| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.fs; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * Implementers of this interface provide a read API that writes to a |
| * ByteBuffer, not a byte[]. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| public interface ByteBufferReadable { |
| /** |
| * Reads up to buf.remaining() bytes into buf. Callers should use |
| * buf.limit(..) to control the size of the desired read. |
| * <p/> |
| * After a successful call, buf.position() will be advanced by the number |
| * of bytes read and buf.limit() should be unchanged. |
| * <p/> |
| * In the case of an exception, the values of buf.position() and buf.limit() |
| * are undefined, and callers should be prepared to recover from this |
| * eventuality. |
| * <p/> |
| * Many implementations will throw {@link UnsupportedOperationException}, so |
| * callers that are not confident in support for this method from the |
| * underlying filesystem should be prepared to handle that exception. |
| * <p/> |
| * Implementations should treat 0-length requests as legitimate, and must not |
| * signal an error upon their receipt. |
| * |
| * @param buf |
| * the ByteBuffer to receive the results of the read operation. |
| * @return the number of bytes read, possibly zero, or -1 if |
| * reach end-of-stream |
| * @throws IOException |
| * if there is some error performing the read |
| */ |
| public int read(ByteBuffer buf) throws IOException; |
| } |