/* * Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.tools; import java.io.File; import java.lang.ref.Reference; import java.lang.ref.WeakReference; import java.net.URL; import java.net.URLClassLoader; import java.net.MalformedURLException; import java.util.HashMap; import java.util.Locale; import java.util.Map; import java.util.logging.Logger; import java.util.logging.Level; import static java.util.logging.Level.*; /** * Provides methods for locating tool providers, for example, * providers of compilers. This class complements the * functionality of {@link java.util.ServiceLoader}. * * @author Peter von der Ahé * @since 1.6 */ public class ToolProvider { private static final String propertyName = "sun.tools.ToolProvider"; private static final String loggerName = "javax.tools"; /* * Define the system property "sun.tools.ToolProvider" to enable * debugging: * * java ... -Dsun.tools.ToolProvider ... */ static T trace(Level level, Object reason) { // NOTE: do not make this method private as it affects stack traces try { if (System.getProperty(propertyName) != null) { StackTraceElement[] st = Thread.currentThread().getStackTrace(); String method = "???"; String cls = ToolProvider.class.getName(); if (st.length > 2) { StackTraceElement frame = st[2]; method = String.format((Locale)null, "%s(%s:%s)", frame.getMethodName(), frame.getFileName(), frame.getLineNumber()); cls = frame.getClassName(); } Logger logger = Logger.getLogger(loggerName); if (reason instanceof Throwable) { logger.logp(level, cls, method, reason.getClass().getName(), (Throwable)reason); } else { logger.logp(level, cls, method, String.valueOf(reason)); } } } catch (SecurityException ex) { System.err.format((Locale)null, "%s: %s; %s%n", ToolProvider.class.getName(), reason, ex.getLocalizedMessage()); } return null; } private static final String defaultJavaCompilerName = "com.sun.tools.javac.api.JavacTool"; /** * Gets the Java™ programming language compiler provided * with this platform. * @return the compiler provided with this platform or * {@code null} if no compiler is provided */ public static JavaCompiler getSystemJavaCompiler() { return instance().getSystemTool(JavaCompiler.class, defaultJavaCompilerName); } private static final String defaultDocumentationToolName = "com.sun.tools.javadoc.api.JavadocTool"; /** * Gets the Java™ programming language documentation tool provided * with this platform. * @return the documentation tool provided with this platform or * {@code null} if no documentation tool is provided */ public static DocumentationTool getSystemDocumentationTool() { return instance().getSystemTool(DocumentationTool.class, defaultDocumentationToolName); } /** * Returns the class loader for tools provided with this platform. * This does not include user-installed tools. Use the * {@linkplain java.util.ServiceLoader service provider mechanism} * for locating user installed tools. * * @return the class loader for tools provided with this platform * or {@code null} if no tools are provided */ public static ClassLoader getSystemToolClassLoader() { try { Class c = instance().getSystemToolClass(JavaCompiler.class, defaultJavaCompilerName); return c.getClassLoader(); } catch (Throwable e) { return trace(WARNING, e); } } private static ToolProvider instance; private static synchronized ToolProvider instance() { if (instance == null) instance = new ToolProvider(); return instance; } // Cache for tool classes. // Use weak references to avoid keeping classes around unnecessarily private Map>> toolClasses = new HashMap>>(); // Cache for tool classloader. // Use a weak reference to avoid keeping it around unnecessarily private Reference refToolClassLoader = null; private ToolProvider() { } private T getSystemTool(Class clazz, String name) { Class c = getSystemToolClass(clazz, name); try { return c.asSubclass(clazz).newInstance(); } catch (Throwable e) { trace(WARNING, e); return null; } } private Class getSystemToolClass(Class clazz, String name) { Reference> refClass = toolClasses.get(name); Class c = (refClass == null ? null : refClass.get()); if (c == null) { try { c = findSystemToolClass(name); } catch (Throwable e) { return trace(WARNING, e); } toolClasses.put(name, new WeakReference>(c)); } return c.asSubclass(clazz); } private static final String[] defaultToolsLocation = { "lib", "tools.jar" }; private Class findSystemToolClass(String toolClassName) throws MalformedURLException, ClassNotFoundException { // try loading class directly, in case tool is on the bootclasspath try { return Class.forName(toolClassName, false, null); } catch (ClassNotFoundException e) { trace(FINE, e); // if tool not on bootclasspath, look in default tools location (tools.jar) ClassLoader cl = (refToolClassLoader == null ? null : refToolClassLoader.get()); if (cl == null) { File file = new File(System.getProperty("java.home")); if (file.getName().equalsIgnoreCase("jre")) file = file.getParentFile(); for (String name : defaultToolsLocation) file = new File(file, name); // if tools not found, no point in trying a URLClassLoader // so rethrow the original exception. if (!file.exists()) throw e; URL[] urls = { file.toURI().toURL() }; trace(FINE, urls[0].toString()); cl = URLClassLoader.newInstance(urls); refToolClassLoader = new WeakReference(cl); } return Class.forName(toolClassName, false, cl); } } }