Drainable.java

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package io.grpc;

import java.io.IOException;
import java.io.OutputStream;

/**
 * Extension to an {@link java.io.InputStream} or alike by adding a method that transfers all
 * content to an {@link OutputStream}.
 *
 * <p>This can be used for optimizing for the case where the content of the input stream will be
 * written to an {@link OutputStream} eventually. Instead of copying the content to a byte array
 * through {@code read()}, then writing the the {@code OutputStream}, the implementation can write
 * the content directly to the {@code OutputStream}.
 */
public interface Drainable {

  /**
   * Transfers the entire contents of this stream to the specified target.
   *
   * @param target to write to.
   * @return number of bytes written.
   */
  int drainTo(OutputStream target) throws IOException;
}