javax.xml.rpc.FactoryFinder Maven / Gradle / Ivy
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.xml.rpc;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Properties;
/**
* This code is designed to implement the pluggability
* feature and is designed to both compile and run on JDK version 1.1 and
* later. The code also runs both as part of an unbundled jar file and
* when bundled as part of the JDK.
*
* This class is duplicated for each subpackage so keep it in sync.
* It is package private and therefore is not exposed as part of the JAXRPC
* API.
*/
class FactoryFinder {
/** Set to true for debugging. */
private static final boolean debug = false;
private static void debugPrintln(String msg) {
if (debug) {
System.err.println("JAXRPC: " + msg);
}
}
/**
* Figure out which ClassLoader to use. For JDK 1.2 and later use
* the context ClassLoader.
*
* @return the ClassLoader
* @throws ConfigurationError if this class is unable to work with the
* host JDK
*/
private static ClassLoader findClassLoader()
throws ConfigurationError
{
Method m = null;
try {
m = Thread.class.getMethod("getContextClassLoader", null);
} catch (NoSuchMethodException e) {
// Assume that we are running JDK 1.1, use the current ClassLoader
debugPrintln("assuming JDK 1.1");
return FactoryFinder.class.getClassLoader();
}
try {
return (ClassLoader) m.invoke(Thread.currentThread(), null);
} catch (IllegalAccessException e) {
// assert(false)
throw new ConfigurationError("Unexpected IllegalAccessException",
e);
} catch (InvocationTargetException e) {
// assert(e.getTargetException() instanceof SecurityException)
throw new ConfigurationError("Unexpected InvocationTargetException",
e);
}
}
/**
* Create an instance of a class using the specified
* ClassLoader, or if that fails from the
* ClassLoader that loaded this class.
*
* @param className the name of the class to instantiate
* @param classLoader a ClassLoader to load the class from
*
* @return a new Object that is an instance of the class of
* the given name from the given class loader
* @throws ConfigurationError if the class could not be found or
* instantiated
*/
private static Object newInstance(String className,
ClassLoader classLoader)
throws ConfigurationError
{
try {
if (classLoader != null) {
try {
return classLoader.loadClass(className).newInstance ();
} catch (ClassNotFoundException x) {
// try again
}
}
return Class.forName(className).newInstance();
} 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.
*
* @exception FactoryFinder.ConfigurationError
*
* Package private so this code can be shared.
*/
static Object find(String factoryId, String fallbackClassName)
throws ConfigurationError
{
debugPrintln("debug is on");
ClassLoader classLoader = findClassLoader();
// Use the system property first
try {
String systemProp =
System.getProperty( factoryId );
if( systemProp!=null) {
debugPrintln("found system property " + systemProp);
return newInstance(systemProp, classLoader);
}
} catch (SecurityException se) {
}
// try to read from $java.home/lib/xml.properties
try {
String javah=System.getProperty( "java.home" );
String configFile = javah + File.separator +
"lib" + File.separator + "jaxrpc.properties";
File f=new File( configFile );
if( f.exists()) {
Properties props=new Properties();
props.load( new FileInputStream(f));
String factoryClassName = props.getProperty(factoryId);
debugPrintln("found java.home property " + factoryClassName);
return newInstance(factoryClassName, classLoader);
}
} catch(Exception ex ) {
if( debug ) ex.printStackTrace();
}
String serviceId = "META-INF/services/" + factoryId;
// try to find services in CLASSPATH
try {
InputStream is=null;
if (classLoader == null) {
is=ClassLoader.getSystemResourceAsStream( serviceId );
} else {
is=classLoader.getResourceAsStream( serviceId );
}
if( is!=null ) {
debugPrintln("found " + serviceId);
// Read the service provider name in UTF-8 as specified in
// the jar spec. Unfortunately this fails in Microsoft
// VJ++, which does not implement the UTF-8
// encoding. Theoretically, we should simply let it fail in
// that case, since the JVM is obviously broken if it
// doesn't support such a basic standard. But since there
// are still some users attempting to use VJ++ for
// development, we have dropped in a fallback which makes a
// second attempt using the platform's default encoding. In
// VJ++ this is apparently ASCII, which is a subset of
// UTF-8... and since the strings we'll be reading here are
// also primarily limited to the 7-bit ASCII range (at
// least, in English versions), this should work well
// enough to keep us on the air until we're ready to
// officially decommit from VJ++. [Edited comment from
// jkesselm]
BufferedReader rd;
try {
rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
} catch (java.io.UnsupportedEncodingException e) {
rd = new BufferedReader(new InputStreamReader(is));
}
String factoryClassName = rd.readLine();
rd.close();
if (factoryClassName != null &&
! "".equals(factoryClassName)) {
debugPrintln("loaded from services: " + factoryClassName);
return newInstance(factoryClassName, classLoader);
}
}
} catch( Exception ex ) {
if( debug ) ex.printStackTrace();
}
if (fallbackClassName == null) {
throw new ConfigurationError(
"Provider for " + factoryId + " cannot be found", null);
}
debugPrintln("loaded from fallback value: " + fallbackClassName);
return newInstance(fallbackClassName, classLoader);
}
static class ConfigurationError extends Error {
// fixme: should this be refactored to use the jdk1.4 exception
// wrapping?
private Exception exception;
/**
* Construct a new instance with the specified detail string and
* exception.
*
* @param msg the Message for this error
* @param x an Exception that caused this failure, or null
*/
ConfigurationError(String msg, Exception x) {
super(msg);
this.exception = x;
}
Exception getException() {
return exception;
}
}
}
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