--- old/src/javax/xml/stream/FactoryFinder.java 2013-01-09 17:34:34.000000000 +0100
+++ new/src/javax/xml/stream/FactoryFinder.java 2013-01-09 17:34:34.000000000 +0100
@@ -25,14 +25,13 @@
package javax.xml.stream;
-import java.io.InputStream;
-import java.io.IOException;
import java.io.File;
-import java.io.FileInputStream;
-
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.Iterator;
import java.util.Properties;
-import java.io.BufferedReader;
-import java.io.InputStreamReader;
+import java.util.ServiceConfigurationError;
+import java.util.ServiceLoader;
/**
* Implements pluggable Datatypes.
@@ -52,19 +51,19 @@
/**
* Cache for properties in java.home/lib/jaxp.properties
*/
- static Properties cacheProps = new Properties();
+ final private static Properties cacheProps = new Properties();
/**
* Flag indicating if properties from java.home/lib/jaxp.properties
* have been cached.
*/
- static volatile boolean firstTime = true;
+ private static volatile boolean firstTime = true;
/**
* Security support class use to check access control before
* getting certain system resources.
*/
- static SecuritySupport ss = new SecuritySupport();
+ final private static SecuritySupport ss = new SecuritySupport();
// Define system property "jaxp.debug" to get output
static {
@@ -105,17 +104,17 @@
throw new ClassNotFoundException();
}
else {
- return cl.loadClass(className);
+ return Class.forName(className, false, cl);
}
}
else {
- return cl.loadClass(className);
+ return Class.forName(className, false, cl);
}
}
catch (ClassNotFoundException e1) {
if (doFallback) {
// Use current class loader - should always be bootstrap CL
- return Class.forName(className, true, FactoryFinder.class.getClassLoader());
+ return Class.forName(className, false, FactoryFinder.class.getClassLoader());
}
else {
throw e1;
@@ -127,6 +126,9 @@
* Create an instance of a class. Delegates to method
* getProviderClass() in order to load the class.
*
+ * @param type Base class / Service interface of the factory to
+ * instantiate.
+ *
* @param className Name of the concrete class corresponding to the
* service provider
*
@@ -136,24 +138,29 @@
* @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
+ static T newInstance(Class type, String className, ClassLoader cl,
+ boolean doFallback)
+ throws FactoryConfigurationError
{
+ assert type != null;
try {
- Class providerClass = getProviderClass(className, cl, doFallback);
+ Class providerClass = getProviderClass(className, cl, doFallback);
+ if (!type.isAssignableFrom(providerClass)) {
+ throw new ClassCastException(className + " cannot be cast to " + type.getName());
+ }
Object instance = providerClass.newInstance();
if (debug) { // Extra check to avoid computing cl strings
dPrint("created new instance of " + providerClass +
" using ClassLoader: " + cl);
}
- return instance;
+ return type.cast(instance);
}
catch (ClassNotFoundException x) {
- throw new ConfigurationError(
+ throw new FactoryConfigurationError(
"Provider " + className + " not found", x);
}
catch (Exception x) {
- throw new ConfigurationError(
+ throw new FactoryConfigurationError(
"Provider " + className + " could not be instantiated: " + x,
x);
}
@@ -164,17 +171,18 @@
*
* @return Class object of factory, never null
*
- * @param factoryId Name of the factory to find, same as
- * a property name
+ * @param type Base class / Service interface of the
+ * factory to find.
+ *
* @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
+ static T find(Class type, String fallbackClassName)
+ throws FactoryConfigurationError
{
- return find(factoryId, null, fallbackClassName);
+ return find(type, type.getName(), null, fallbackClassName);
}
/**
@@ -182,6 +190,9 @@
* entry point.
* @return Class object of factory, never null
*
+ * @param type Base class / Service interface of the
+ * factory to find.
+ *
* @param factoryId Name of the factory to find, same as
* a property name
*
@@ -193,8 +204,8 @@
*
* Package private so this code can be shared.
*/
- static Object find(String factoryId, ClassLoader cl, String fallbackClassName)
- throws ConfigurationError
+ static T find(Class type, String factoryId, ClassLoader cl, String fallbackClassName)
+ throws FactoryConfigurationError
{
dPrint("find factoryId =" + factoryId);
@@ -203,7 +214,9 @@
String systemProp = ss.getSystemProperty(factoryId);
if (systemProp != null) {
dPrint("found system property, value=" + systemProp);
- return newInstance(systemProp, null, true);
+ // There's a bug here - because 'cl' is ignored.
+ // This will be handled separately.
+ return newInstance(type, systemProp, null, true);
}
}
catch (SecurityException se) {
@@ -214,7 +227,7 @@
// $java.home/lib/jaxp.properties if former not present
String configFile = null;
try {
- String factoryClassName = null;
+ String factoryClassName;
if (firstTime) {
synchronized (cacheProps) {
if (firstTime) {
@@ -242,117 +255,70 @@
if (factoryClassName != null) {
dPrint("found in " + configFile + " value=" + factoryClassName);
- return newInstance(factoryClassName, null, true);
+ // There's a bug here - because 'cl' is ignored.
+ // This will be handled separately.
+ return newInstance(type, 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 (type.getName().equals(factoryId)) {
+ // Try Jar Service Provider Mechanism
+ final T provider = findServiceProvider(type);
+ if (provider != null) {
+ return provider;
+ }
+ } else {
+ // We're in the case where a 'custom' factoryId was provided,
+ // and in every case where that happens, we expect that
+ // fallbackClassName will be null.
+ assert fallbackClassName == null;
}
+
if (fallbackClassName == null) {
- throw new ConfigurationError(
+ throw new FactoryConfigurationError(
"Provider for " + factoryId + " cannot be found", null);
}
dPrint("loaded from fallback value: " + fallbackClassName);
- return newInstance(fallbackClassName, cl, true);
+ return newInstance(type, fallbackClassName, cl, true);
}
/*
- * Try to find provider using Jar Service Provider Mechanism
+ * Try to find provider using the ServiceLoader API
+ *
+ * @param type Base class / Service interface of the factory to find.
*
* @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;
+ private static T findServiceProvider(final Class type) {
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;
+ return AccessController.doPrivileged(new PrivilegedAction() {
+ public T run() {
+ final ServiceLoader serviceLoader = ServiceLoader.load(type);
+ final Iterator iterator = serviceLoader.iterator();
+ if (iterator.hasNext()) {
+ return iterator.next();
+ } else {
+ return null;
+ }
+ }
+ });
+ } catch(ServiceConfigurationError e) {
+ // It is not possible to wrap an error directly in
+ // FactoryConfigurationError - so we need to wrap the
+ // ServiceConfigurationError in a RuntimeException.
+ // The alternative would be to modify the logic in
+ // FactoryConfigurationError to allow setting a
+ // Throwable as the cause, but that could cause
+ // compatibility issues down the road.
+ final RuntimeException x = new RuntimeException(
+ "Provider for " + type + " cannot be created", e);
+ final FactoryConfigurationError error =
+ new FactoryConfigurationError(x, x.getMessage());
+ throw error;
}
}