io.atrato.pubsubserver.PubsubRestProvider.java Source code

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Here is the source code for io.atrato.pubsubserver.PubsubRestProvider.java

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/**
 * Copyright (c) 2017 Atrato, Inc. ALL Rights Reserved.
 *
 * 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.
 */
package io.atrato.pubsubserver;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.databind.JsonNode;
import org.apache.commons.lang3.BooleanUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.AsyncContext;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.NotFoundException;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import java.io.IOException;
import java.util.List;

/**
 * Created by david on 1/26/17.
 */
@Path("/pubsub")
public class PubsubRestProvider {
    private static final Logger LOG = LoggerFactory.getLogger(PubsubRestProvider.class);

    @JsonIgnoreProperties(ignoreUnknown = true)
    public static class NullInfo {
        public static final NullInfo INSTANCE = new NullInfo();

        private NullInfo() {
        }
    }

    @GET
    @Path("topics")
    @Produces(MediaType.APPLICATION_JSON)
    public List<PubsubBroker.TopicSummary> getTopics(@QueryParam("laterThan") Long timestamp,
            @Context HttpServletRequest request) {
        LOG.debug("getTopics");
        if (timestamp == null) {
            timestamp = -1L;
        }
        return PubsubServer.getBroker().getTopics(timestamp);
    }

    @GET
    @Path("topics/{topic}")
    @Produces(MediaType.APPLICATION_JSON)
    public PubsubBroker.TimedTopicData getTopicData(@PathParam("topic") String topic,
            @QueryParam("laterThan") Long timestamp, @QueryParam("poll") Boolean poll,
            @Context HttpServletRequest request) {
        if (timestamp == null) {
            timestamp = -1L;
        }
        //LOG.debug("topic: {} poll: {}", topic, poll);
        PubsubBroker.TimedTopicData data = PubsubServer.getBroker().getLatestTopicData(topic, timestamp);
        if (data == null) {
            if (BooleanUtils.isTrue(poll)) {
                AsyncContext asyncContext = request.startAsync();
                PubsubServer.getBroker().oneTimeSubscribe(asyncContext, topic);
                asyncContext.addListener(new AsyncListener() {
                    @Override
                    public void onComplete(AsyncEvent asyncEvent) throws IOException {
                        PubsubServer.getBroker().invalidateOneTimeSubscriber(asyncEvent.getAsyncContext());
                    }

                    @Override
                    public void onTimeout(AsyncEvent asyncEvent) throws IOException {
                        PubsubServer.getBroker().invalidateOneTimeSubscriber(asyncEvent.getAsyncContext());
                    }

                    @Override
                    public void onError(AsyncEvent asyncEvent) throws IOException {
                        PubsubServer.getBroker().invalidateOneTimeSubscriber(asyncEvent.getAsyncContext());
                    }

                    @Override
                    public void onStartAsync(AsyncEvent asyncEvent) throws IOException {
                    }
                });
                return null;
            } else {
                throw new NotFoundException();
            }
        }
        LOG.debug("topic: {} poll: {} data: {}", topic, poll, (data != null ? data.getData() : data));
        return data;
    }

    @POST
    @Path("topics/{topic}")
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.APPLICATION_JSON)
    public NullInfo postTopicData(@PathParam("topic") String topic, JsonNode data) {
        PubsubServer.getBroker().publish(topic, data);
        return NullInfo.INSTANCE;
    }
}