org.springframework.reactive.web.servlet.ResponseBodySubscriber.java Source code

Introduction

Here is the source code for org.springframework.reactive.web.servlet.ResponseBodySubscriber.java

Source

/*
 * Copyright 2002-2015 the original author or authors.
 *
 * 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 org.springframework.reactive.web.servlet;

import java.io.IOException;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;

import org.springframework.util.Assert;

/**
 * @author Arjen Poutsma
 */
public class ResponseBodySubscriber implements WriteListener, Subscriber<byte[]> {

    private static final Log logger = LogFactory.getLog(ResponseBodySubscriber.class);

    private final AsyncContextSynchronizer synchronizer;

    private Subscription subscription;

    private byte[] buffer;

    private volatile boolean subscriberComplete = false;

    public ResponseBodySubscriber(AsyncContextSynchronizer synchronizer) {
        this.synchronizer = synchronizer;
    }

    @Override
    public void onSubscribe(Subscription subscription) {
        this.subscription = subscription;
        this.subscription.request(1);
    }

    @Override
    public void onNext(byte[] bytes) {
        logger.debug("Next: " + bytes.length + " bytes");

        Assert.isNull(buffer);

        this.buffer = bytes;
        try {
            onWritePossible();
        } catch (IOException e) {
            onError(e);
        }
    }

    @Override
    public void onComplete() {
        logger.debug("Complete buffer: " + (buffer == null));

        this.subscriberComplete = true;

        if (buffer == null) {
            this.synchronizer.writeComplete();
        }
    }

    @Override
    public void onWritePossible() throws IOException {
        ServletOutputStream output = this.synchronizer.getOutputStream();

        boolean ready = output.isReady();
        logger.debug("Output: " + ready + " buffer: " + (buffer == null));

        if (ready) {
            if (this.buffer != null) {
                output.write(this.buffer);
                this.buffer = null;

                if (!subscriberComplete) {
                    this.subscription.request(1);
                } else {
                    this.synchronizer.writeComplete();
                }
            } else {
                this.subscription.request(1);
            }
        }
    }

    @Override
    public void onError(Throwable t) {
        logger.error("ResponseBodySubscriber error", t);
    }

}