1 /* 2 * Copyright (c) 1997, 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 com.sun.xml.internal.org.jvnet.mimepull; 27 28 import java.io.BufferedReader; 29 import java.io.IOException; 30 import java.io.InputStream; 31 import java.io.InputStreamReader; 32 import java.nio.charset.StandardCharsets; 33 import java.util.logging.Level; 34 import java.util.logging.Logger; 35 36 class FactoryFinder { 37 38 private static ClassLoader cl = FactoryFinder.class.getClassLoader(); 39 40 static Object find(String factoryId) throws ClassNotFoundException, 41 InstantiationException, IllegalAccessException { 42 String systemProp = System.getProperty(factoryId); 43 if (systemProp != null) { 44 return newInstance(systemProp); 45 } 46 47 String providerName = findJarServiceProviderName(factoryId); 48 if (providerName != null && providerName.trim().length() > 0) { 49 return newInstance(providerName); 50 } 51 52 return null; 53 } 54 55 static Object newInstance(String className) throws ClassNotFoundException, 56 InstantiationException, IllegalAccessException { 57 Class providerClass = cl.loadClass(className); 58 Object instance = providerClass.newInstance(); 59 return instance; 60 } 61 62 private static String findJarServiceProviderName(String factoryId) { 63 String serviceId = "META-INF/services/" + factoryId; 64 InputStream is; 65 is = cl.getResourceAsStream(serviceId); 66 67 if (is == null) { 68 return null; 69 } 70 71 String factoryClassName; 72 BufferedReader rd = null; 73 try { 74 rd = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8)); 75 try { 76 factoryClassName = rd.readLine(); 77 } catch (IOException x) { 78 return null; 79 } 80 } finally { 81 if (rd != null) { 82 try { 83 rd.close(); 84 } catch (IOException ex) { 85 Logger.getLogger(FactoryFinder.class.getName()).log(Level.INFO, null, ex); 86 } 87 } 88 } 89 90 return factoryClassName; 91 } 92 93 }