+/*
+ * Copyright (c) 2020 PANTHEON.tech, s.r.o. and others. 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.opendaylight.mdsal.replicate.netty;
+
+import static java.util.Objects.requireNonNull;
+
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.timeout.IdleStateEvent;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class KeepaliveHandler extends ChannelDuplexHandler {
+ private static final Logger LOG = LoggerFactory.getLogger(KeepaliveHandler.class);
+
+ private final Runnable reconnect;
+
+ KeepaliveHandler(final Runnable reconnectCallback) {
+ this.reconnect = requireNonNull(reconnectCallback, "Reconnect callback should not be null");
+ }
+
+ @Override
+ public void userEventTriggered(final ChannelHandlerContext ctx, final Object evt) {
+ if (evt instanceof IdleStateEvent) {
+ ctx.writeAndFlush(Constants.PING);
+ } else {
+ ctx.fireUserEventTriggered(evt);
+ }
+ }
+
+ @Override
+ public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
+ LOG.warn("There was an exception on the channel. Attempting to reconnect.", cause);
+ reconnect.run();
+ }
+}