| /* |
| * 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.nemo.common; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| |
| /** |
| * This class is a customized input stream implementation which reads data from |
| * list of {@link ByteBuffer}. If the {@link ByteBuffer} is direct, it may reside outside |
| * the normal garbage-collected heap memory. |
| */ |
| public class ByteBufferInputStream extends InputStream { |
| private List<ByteBuffer> bufList; |
| private int current = 0; |
| private static final int BITMASK = 0xff; |
| |
| /** |
| * Default Constructor. |
| * |
| * @param bufList is the target data to read. |
| */ |
| public ByteBufferInputStream(final List<ByteBuffer> bufList) { |
| this.bufList = bufList; |
| } |
| |
| /** |
| * Reads data from the list of {@code ByteBuffer}s. |
| * |
| * @return integer. |
| * @throws IOException |
| */ |
| @Override |
| public int read() throws IOException { |
| // Since java's byte is signed type, we have to mask it to make byte |
| // become unsigned type to properly retrieve `int` from sequence of bytes. |
| return getBuffer().get() & BITMASK; |
| } |
| |
| /** |
| * Return next non-empty @code{ByteBuffer}. |
| * |
| * @return @code{ByteBuffer} to write the data |
| * @throws IOException when fail to retrieve buffer. |
| */ |
| public ByteBuffer getBuffer() throws IOException { |
| while (current < bufList.size()) { |
| ByteBuffer buffer = bufList.get(current); |
| if (buffer.hasRemaining()) { |
| return buffer; |
| } |
| current += 1; |
| } |
| throw new EOFException(); |
| } |
| } |