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. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.internal.jimage; 27 28 import java.io.IOException; 29 import java.io.UncheckedIOException; 30 import java.nio.file.Path; 31 import java.nio.file.Paths; 32 import java.util.concurrent.ConcurrentHashMap; 33 import java.util.Map; 34 35 /** 36 * Factory to get ImageReader 37 */ 38 public class ImageReaderFactory { 39 private ImageReaderFactory() {} 40 41 private static final String JAVA_HOME = System.getProperty("java.home"); 42 private static final Path BOOT_MODULES_JIMAGE = 43 Paths.get(JAVA_HOME, "lib", "modules", "bootmodules.jimage"); 44 45 private static final Map<Path, ImageReader> readers = new ConcurrentHashMap<>(); 46 47 /** 48 * Returns an {@code ImageReader} to read from the given image file 49 */ 50 public static ImageReader get(Path jimage) throws IOException { 51 ImageReader reader = readers.get(jimage); 52 if (reader != null) { 53 return reader; 54 } 55 reader = ImageReader.open(jimage.toString()); 56 // potential race with other threads opening the same URL 57 ImageReader r = readers.putIfAbsent(jimage, reader); 58 if (r == null) { 59 return reader; 60 } else { 61 reader.close(); 62 return r; 63 } 64 } 65 66 /** 67 * Returns the {@code ImageReader} to read the image file in this 68 * run-time image. 69 * 70 * @throws UncheckedIOException if an I/O error occurs 71 */ 72 public static ImageReader getImageReader() { 73 try { 74 return get(BOOT_MODULES_JIMAGE); 75 } catch (IOException ioe) { 76 throw new UncheckedIOException(ioe); 77 } 78 } 79 }