1 /* 2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 4823133 27 * @summary optimize RandomAccessFile.length() and length() is thread safe now. 28 */ 29 import java.io.File; 30 import java.io.FileNotFoundException; 31 import java.io.FileOutputStream; 32 import java.io.IOException; 33 import java.io.RandomAccessFile; 34 35 /** 36 * 37 * @author vyom.tewari@oracle.com 38 */ 39 public class FileLengthTest { 40 41 private static final int BUF_SIZE = 4096; 42 private static RandomAccessFile randomAccessFile; 43 private static Thread fileLengthCaller; 44 private static Thread fileContentReader; 45 private static StringBuilder fileContents; 46 private static volatile boolean isFailed = false; 47 48 /** 49 * this thread will call length() in loop 50 */ 51 private static void startLengthThread() { 52 if (randomAccessFile == null) { 53 return; 54 } 55 fileLengthCaller = new Thread(() -> { 56 while (true) { 57 try { 58 long length = randomAccessFile.length(); 59 if (length < 0) { 60 return; 61 } 62 } catch (IOException ex) { 63 return; 64 } 65 } 66 }); 67 fileLengthCaller.setName("RandomAccessFile-length-caller"); 68 fileLengthCaller.setDaemon(true); 69 fileLengthCaller.start(); 70 } 71 72 /** 73 * this thread will call read() and store the content in internal buffer. 74 */ 75 private static void startReaderThread() { 76 if (randomAccessFile == null) { 77 return; 78 } 79 fileContentReader = new Thread(() -> { 80 StringBuilder sb = new StringBuilder(BUF_SIZE); 81 int i; 82 byte arr[] = new byte[8]; 83 try { 84 while ((i = randomAccessFile.read(arr)) != -1) { 85 sb.append(new String(arr, 0, i)); 86 } 87 if (!sb.toString().equals(fileContents.toString())) { 88 isFailed = true; 89 } 90 } catch (IOException ex) { 91 } 92 }); 93 fileContentReader.setName("RandomAccessFile-content-reader"); 94 fileContentReader.setDaemon(true); 95 fileContentReader.start(); 96 } 97 98 public static void main(String args[]) { 99 byte arr[] = new byte[BUF_SIZE]; 100 String testFile = "testfile.txt"; 101 try { 102 createDummyFile(testFile); 103 File file = new File(testFile); 104 file.deleteOnExit(); 105 randomAccessFile = new RandomAccessFile(file, "r"); 106 int count = randomAccessFile.read(arr); 107 randomAccessFile.seek(0); 108 fileContents = new StringBuilder(BUF_SIZE); 109 fileContents.append(new String(arr, 0, count)); 110 startLengthThread(); 111 startReaderThread(); 112 fileContentReader.join(); 113 } catch (FileNotFoundException | InterruptedException ex) { 114 } catch (IOException ex) { 115 } finally { 116 try { 117 randomAccessFile.close(); 118 } catch (IOException ex) { 119 } 120 } 121 if (isFailed) { 122 throw new RuntimeException("RandomAccessFile.length() changed the underlying file pointer."); 123 } 124 } 125 126 private static void createDummyFile(String fileName) throws FileNotFoundException, IOException { 127 try (FileOutputStream outputStream = new FileOutputStream(new File(fileName))) { 128 String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"; 129 int count = 0; 130 while ((count + str.length()) < BUF_SIZE) { 131 outputStream.write(str.getBytes()); 132 count += str.length(); 133 } 134 outputStream.flush(); 135 } 136 } 137 }