JerseyEventSink.java

/*
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 * and Distribution License("CDDL") (collectively, the "License").  You
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 * obtain a copy of the License at
 * http://glassfish.java.net/public/CDDL+GPL_1_1.html
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 * file and include the License file at packager/legal/LICENSE.txt.
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package org.glassfish.jersey.media.sse.internal;

import java.io.IOException;
import java.nio.charset.Charset;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.ws.rs.sse.OutboundSseEvent;
import javax.ws.rs.sse.SseEventSink;

import org.glassfish.jersey.internal.jsr166.Flow;
import org.glassfish.jersey.media.sse.LocalizationMessages;
import org.glassfish.jersey.server.ChunkedOutput;

/**
 * Server-side SSE subscriber.
 * <p>
 * The reference should be obtained via injection into the resource method.
 *
 * @author Adam Lindenthal (adam.lindenthal at oracle.com)]
 */
class JerseyEventSink extends ChunkedOutput<OutboundSseEvent> implements SseEventSink, Flow.Subscriber<OutboundSseEvent> {
    private static final Logger LOGGER = Logger.getLogger(JerseyEventSink.class.getName());
    private static final byte[] SSE_EVENT_DELIMITER = "\n".getBytes(Charset.forName("UTF-8"));
    private Flow.Subscription subscription = null;

    JerseyEventSink() {
        super(SSE_EVENT_DELIMITER);
    }

    @Override
    public void onSubscribe(final Flow.Subscription subscription) {
        checkClosed();
        if (subscription == null) {
            throw new NullPointerException(LocalizationMessages.PARAM_NULL("subscription"));
        }
        this.subscription = subscription;
        subscription.request(Long.MAX_VALUE);
    }


    @Override
    public void onNext(final OutboundSseEvent item) {
        checkClosed();
        if (item == null) {
            throw new NullPointerException(LocalizationMessages.PARAM_NULL("outboundSseEvent"));
        }
        try {
            write(item);
        } catch (final IOException e) {
            onError(e);
        }
    }

    @Override
    public void onError(final Throwable throwable) {
        checkClosed();
        if (throwable == null) {
            throw new NullPointerException(LocalizationMessages.PARAM_NULL("throwable"));
        }
        subscription.cancel();
    }

    @Override
    public void close() {
        try {
            super.close();
        } catch (IOException e) {
            LOGGER.log(Level.INFO, LocalizationMessages.EVENT_SINK_CLOSE_FAILED(), e);
        }
    }

    @Override
    public CompletionStage<?> send(OutboundSseEvent event) {
        try {
            this.write(event);
            return CompletableFuture.completedFuture(null);
        } catch (IOException e) {
            return CompletableFuture.completedFuture(e);
        }
    }

    public void onComplete() {
        checkClosed();
        subscription.cancel();
        close();
    }

    private void checkClosed() {
        if (isClosed()) {
            throw new IllegalStateException(LocalizationMessages.EVENT_SOURCE_ALREADY_CLOSED());
        }
    }
}