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Calimero, a free KNX network library
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/*
Calimero 2 - A library for KNX network access
Copyright (c) 2015, 2024 B. Malinowsky
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under terms
of your choice, provided that you also meet, for each linked independent
module, the terms and conditions of the license of that module. An
independent module is a module which is not derived from or based on
this library. If you modify this library, you may extend this exception
to your version of the library, but you are not obligated to do so. If
you do not wish to do so, delete this exception statement from your
version.
*/
package tuwien.auto.calimero.link;
import java.time.Duration;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Consumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import tuwien.auto.calimero.CloseEvent;
import tuwien.auto.calimero.KNXAddress;
import tuwien.auto.calimero.KNXException;
import tuwien.auto.calimero.KNXIllegalArgumentException;
import tuwien.auto.calimero.KNXRemoteException;
import tuwien.auto.calimero.KNXTimeoutException;
import tuwien.auto.calimero.Priority;
import tuwien.auto.calimero.cemi.CEMILData;
import tuwien.auto.calimero.internal.Executor;
import tuwien.auto.calimero.link.medium.KNXMediumSettings;
/**
* Connector for KNX network links.
*
* @author B. Malinowsky
*/
public final class Connector
{
// TODO with functional interfaces, we should move away from checked exceptions
@FunctionalInterface
public interface TSupplier
{
T get() throws KNXException, InterruptedException;
}
private boolean onSend = true;
private long reconnectDelay = 4000; // [ms]
// reconnect on disconnect caused by:
private boolean initialError;
private boolean serverError = true;
private boolean internalError = true;
// runs out earliest after (2^63-1)/1000/3600/24/365 ~ 3×10^8 years. Safe bet KNX got canned by then
public static final long NoMaxAttempts = Long.MAX_VALUE;
private long maxAttempts = NoMaxAttempts;
private volatile Consumer connectionStatusChanged = __ -> {};
public Connector() {}
// copy ctor
private Connector(final Connector rhs)
{
this.onSend = rhs.onSend;
this.reconnectDelay = rhs.reconnectDelay;
this.initialError = rhs.initialError;
this.serverError = rhs.serverError;
this.internalError = rhs.internalError;
this.maxAttempts = rhs.maxAttempts;
this.connectionStatusChanged = rhs.connectionStatusChanged;
}
// on successful connection, the attempts are reset to maxAttempts
public Connector maxConnectAttempts(final long maxAttempts)
{
if (maxAttempts < 0)
throw new KNXIllegalArgumentException("max. connect attempts " + maxAttempts + " < 0");
this.maxAttempts = maxAttempts;
return this;
}
public Connector connectOnSend(final boolean connect)
{
onSend = connect;
return this;
}
public Connector reconnectDelay(final Duration delay) {
reconnectDelay = delay.toMillis();
return this;
}
public Connector reconnectOn(final boolean errorOnCreation, final boolean serverDisconnect,
final boolean internalDisconnect)
{
initialError = errorOnCreation;
serverError = serverDisconnect;
internalError = internalDisconnect;
return this;
}
public Connector connectionStatusNotifier(final Consumer connected) {
connectionStatusChanged = connected;
return this;
}
/**
* Returns a new KNXNetworkLink with the specified behavior for (re-)connection to the KNX network.
*
* @param creator supplies the specific KNX network link
* @return a new KNX network link with the specified (re-)connection behavior configured
* @throws KNXException on error creating the network link
* @throws InterruptedException on interrupted thread
*/
public KNXNetworkLink newLink(final TSupplier creator)
throws KNXException, InterruptedException
{
return new Link(creator, this);
}
/**
* Returns a new KNXNetworkMonitor with the specified behavior for (re-)connection to the KNX network.
*
* @param creator supplies the specific KNX network monitor
* @return a new KNX network monitor with the specified (re-)connection behavior configured
* @throws KNXException on error creating the monitor link
* @throws InterruptedException on interrupted thread
*/
public KNXNetworkMonitor newMonitor(final TSupplier creator)
throws KNXException, InterruptedException
{
return new Link(creator, this);
}
// interruption policy: close link resource
public static final class Link
implements KNXNetworkLink, KNXNetworkMonitor, NetworkLinkListener
{
private volatile T impl;
private final List listeners = new CopyOnWriteArrayList<>();
private volatile KNXMediumSettings settings;
private volatile int hopCount;
// monitor: decode raw frames
private volatile boolean decodeRawFrames;
private final TSupplier creator;
// we save a copy of the connector options that won't get modified
private final Connector connector;
private volatile boolean closed;
private volatile Future f = CompletableFuture.completedFuture(Void.TYPE);
private final AtomicBoolean connecting = new AtomicBoolean();
private final Object lock = new Object();
private Link(final TSupplier creator, final Connector options)
throws KNXException, InterruptedException
{
this.creator = creator;
connector = new Connector(options);
try {
connect();
}
catch (final KNXException e) {
if (!connector.initialError || connector.maxAttempts <= 1)
throw e;
logger().error("initial connection attempt", e);
scheduleConnect(connector.maxAttempts - 1);
}
}
/**
* @return the currently used connection instance of type {@link KNXNetworkLink} or
* {@link KNXNetworkMonitor}, or null
*/
public AutoCloseable target()
{
return impl;
}
@Override
public void setKNXMedium(final KNXMediumSettings settings)
{
final T t = impl;
if (t instanceof final KNXNetworkLink link)
link.setKNXMedium(settings);
else if (t instanceof final KNXNetworkMonitor monitor)
monitor.setKNXMedium(settings);
this.settings = settings;
}
@Override
public KNXMediumSettings getKNXMedium()
{
final T t = impl;
if (t instanceof final KNXNetworkLink link)
return link.getKNXMedium();
if (t instanceof final KNXNetworkMonitor monitor)
return monitor.getKNXMedium();
return settings;
}
@Override
public void addLinkListener(final NetworkLinkListener l)
{
if (impl instanceof final KNXNetworkLink link)
link.addLinkListener(l);
listeners.add(l);
}
@Override
public void removeLinkListener(final NetworkLinkListener l)
{
listeners.remove(l);
if (impl instanceof final KNXNetworkLink link)
link.removeLinkListener(l);
}
@Override
public void addMonitorListener(final LinkListener l)
{
if (impl instanceof final KNXNetworkMonitor monitor)
monitor.addMonitorListener(l);
listeners.add(l);
}
@Override
public void removeMonitorListener(final LinkListener l)
{
listeners.remove(l);
if (impl instanceof final KNXNetworkMonitor monitor)
monitor.removeMonitorListener(l);
}
@Override
public void setDecodeRawFrames(final boolean decode)
{
decodeRawFrames = decode;
if (impl instanceof final KNXNetworkMonitor monitor)
monitor.setDecodeRawFrames(decode);
}
@Override
public void setHopCount(final int count)
{
if (impl instanceof final KNXNetworkLink link)
link.setHopCount(count);
hopCount = count;
}
@Override
public int getHopCount()
{
return impl != null ? ((KNXNetworkLink) impl).getHopCount() : hopCount;
}
@Override
public void sendRequest(final KNXAddress dst, final Priority p, final byte[] nsdu)
throws KNXTimeoutException, KNXLinkClosedException
{
link().sendRequest(dst, p, nsdu);
}
@Override
public void sendRequestWait(final KNXAddress dst, final Priority p, final byte[] nsdu)
throws KNXTimeoutException, KNXLinkClosedException
{
link().sendRequestWait(dst, p, nsdu);
}
@Override
public void send(final CEMILData msg, final boolean waitForCon) throws KNXTimeoutException,
KNXLinkClosedException
{
link().send(msg, waitForCon);
}
@Override
public String getName()
{
final T t = impl;
if (t instanceof final KNXNetworkLink link)
return link.getName();
if (t instanceof final KNXNetworkMonitor monitor)
return monitor.getName();
return "connector";
}
@Override
public boolean isOpen()
{
return !closed;
}
@Override
public void close()
{
closed = true;
f.cancel(true);
try {
if (impl != null)
impl.close();
}
catch (final Exception ignore) {}
}
@Override
public void linkClosed(final CloseEvent e)
{
connector.connectionStatusChanged.accept(false);
if ((e.getInitiator() == CloseEvent.INTERNAL && connector.internalError)
|| (e.getInitiator() == CloseEvent.SERVER_REQUEST && connector.serverError))
scheduleConnect(connector.maxAttempts);
}
@Override
public String toString() {
final var v = impl;
return v != null ? v.toString() : "link connecting...";
}
// only called for network link send
private KNXNetworkLink link() throws KNXLinkClosedException
{
try {
final KNXNetworkLink l = (KNXNetworkLink) impl;
// ??? should immediate connects here also count for scheduled connects, and
// increment the attempt counter?
return (KNXNetworkLink) (l == null ? connect()
: l.isOpen() ? l : connector.onSend ? connect() : l);
}
catch (final InterruptedException e) {
Thread.currentThread().interrupt();
throw new KNXLinkClosedException("interrupt on reconnecting link", e);
}
catch (final KNXLinkClosedException e) {
throw e;
}
catch (final KNXException e) {
throw new KNXLinkClosedException("reconnecting link", e);
}
}
private void scheduleConnect(final long remainingAttempts)
{
if (closed)
return;
if (remainingAttempts <= 0) {
closed = true;
final var closed = new CloseEvent(this, CloseEvent.INTERNAL,
"reached max. connect attempts of " + connector.maxAttempts);
listeners.forEach(l -> l.linkClosed(closed));
return;
}
final long max = connector.maxAttempts;
final long remaining = remainingAttempts - 1;
final long attempt = max - remaining;
final Runnable s = () -> {
Thread.currentThread().setName("Calimero Connector");
try {
final String maxSuffix;
if (connector.maxAttempts == NoMaxAttempts)
maxSuffix = " (no max)";
else
maxSuffix = "/" + max + " (" + remaining + " remaining)";
logger().debug("execute scheduled connect {}{}", attempt, maxSuffix);
connect();
}
catch (KNXException | RuntimeException | InterruptedException e) {
if (attempt == 1)
logger().warn("connection attempt {}", attempt, e);
else {
final Throwable cause = e.getCause();
final String detail = cause != null && cause.getMessage() != null ? " (" + cause.getMessage() + ")" : "";
logger().warn("connection attempt {}: {}{}", attempt, e.getMessage(), detail);
}
scheduleConnect(remaining);
}
};
f = Executor.scheduledExecutor().schedule(s, connector.reconnectDelay, TimeUnit.MILLISECONDS);
}
private AutoCloseable connect() throws InterruptedException, KNXException
{
if (targetOpen()) {
return impl;
}
// if currently no connection attempt is active, we create one
if (connecting.compareAndSet(false, true)) {
try {
final T t = creator.get();
if (t instanceof final KNXNetworkLink link) {
if (impl == null) {
settings = link.getKNXMedium();
hopCount = link.getHopCount();
}
link.setKNXMedium(settings);
link.setHopCount(hopCount);
link.addLinkListener(this);
if (link instanceof final AbstractLink abstractLink)
abstractLink.wrappedByConnector = true;
listeners.forEach(l -> link.addLinkListener((NetworkLinkListener) l));
}
else if (t instanceof final KNXNetworkMonitor monitor) {
monitor.setDecodeRawFrames(decodeRawFrames);
monitor.addMonitorListener(this);
if (monitor instanceof final AbstractMonitor abstractLink)
abstractLink.wrappedByConnector = true;
listeners.forEach(monitor::addMonitorListener);
}
impl = t;
}
catch (final KNXRemoteException e) {
throw new KNXLinkClosedException(e.getMessage(), e);
}
finally {
connecting.set(false);
synchronized (lock) {
lock.notifyAll();
}
}
connector.connectionStatusChanged.accept(true);
}
else {
// if a connection attempt is active, we use that one
synchronized (lock) {
while (connecting.get())
lock.wait();
}
if (!targetOpen())
throw new KNXLinkClosedException("ongoing connect attempt we waited for failed");
}
return impl;
}
private boolean targetOpen()
{
final T t = impl;
if (t instanceof final KNXNetworkLink link)
return link.isOpen();
if (t instanceof final KNXNetworkMonitor monitor)
return monitor.isOpen();
return false;
}
private Logger logger()
{
return LoggerFactory.getLogger("calimero.link." + getName());
}
}
}