1 /* 2 * Copyright (c) 2016, 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.util.jar; 27 28 import java.util.Objects; 29 import java.util.jar.JarEntry; 30 import java.util.jar.JarFile; 31 import java.util.stream.Stream; 32 33 public class VersionedStream { 34 private static final String META_INF_VERSIONS = "META-INF/versions/"; 35 36 /** 37 * Returns a stream of versioned entries, derived from the base names of 38 * all entries in a multi-release {@code JarFile} that are present either in 39 * the base directory or in any versioned directory with a version number 40 * less than or equal to the {@code Runtime.Version::major} that the 41 * {@code JarFile} was opened with. These versioned entries are aliases 42 * for the real entries -- i.e. the names are base names and the content 43 * may come from a versioned directory entry. If the {@code jarFile} is not 44 * a multi-release jar, a stream of all entries is returned. 45 * 46 * @param jf the input JarFile 47 * @return stream of entries 48 * @since 9 49 */ 50 public static Stream<JarEntry> stream(JarFile jf) { 51 if (jf.isMultiRelease()) { 52 int version = jf.getVersion().major(); 53 return jf.stream() 54 .map(je -> getBaseSuffix(je, version)) 55 .filter(Objects::nonNull) 56 .distinct() 57 .map(jf::getJarEntry); 58 } 59 return jf.stream(); 60 } 61 62 private static String getBaseSuffix(JarEntry je, int version) { 63 String name = je.getName(); 64 if (name.startsWith(META_INF_VERSIONS)) { 65 int len = META_INF_VERSIONS.length(); 66 int index = name.indexOf('/', len); 67 if (index == -1 || index == (name.length() - 1)) { 68 // filter out META-INF/versions/* and META-INF/versions/*/ 69 return null; 70 } 71 try { 72 if (Integer.parseInt(name, len, index, 10) > version) { 73 // not an integer 74 return null; 75 } 76 } catch (NumberFormatException x) { 77 // silently remove malformed entries 78 return null; 79 } 80 // We know name looks like META-INF/versions/*/* 81 return name.substring(index + 1); 82 } 83 return name; 84 } 85 }