1 /* 2 * Copyright 2014 The gRPC Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.grpc; 18 19 import java.io.IOException; 20 import java.io.OutputStream; 21 22 /** 23 * Extension to an {@link java.io.InputStream} or alike by adding a method that transfers all 24 * content to an {@link OutputStream}. 25 * 26 * <p>This can be used for optimizing for the case where the content of the input stream will be 27 * written to an {@link OutputStream} eventually. Instead of copying the content to a byte array 28 * through {@code read()}, then writing the {@code OutputStream}, the implementation can write 29 * the content directly to the {@code OutputStream}. 30 */ 31 public interface Drainable { 32 33 /** 34 * Transfers the entire contents of this stream to the specified target. 35 * 36 * @param target to write to. 37 * @return number of bytes written. 38 */ drainTo(OutputStream target)39 int drainTo(OutputStream target) throws IOException; 40 } 41