org.xbib.helianthus.common.http.HttpMessageAggregator Maven / Gradle / Ivy

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package org.xbib.helianthus.common.http;

import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;

abstract class HttpMessageAggregator implements Subscriber {

    private final List contentList = new ArrayList<>();

    private final CompletableFuture future;

    private int contentLength;

    private Subscription subscription;

    protected HttpMessageAggregator(CompletableFuture future) {
        this.future = future;
    }

    protected final CompletableFuture future() {
        return future;
    }

    @Override
    public void onSubscribe(Subscription s) {
        subscription = s;
        s.request(Long.MAX_VALUE);
    }

    protected final void add(HttpData data) {
        final int dataLength = data.length();
        if (dataLength > 0) {
            if (contentLength > Integer.MAX_VALUE - dataLength) {
                clear();
                subscription.cancel();
                throw new IllegalStateException("content length greater than Integer.MAX_VALUE");
            }
            contentList.add(data);
            contentLength += dataLength;
        }
    }

    protected final void clear() {
        doClear();
        contentList.clear();
    }

    protected void doClear() {
    }

    protected final HttpData finish() {
        final HttpData content;
        if (contentLength == 0) {
            content = HttpData.EMPTY_DATA;
        } else {
            final byte[] merged = new byte[contentLength];
            for (int i = 0, offset = 0; i < contentList.size(); i++) {
                final HttpData data = contentList.set(i, null);
                final int dataLength = data.length();
                System.arraycopy(data.array(), data.offset(), merged, offset, dataLength);
                offset += dataLength;
            }
            content = HttpData.of(merged);
        }
        return content;
    }
}