1 /* 2 * Copyright (c) 2009, 2010, 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 package com.sun.beans.finder; 26 27 /** 28 * This is utility class that provides basic functionality 29 * to find an auxiliary class for a JavaBean specified by its type. 30 * 31 * @since 1.7 32 * 33 * @author Sergey A. Malenkov 34 */ 35 class InstanceFinder<T> { 36 37 private static final String[] EMPTY = { }; 38 39 private final Class<? extends T> type; 40 private final boolean allow; 41 private final String suffix; 42 private volatile String[] packages; 43 44 InstanceFinder(Class<? extends T> type, boolean allow, String suffix, String... packages) { 45 this.type = type; 46 this.allow = allow; 47 this.suffix = suffix; 48 this.packages = packages.clone(); 49 } 50 51 public String[] getPackages() { 52 return this.packages.clone(); 53 } 54 55 public void setPackages(String... packages) { 56 this.packages = (packages != null) && (packages.length > 0) 57 ? packages.clone() 58 : EMPTY; 59 } 60 61 public T find(Class<?> type) { 62 if (type == null) { 63 return null; 64 } 65 String name = type.getName() + this.suffix; 66 T object = instantiate(type, name); 67 if (object != null) { 68 return object; 69 } 70 if (this.allow) { 71 object = instantiate(type, null); 72 if (object != null) { 73 return object; 74 } 75 } 76 int index = name.lastIndexOf('.') + 1; 77 if (index > 0) { 78 name = name.substring(index); 79 } 80 for (String prefix : this.packages) { 81 object = instantiate(type, prefix, name); 82 if (object != null) { 83 return object; 84 } 85 } 86 return null; 87 } 88 89 protected T instantiate(Class<?> type, String name) { 90 if (type != null) { 91 try { 92 if (name != null) { 93 type = ClassFinder.findClass(name, type.getClassLoader()); 94 } 95 if (this.type.isAssignableFrom(type)) { 96 return (T) type.newInstance(); 97 } 98 } 99 catch (Exception exception) { 100 // ignore any exceptions 101 } 102 } 103 return null; 104 } 105 106 protected T instantiate(Class<?> type, String prefix, String name) { 107 return instantiate(type, prefix + '.' + name); 108 } 109 }