;
}
int sleepTime = reConnectCounter > 24 ? 30 : 5;
logger.warn("Unable to connect to eBus, retry in {} seconds ...", sleepTime);
Thread.sleep(sleepTime * 1000);
} else {
reConnectCounter = 0;
}
}
}
/*
* (non-Javadoc)
*
* @see java.lang.Thread#run()
*/
@Override
public void run() {
// create new thread pool to send received telegrams
threadPool = Executors.newCachedThreadPool(new WorkerThreadFactory("ebus-send-receive"));
int read = -1;
// loop until interrupt or reconnector count is -1 (to many retries)
while (!isInterrupted() || reConnectCounter == -1) {
try {
if (!isConnected()) {
reconnect();
} else {
// read byte from connector
read = readByte(false);
// lastReceiveTime = System.nanoTime();
if (read == -1) {
logger.debug("eBUS read timeout occured, no data on bus ...");
} else {
byte receivedByte = (byte) (read & 0xFF);
// write received byte to input buffer
inputBuffer.put(receivedByte);
// the 0xAA byte is a end of a packet
if (receivedByte == EBusTelegram.SYN) {
// check if the buffer is empty and ready for
// sending data
try {
onEBusSyncReceived(isReceiveBufferEmpty());
} catch (Exception e) {
logger.error("Error while processing event sync received!", e);
}
}
}
}
} catch (IOException e) {
logger.error("An IO exception has occured! Try to reconnect eBus connector ...", e);
try {
reconnect();
} catch (IOException e1) {
logger.error(e.toString(), e1);
} catch (InterruptedException e1) {
logger.error(e.toString(), e1);
}
} catch (BufferOverflowException e) {
logger.error(
"eBUS telegram buffer overflow - not enough sync bytes received! Try to adjust eBus adapter.");
inputBuffer.clear();
} catch (InterruptedException e) {
logger.error(e.toString(), e);
Thread.currentThread().interrupt();
inputBuffer.clear();
} catch (Exception e) {
logger.error(e.toString(), e);
inputBuffer.clear();
}
}
// *******************************
// ** end of thread **
// *******************************
// shutdown threadpool
if (threadPool != null && !threadPool.isShutdown()) {
threadPool.shutdownNow();
try {
// wait up to 10sec. for the thread pool
threadPool.awaitTermination(10, TimeUnit.SECONDS);
} catch (InterruptedException e) {
}
}
// disconnect the connector e.g. close serial port
try {
disconnect();
} catch (IOException e) {
logger.error(e.toString(), e);
}
}
/**
* Called event if a SYN packet has been received
*
* @throws IOException
*/
protected void onEBusSyncReceived(boolean allowSend) throws IOException {
if (inputBuffer.position() == 1 && inputBuffer.get(0) == EBusTelegram.SYN) {
logger.trace("Auto-SYN byte received");
} else if (inputBuffer.position() == 2 && inputBuffer.get(0) == EBusTelegram.SYN) {
logger.warn("Collision on eBUS detected (SYN DATA SYNC Sequence) ...");
} else if (inputBuffer.position() < 5) {
logger.trace("Telegram too small, skip! Buffer: {}", EBusUtils.toHexDumpString(inputBuffer));
} else {
byte[] receivedTelegram = Arrays.copyOf(inputBuffer.array(), inputBuffer.position());
// execute event
onEBusTelegramReceived(receivedTelegram);
}
// reset receive buffer
inputBuffer.clear();
}
/**
* Called if a valid eBus telegram was received. Send to event
* listeners via thread pool to prevent blocking.
*
* @param telegram
*/
protected void onEBusTelegramReceived(final byte[] receivedTelegram) {
if (threadPool == null) {
logger.warn("ThreadPool not ready!");
return;
}
threadPool.execute(new Runnable() {
@Override
public void run() {
final EBusTelegram telegram = EBusUtils.processEBusData(receivedTelegram);
if (telegram != null) {
for (EBusConnectorEventListener listener : listeners) {
listener.onTelegramReceived(telegram);
}
} else {
logger.debug("Received telegram was invalid, skip!");
}
}
});
}
/**
* Reads one byte from backend
*
* @return
* @throws IOException
*/
protected abstract int readByte(boolean lowLatency) throws IOException;
/**
* Returns true if the receive buffer is empty, in this case the line is free to send
*
* @return
* @throws IOException
*/
protected abstract boolean isReceiveBufferEmpty() throws IOException;
/**
* Returns if the connection is already connected to the backend
*
* @return
*/
protected abstract boolean isConnected();
}