001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.discovery.jdk; 018 019 import java.util.Enumeration; 020 import java.io.IOException; 021 022 023 /** 024 * @author Richard A. Sitze 025 */ 026 public abstract class JDKHooks { 027 private static final JDKHooks jdkHooks; 028 029 static { 030 jdkHooks = new JDK12Hooks(); 031 } 032 033 protected JDKHooks() { } 034 035 /** 036 * Return singleton object representing JVM hooks/tools. 037 * 038 * TODO: add logic to detect JDK level. 039 */ 040 public static final JDKHooks getJDKHooks() { 041 return jdkHooks; 042 } 043 044 /** 045 * Get the system property 046 * 047 * @param propName name of the property 048 * @return value of the property 049 */ 050 public abstract String getSystemProperty(final String propName); 051 052 /** 053 * The thread context class loader is available for JDK 1.2 054 * or later, if certain security conditions are met. 055 * 056 * @return The thread context class loader, if available. 057 * Otherwise return null. 058 */ 059 public abstract ClassLoader getThreadContextClassLoader(); 060 061 /** 062 * The system class loader is available for JDK 1.2 063 * or later, if certain security conditions are met. 064 * 065 * @return The system class loader, if available. 066 * Otherwise return null. 067 */ 068 public abstract ClassLoader getSystemClassLoader(); 069 070 public abstract Enumeration getResources(ClassLoader loader, 071 String resourceName) 072 throws IOException; 073 }