jdk-sandbox: comparison jaxp/src/share/classes/javax/xml/transform/FactoryFinder.java

equal deleted inserted replaced

-:16ba58282d11
+:a754d69d5e60
+/*
+* Copyright (c) 2003, 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.xml.transform;
+import java.io.File;
+import java.io.FileInputStream;
+import java.util.Properties;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+/**
+* <p>Implements pluggable Datatypes.</p>
+*
+* <p>This class is duplicated for each JAXP subpackage so keep it in
+* sync.  It is package private for secure class loading.</p>
+*
+* @author Santiago.PericasGeertsen@sun.com
+*/
+class FactoryFinder {
+/**
+* Internal debug flag.
+*/
+private static boolean debug = false;
+/**
+* Cache for properties in java.home/lib/jaxp.properties
+*/
+static Properties cacheProps = new Properties();
+/**
+* Flag indicating if properties from java.home/lib/jaxp.properties
+* have been cached.
+*/
+static boolean firstTime = true;
+/**
+* Security support class use to check access control before
+* getting certain system resources.
+*/
+static SecuritySupport ss = new SecuritySupport();
+// Define system property "jaxp.debug" to get output
+static {
+// Use try/catch block to support applets, which throws
+// SecurityException out of this code.
+try {
+String val = ss.getSystemProperty("jaxp.debug");
+// Allow simply setting the prop to turn on debug
+debug = val != null && !"false".equals(val);
+}
+catch (SecurityException se) {
+debug = false;
+}
+}
+private static void dPrint(String msg) {
+if (debug) {
+System.err.println("JAXP: " + msg);
+}
+}
+/**
+* Attempt to load a class using the class loader supplied. If that fails
+* and fall back is enabled, the current (i.e. bootstrap) class loader is
+* tried.
+*
+* If the class loader supplied is <code>null</code>, first try using the
+* context class loader followed by the current (i.e. bootstrap) class
+* loader.
+*/
+static private Class getProviderClass(String className, ClassLoader cl,
+boolean doFallback) throws ClassNotFoundException
+{
+try {
+if (cl == null) {
+cl = ss.getContextClassLoader();
+if (cl == null) {
+throw new ClassNotFoundException();
+}
+else {
+return cl.loadClass(className);
+}
+}
+else {
+return cl.loadClass(className);
+}
+}
+catch (ClassNotFoundException e1) {
+if (doFallback) {
+// Use current class loader - should always be bootstrap CL
+return Class.forName(className, true, FactoryFinder.class.getClassLoader());
+}
+else {
+throw e1;
+}
+}
+}
+/**
+* Create an instance of a class. Delegates to method
+* <code>getProviderClass()</code> in order to load the class.
+*
+* @param className Name of the concrete class corresponding to the
+* service provider
+*
+* @param cl ClassLoader to use to load the class, null means to use
+* the bootstrap ClassLoader
+*
+* @param doFallback True if the current ClassLoader should be tried as
+* a fallback if the class is not found using cl
+*/
+static Object newInstance(String className, ClassLoader cl, boolean doFallback)
+throws ConfigurationError
+{
+try {
+Class providerClass = getProviderClass(className, cl, doFallback);
+Object instance = providerClass.newInstance();
+if (debug) {    // Extra check to avoid computing cl strings
+dPrint("created new instance of " + providerClass +
+" using ClassLoader: " + cl);
+}
+return instance;
+}
+catch (ClassNotFoundException x) {
+throw new ConfigurationError(
+"Provider " + className + " not found", x);
+}
+catch (Exception x) {
+throw new ConfigurationError(
+"Provider " + className + " could not be instantiated: " + x,
+x);
+}
+}
+/**
+* Finds the implementation Class object in the specified order.  Main
+* entry point.
+* @return Class object of factory, never null
+*
+* @param factoryId             Name of the factory to find, same as
+*                              a property name
+* @param fallbackClassName     Implementation class name, if nothing else
+*                              is found.  Use null to mean no fallback.
+*
+* Package private so this code can be shared.
+*/
+static Object find(String factoryId, String fallbackClassName)
+throws ConfigurationError
+{
+dPrint("find factoryId =" + factoryId);
+// Use the system property first
+try {
+String systemProp = ss.getSystemProperty(factoryId);
+if (systemProp != null) {
+dPrint("found system property, value=" + systemProp);
+return newInstance(systemProp, null, true);
+}
+}
+catch (SecurityException se) {
+if (debug) se.printStackTrace();
+}
+// try to read from $java.home/lib/jaxp.properties
+try {
+String factoryClassName = null;
+if (firstTime) {
+synchronized (cacheProps) {
+if (firstTime) {
+String configFile = ss.getSystemProperty("java.home") + File.separator +
+"lib" + File.separator + "jaxp.properties";
+File f = new File(configFile);
+firstTime = false;
+if (ss.doesFileExist(f)) {
+dPrint("Read properties file "+f);
+cacheProps.load(ss.getFileInputStream(f));
+}
+}
+}
+}
+factoryClassName = cacheProps.getProperty(factoryId);
+if (factoryClassName != null) {
+dPrint("found in $java.home/jaxp.properties, value=" + factoryClassName);
+return newInstance(factoryClassName, null, true);
+}
+}
+catch (Exception ex) {
+if (debug) ex.printStackTrace();
+}
+// Try Jar Service Provider Mechanism
+Object provider = findJarServiceProvider(factoryId);
+if (provider != null) {
+return provider;
+}
+if (fallbackClassName == null) {
+throw new ConfigurationError(
+"Provider for " + factoryId + " cannot be found", null);
+}
+dPrint("loaded from fallback value: " + fallbackClassName);
+return newInstance(fallbackClassName, null, true);
+}
+/*
+* Try to find provider using Jar Service Provider Mechanism
+*
+* @return instance of provider class if found or null
+*/
+private static Object findJarServiceProvider(String factoryId)
+throws ConfigurationError
+{
+String serviceId = "META-INF/services/" + factoryId;
+InputStream is = null;
+// First try the Context ClassLoader
+ClassLoader cl = ss.getContextClassLoader();
+if (cl != null) {
+is = ss.getResourceAsStream(cl, serviceId);
+// If no provider found then try the current ClassLoader
+if (is == null) {
+cl = FactoryFinder.class.getClassLoader();
+is = ss.getResourceAsStream(cl, serviceId);
+}
+} else {
+// No Context ClassLoader, try the current ClassLoader
+cl = FactoryFinder.class.getClassLoader();
+is = ss.getResourceAsStream(cl, serviceId);
+}
+if (is == null) {
+// No provider found
+return null;
+}
+if (debug) {    // Extra check to avoid computing cl strings
+dPrint("found jar resource=" + serviceId + " using ClassLoader: " + cl);
+}
+BufferedReader rd;
+try {
+rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
+}
+catch (java.io.UnsupportedEncodingException e) {
+rd = new BufferedReader(new InputStreamReader(is));
+}
+String factoryClassName = null;
+try {
+// XXX Does not handle all possible input as specified by the
+// Jar Service Provider specification
+factoryClassName = rd.readLine();
+rd.close();
+} catch (IOException x) {
+// No provider found
+return null;
+}
+if (factoryClassName != null && !"".equals(factoryClassName)) {
+dPrint("found in resource, value=" + factoryClassName);
+// Note: here we do not want to fall back to the current
+// ClassLoader because we want to avoid the case where the
+// resource file was found using one ClassLoader and the
+// provider class was instantiated using a different one.
+return newInstance(factoryClassName, cl, false);
+}
+// No provider found
+return null;
+}
+static class ConfigurationError extends Error {
+private Exception exception;
+/**
+* Construct a new instance with the specified detail string and
+* exception.
+*/
+ConfigurationError(String msg, Exception x) {
+super(msg);
+this.exception = x;
+}
+Exception getException() {
+return exception;
+}
+/**
+* use the exception chaining mechanism of JDK1.4
+*/
+@Override
+public Throwable getCause() {
+return exception;
+}
+}
+}