Java tutorial
package com.devicehive.handler.command; /* * #%L * DeviceHive Backend Logic * %% * Copyright (C) 2016 DataArt * %% * Licensed 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. * #L% */ import com.devicehive.eventbus.EventBus; import com.devicehive.model.DeviceCommand; import com.devicehive.model.eventbus.Subscriber; import com.devicehive.model.eventbus.Subscription; import com.devicehive.model.rpc.Action; import com.devicehive.model.rpc.CommandSubscribeRequest; import com.devicehive.model.rpc.CommandSubscribeResponse; import com.devicehive.service.HazelcastService; import com.devicehive.shim.api.Request; import com.devicehive.shim.api.Response; import com.devicehive.shim.api.server.RequestHandler; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.util.Assert; import org.springframework.util.CollectionUtils; import java.util.*; public class CommandSubscribeRequestHandler implements RequestHandler { private static final int LIMIT = 100; @Autowired private EventBus eventBus; @Autowired private HazelcastService hazelcastService; @Override public Response handle(Request request) { CommandSubscribeRequest body = (CommandSubscribeRequest) request.getBody(); validate(body); Subscriber subscriber = new Subscriber(body.getSubscriptionId(), request.getReplyTo(), request.getCorrelationId()); Set<Subscription> subscriptions = new HashSet<>(); if (CollectionUtils.isEmpty(body.getNames())) { Subscription subscription = new Subscription(Action.COMMAND_EVENT.name(), body.getDevice()); subscriptions.add(subscription); } else { for (String name : body.getNames()) { Subscription subscription = new Subscription(Action.COMMAND_EVENT.name(), body.getDevice(), name); subscriptions.add(subscription); } } subscriptions.forEach(subscription -> eventBus.subscribe(subscriber, subscription)); Collection<DeviceCommand> commands = findCommands(body.getDevice(), body.getNames(), body.getTimestamp()); CommandSubscribeResponse subscribeResponse = new CommandSubscribeResponse(body.getSubscriptionId(), commands); return Response.newBuilder().withBody(subscribeResponse).withLast(false) .withCorrelationId(request.getCorrelationId()).buildSuccess(); } private void validate(CommandSubscribeRequest request) { Assert.notNull(request, "Request body is null"); Assert.notNull(request.getDevice(), "Device guid is null"); Assert.notNull(request.getSubscriptionId(), "Subscription id not provided"); } private Collection<DeviceCommand> findCommands(String device, Collection<String> names, Date timestamp) { return Optional.ofNullable(timestamp).map(t -> hazelcastService.find(null, names, Collections.singleton(device), LIMIT, t, null, null, DeviceCommand.class)) .orElse(Collections.emptyList()); } }