InputStream that fills a buffer and runs a callback

Main.java

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;

import com.google.common.collect.AbstractIterator;
import com.google.common.collect.Iterators;
import org.apache.commons.io.IOUtils;

public class Main {

  public static void main(String[] args) throws Exception {
    BufferingInputStreamFactory.Callback callback = buffer -> System.out.println(new String(buffer, StandardCharsets.UTF_8));
    String string = "1234567890";
    InputStream src = new ByteArrayInputStream(string.getBytes(StandardCharsets.UTF_8));
    BufferingInputStreamFactory bis = new BufferingInputStreamFactory();
    InputStream bufferingStream = bis.getBufferingStream(src, 2, callback);
    IOUtils.read(bufferingStream, new byte[10]);
  }

  public static class BufferingInputStreamFactory {

    public InputStream getBufferingStream(final InputStream src, final int bufferSize, final Callback callback) {
      byte[] buffer = new byte[bufferSize];

      Iterator<InputStream> iterator = new AbstractIterator<InputStream>() {
        private boolean endOfStream = false;
        @Override
        protected InputStream computeNext() {
          if (endOfStream) {
            return endOfData();
          }
          try {
            int size = IOUtils.read(src, buffer, 0, bufferSize);
            if (size != bufferSize) {
              endOfStream = true;
            }
            callback.processBuffer(buffer);
            return new ByteArrayInputStream(buffer, 0, size);
          } catch (IOException e) {
            throw new RuntimeException(e);
          }
        }
      };

      return new SequenceInputStream(Iterators.asEnumeration(iterator));
    }

    @FunctionalInterface
    public interface Callback {
      void processBuffer(byte[] buffer);
    }
  }

}

out.log

12
34
56
78
90