/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package hivemall.mix.server;
import hivemall.mix.MixMessage;
import hivemall.mix.MixMessage.MixEventName;
import hivemall.mix.store.PartialArgminKLD;
import hivemall.mix.store.PartialAverage;
import hivemall.mix.store.PartialResult;
import hivemall.mix.store.SessionObject;
import hivemall.mix.store.SessionStore;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import java.util.concurrent.ConcurrentMap;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
@Sharable
public final class MixServerHandler extends SimpleChannelInboundHandler<MixMessage> {
@Nonnull
private final SessionStore sessionStore;
private final int syncThreshold;
private final float scale;
public MixServerHandler(@Nonnull SessionStore sessionStore, @Nonnegative int syncThreshold,
@Nonnegative float scale) {
super();
this.sessionStore = sessionStore;
this.syncThreshold = syncThreshold;
this.scale = scale;
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, MixMessage msg) throws Exception {
final MixEventName event = msg.getEvent();
switch (event) {
case average:
case argminKLD: {
SessionObject session = getSession(msg);
PartialResult partial = getPartialResult(msg, session);
mix(ctx, msg, partial, session);
break;
}
case closeGroup: {
closeGroup(msg);
break;
}
default:
throw new IllegalStateException("Unexpected event: " + event);
}
}
private void closeGroup(@Nonnull MixMessage msg) {
String groupId = msg.getGroupID();
if (groupId == null) {
return;
}
sessionStore.remove(groupId);
}
@Nonnull
private SessionObject getSession(@Nonnull MixMessage msg) {
String groupID = msg.getGroupID();
if (groupID == null) {
throw new IllegalStateException("JobID is not set in the request message");
}
SessionObject session = sessionStore.get(groupID);
session.incrRequest();
return session;
}
@Nonnull
private PartialResult getPartialResult(@Nonnull MixMessage msg, @Nonnull SessionObject session) {
final ConcurrentMap<Object, PartialResult> map = session.get();
Object feature = msg.getFeature();
PartialResult partial = map.get(feature);
if (partial == null) {
final MixEventName event = msg.getEvent();
switch (event) {
case average:
partial = new PartialAverage();
break;
case argminKLD:
partial = new PartialArgminKLD();
break;
default:
throw new IllegalStateException("Unexpected event: " + event);
}
PartialResult existing = map.putIfAbsent(feature, partial);
if (existing != null) {
partial = existing;
}
}
return partial;
}
private void mix(final ChannelHandlerContext ctx, final MixMessage requestMsg,
final PartialResult partial, final SessionObject session) {
final MixEventName event = requestMsg.getEvent();
final Object feature = requestMsg.getFeature();
final float weight = requestMsg.getWeight();
final float covar = requestMsg.getCovariance();
final short localClock = requestMsg.getClock();
final int deltaUpdates = requestMsg.getDeltaUpdates();
final boolean cancelRequest = requestMsg.isCancelRequest();
if (deltaUpdates <= 0) {
throw new IllegalArgumentException("Illegal deltaUpdates received: " + deltaUpdates);
}
MixMessage responseMsg = null;
try {
partial.lock();
if (cancelRequest) {
partial.subtract(weight, covar, deltaUpdates, scale);
} else {
int diffClock = partial.diffClock(localClock);
partial.add(weight, covar, deltaUpdates, scale);
if (diffClock >= syncThreshold) {// sync model if clock DIFF is above threshold
float averagedWeight = partial.getWeight(scale);
float meanCovar = partial.getCovariance(scale);
short globalClock = partial.getClock();
responseMsg = new MixMessage(event, feature, averagedWeight, meanCovar,
globalClock, 0 /* deltaUpdates */);
}
}
} finally {
partial.unlock();
}
if (responseMsg != null) {
session.incrResponse();
ctx.writeAndFlush(responseMsg);
}
}
}