| /** |
| * 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.io; |
| |
| import java.io.*; |
| import java.net.Socket; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.FileChannel; |
| import java.nio.channels.WritableByteChannel; |
| |
| import org.apache.commons.logging.Log; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| |
| /** |
| * An utility class for I/O related functionality. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Evolving |
| public class IOUtils { |
| |
| /** |
| * Copies from one stream to another. |
| * |
| * @param in InputStrem to read from |
| * @param out OutputStream to write to |
| * @param buffSize the size of the buffer |
| * @param close whether or not close the InputStream and |
| * OutputStream at the end. The streams are closed in the finally clause. |
| */ |
| public static void copyBytes(InputStream in, OutputStream out, int buffSize, boolean close) |
| throws IOException { |
| try { |
| copyBytes(in, out, buffSize); |
| if(close) { |
| out.close(); |
| out = null; |
| in.close(); |
| in = null; |
| } |
| } finally { |
| if(close) { |
| closeStream(out); |
| closeStream(in); |
| } |
| } |
| } |
| |
| /** |
| * Copies from one stream to another. |
| * |
| * @param in InputStrem to read from |
| * @param out OutputStream to write to |
| * @param buffSize the size of the buffer |
| */ |
| public static void copyBytes(InputStream in, OutputStream out, int buffSize) |
| throws IOException { |
| PrintStream ps = out instanceof PrintStream ? (PrintStream)out : null; |
| byte buf[] = new byte[buffSize]; |
| int bytesRead = in.read(buf); |
| while (bytesRead >= 0) { |
| out.write(buf, 0, bytesRead); |
| if ((ps != null) && ps.checkError()) { |
| throw new IOException("Unable to write to output stream."); |
| } |
| bytesRead = in.read(buf); |
| } |
| } |
| |
| /** |
| * Copies from one stream to another. <strong>closes the input and output streams |
| * at the end</strong>. |
| * |
| * @param in InputStrem to read from |
| * @param out OutputStream to write to |
| * @param conf the Configuration object |
| */ |
| public static void copyBytes(InputStream in, OutputStream out, Configuration conf) |
| throws IOException { |
| copyBytes(in, out, conf.getInt("io.file.buffer.size", 4096), true); |
| } |
| |
| /** |
| * Copies from one stream to another. |
| * |
| * @param in InputStream to read from |
| * @param out OutputStream to write to |
| * @param conf the Configuration object |
| * @param close whether or not close the InputStream and |
| * OutputStream at the end. The streams are closed in the finally clause. |
| */ |
| public static void copyBytes(InputStream in, OutputStream out, Configuration conf, boolean close) |
| throws IOException { |
| copyBytes(in, out, conf.getInt("io.file.buffer.size", 4096), close); |
| } |
| |
| /** |
| * Copies count bytes from one stream to another. |
| * |
| * @param in InputStream to read from |
| * @param out OutputStream to write to |
| * @param count number of bytes to copy |
| * @param close whether to close the streams |
| * @throws IOException if bytes can not be read or written |
| */ |
| public static void copyBytes(InputStream in, OutputStream out, long count, |
| boolean close) throws IOException { |
| byte buf[] = new byte[4096]; |
| long bytesRemaining = count; |
| int bytesRead; |
| |
| try { |
| while (bytesRemaining > 0) { |
| int bytesToRead = (int) |
| (bytesRemaining < buf.length ? bytesRemaining : buf.length); |
| |
| bytesRead = in.read(buf, 0, bytesToRead); |
| if (bytesRead == -1) |
| break; |
| |
| out.write(buf, 0, bytesRead); |
| bytesRemaining -= bytesRead; |
| } |
| if (close) { |
| out.close(); |
| out = null; |
| in.close(); |
| in = null; |
| } |
| } finally { |
| if (close) { |
| closeStream(out); |
| closeStream(in); |
| } |
| } |
| } |
| |
| /** |
| * Utility wrapper for reading from {@link InputStream}. It catches any errors |
| * thrown by the underlying stream (either IO or decompression-related), and |
| * re-throws as an IOException. |
| * |
| * @param is - InputStream to be read from |
| * @param buf - buffer the data is read into |
| * @param off - offset within buf |
| * @param len - amount of data to be read |
| * @return number of bytes read |
| */ |
| public static int wrappedReadForCompressedData(InputStream is, byte[] buf, |
| int off, int len) throws IOException { |
| try { |
| return is.read(buf, off, len); |
| } catch (IOException ie) { |
| throw ie; |
| } catch (Throwable t) { |
| throw new IOException("Error while reading compressed data", t); |
| } |
| } |
| |
| /** |
| * Reads len bytes in a loop. |
| * |
| * @param in InputStream to read from |
| * @param buf The buffer to fill |
| * @param off offset from the buffer |
| * @param len the length of bytes to read |
| * @throws IOException if it could not read requested number of bytes |
| * for any reason (including EOF) |
| */ |
| public static void readFully(InputStream in, byte buf[], |
| int off, int len) throws IOException { |
| int toRead = len; |
| while (toRead > 0) { |
| int ret = in.read(buf, off, toRead); |
| if (ret < 0) { |
| throw new IOException( "Premature EOF from inputStream"); |
| } |
| toRead -= ret; |
| off += ret; |
| } |
| } |
| |
| /** |
| * Similar to readFully(). Skips bytes in a loop. |
| * @param in The InputStream to skip bytes from |
| * @param len number of bytes to skip. |
| * @throws IOException if it could not skip requested number of bytes |
| * for any reason (including EOF) |
| */ |
| public static void skipFully(InputStream in, long len) throws IOException { |
| long amt = len; |
| while (amt > 0) { |
| long ret = in.skip(amt); |
| if (ret == 0) { |
| // skip may return 0 even if we're not at EOF. Luckily, we can |
| // use the read() method to figure out if we're at the end. |
| int b = in.read(); |
| if (b == -1) { |
| throw new EOFException( "Premature EOF from inputStream after " + |
| "skipping " + (len - amt) + " byte(s)."); |
| } |
| ret = 1; |
| } |
| amt -= ret; |
| } |
| } |
| |
| /** |
| * Close the Closeable objects and <b>ignore</b> any {@link IOException} or |
| * null pointers. Must only be used for cleanup in exception handlers. |
| * |
| * @param log the log to record problems to at debug level. Can be null. |
| * @param closeables the objects to close |
| */ |
| public static void cleanup(Log log, java.io.Closeable... closeables) { |
| for (java.io.Closeable c : closeables) { |
| if (c != null) { |
| try { |
| c.close(); |
| } catch(IOException e) { |
| if (log != null && log.isDebugEnabled()) { |
| log.debug("Exception in closing " + c, e); |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Closes the stream ignoring {@link IOException}. |
| * Must only be called in cleaning up from exception handlers. |
| * |
| * @param stream the Stream to close |
| */ |
| public static void closeStream(java.io.Closeable stream) { |
| cleanup(null, stream); |
| } |
| |
| /** |
| * Closes the socket ignoring {@link IOException} |
| * |
| * @param sock the Socket to close |
| */ |
| public static void closeSocket(Socket sock) { |
| if (sock != null) { |
| try { |
| sock.close(); |
| } catch (IOException ignored) { |
| } |
| } |
| } |
| |
| /** |
| * The /dev/null of OutputStreams. |
| */ |
| public static class NullOutputStream extends OutputStream { |
| @Override |
| public void write(byte[] b, int off, int len) throws IOException { |
| } |
| |
| @Override |
| public void write(int b) throws IOException { |
| } |
| } |
| |
| /** |
| * Write a ByteBuffer to a WritableByteChannel, handling short writes. |
| * |
| * @param bc The WritableByteChannel to write to |
| * @param buf The input buffer |
| * @throws IOException On I/O error |
| */ |
| public static void writeFully(WritableByteChannel bc, ByteBuffer buf) |
| throws IOException { |
| do { |
| bc.write(buf); |
| } while (buf.remaining() > 0); |
| } |
| |
| /** |
| * Write a ByteBuffer to a FileChannel at a given offset, |
| * handling short writes. |
| * |
| * @param fc The FileChannel to write to |
| * @param buf The input buffer |
| * @param offset The offset in the file to start writing at |
| * @throws IOException On I/O error |
| */ |
| public static void writeFully(FileChannel fc, ByteBuffer buf, |
| long offset) throws IOException { |
| do { |
| offset += fc.write(buf, offset); |
| } while (buf.remaining() > 0); |
| } |
| } |