/*

* Copyright 2014 The gRPC 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 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 {@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;

}