/*
* Copyright (c) 2005, 2006, 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.net.URL;
import java.net.URLClassLoader;
import java.net.MalformedURLException;
import java.util.Locale;
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 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> 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;
}
/**
* 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() {
if (Lazy.compilerClass == null)
return trace(WARNING, "Lazy.compilerClass == null");
try {
return Lazy.compilerClass.newInstance();
} catch (Throwable e) {
return trace(WARNING, e);
}
}
/**
* 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() {
if (Lazy.compilerClass == null)
return trace(WARNING, "Lazy.compilerClass == null");
return Lazy.compilerClass.getClassLoader();
}
/**
* This class will not be initialized until one of the above
* methods are called. This ensures that searching for the
* compiler does not affect platform start up.
*/
static class Lazy {
private static final String defaultJavaCompilerName
= "com.sun.tools.javac.api.JavacTool";
private static final String[] defaultToolsLocation
= { "lib", "tools.jar" };
static final Class<? extends JavaCompiler> compilerClass;
static {
Class<? extends JavaCompiler> c = null;
try {
c = findClass().asSubclass(JavaCompiler.class);
} catch (Throwable t) {
trace(WARNING, t);
}
compilerClass = c;
}
private static Class<?> findClass()
throws MalformedURLException, ClassNotFoundException
{
try {
return enableAsserts(Class.forName(defaultJavaCompilerName, false, null));
} catch (ClassNotFoundException e) {
trace(FINE, e);
}
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);
URL[] urls = {file.toURI().toURL()};
trace(FINE, urls[0].toString());
ClassLoader cl = URLClassLoader.newInstance(urls);
cl.setPackageAssertionStatus("com.sun.tools.javac", true);
return Class.forName(defaultJavaCompilerName, false, cl);
}
private static Class<?> enableAsserts(Class<?> cls) {
try {
ClassLoader loader = cls.getClassLoader();
if (loader != null)
loader.setPackageAssertionStatus("com.sun.tools.javac", true);
else
trace(FINE, "loader == null");
} catch (SecurityException ex) {
trace(FINE, ex);
}
return cls;
}
}
}