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Library provides utility classes for Vertx project development.

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package co.easimart.vertx.stream;

import io.vertx.core.Handler;
import io.vertx.core.streams.ReadStream;

/**
 * ReadStream<T> which can be cancelled in the middle.
 * exceptionHandler will be called when it is cancelled.
 * If the stream has ended already, nothing happens.
 */
public class CancellableReadStream implements ReadStream {

    private Handler endHandler;
    private Handler exceptionHandler;
    private final ReadStream stream;
    private boolean ended;

    public CancellableReadStream(ReadStream stream) {
        this.stream = stream;

        this.ended = false;
        this.stream.exceptionHandler(throwable -> {
            if (this.exceptionHandler != null) this.exceptionHandler.handle(throwable);
        });
        this.stream.endHandler(r -> {
            this.ended = true;
            if (this.endHandler != null) this.endHandler.handle(r);
        });
    }

    @Override
    public ReadStream exceptionHandler(Handler handler) {
        this.exceptionHandler = handler;
        return this;
    }

    public void cancel(Throwable t) {
        if (this.ended) return;
        if (this.exceptionHandler != null) {
            this.exceptionHandler.handle(t);
        } else {
            this.stream.pause();
            this.endHandler.handle(null);
        }
    }

    @Override
    public ReadStream handler(Handler handler) {
        this.stream.handler(handler);
        return this;
    }

    @Override
    public ReadStream pause() {
        this.stream.pause();
        return this;
    }

    @Override
    public ReadStream resume() {
        this.stream.resume();
        return this;
    }

    @Override
    public ReadStream endHandler(Handler handler) {
        this.endHandler = handler;
        return this;
    }
}