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package com.sun.tools.internal.xjc.runtime;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
This class implements the actual logic of JAXBContext.newInstance.
This class works as a facade and all the actual work is delegated to
a JAXB provider that happens to be in the runtime (not necessarily the JAXB RI.)
This allows the generated code to be run with any JAXB provider.
This code is only used when XJC generates interfaces/implementations.
The trick to make this work is two ObjectFactory classes that we generate
in the interface/implementation mode.
The public ObjectFactory follows the spec, and this is the one that's exposed
to users. The public ObjectFactory refers to interfaces, so they aren't
directly usable by a JAXB 2.0 implementation.
The private one lives in the impl package, and this one is indistinguishable
from the ObjectFactory that we generate for the value class generation mode.
This private ObjectFactory refers to implementation classes, which are
also indistinguishable from value classes that JAXB generates.
All in all, the private ObjectFactory plus implementation classes give
a JAXB provider an illusion that they are dealing with value classes
that happens to implement some interfaces.
In this way, the JAXB RI can provide the portability even for the
interface/implementation generation mode.
Author: Kohsuke Kawaguchi Since: 2.0
/**
* This class implements the actual logic of {@link JAXBContext#newInstance}.
*
* <p>
* This class works as a facade and all the actual work is delegated to
* a JAXB provider that happens to be in the runtime (not necessarily the JAXB RI.)
* This allows the generated code to be run with any JAXB provider.
*
* <p>
* This code is only used when XJC generates interfaces/implementations.
*
* <p>
* The trick to make this work is two ObjectFactory classes that we generate
* in the interface/implementation mode.
*
* <p>
* The public ObjectFactory follows the spec, and this is the one that's exposed
* to users. The public ObjectFactory refers to interfaces, so they aren't
* directly usable by a JAXB 2.0 implementation.
*
* <p>
* The private one lives in the impl package, and this one is indistinguishable
* from the ObjectFactory that we generate for the value class generation mode.
* This private ObjectFactory refers to implementation classes, which are
* also indistinguishable from value classes that JAXB generates.
*
* <p>
* All in all, the private ObjectFactory plus implementation classes give
* a JAXB provider an illusion that they are dealing with value classes
* that happens to implement some interfaces.
*
* <p>
* In this way, the JAXB RI can provide the portability even for the
* interface/implementation generation mode.
*
* @since 2.0
* @author Kohsuke Kawaguchi
*/
public class JAXBContextFactory {
private static final String DOT_OBJECT_FACTORY = ".ObjectFactory";
private static final String IMPL_DOT_OBJECT_FACTORY = ".impl.ObjectFactory";
The JAXB API will invoke this method via reflection
/**
* The JAXB API will invoke this method via reflection
*/
public static JAXBContext createContext( Class[] classes, Map properties ) throws JAXBException {
Class[] r = new Class[classes.length];
boolean modified = false;
// find any reference to our 'public' ObjectFactory and
// replace that to our 'private' ObjectFactory.
for( int i=0; i<r.length; i++ ) {
Class c = classes[i];
String name = c.getName();
if(name.endsWith(DOT_OBJECT_FACTORY)
&& !name.endsWith(IMPL_DOT_OBJECT_FACTORY)) {
// we never generate into the root package, so no need to worry about FQCN "ObjectFactory"
// if we find one, tell the real JAXB provider to
// load foo.bar.impl.ObjectFactory
name = name.substring(0,name.length()-DOT_OBJECT_FACTORY.length())+IMPL_DOT_OBJECT_FACTORY;
try {
c = getClassClassLoader(c).loadClass(name);
} catch (ClassNotFoundException e) {
throw new JAXBException(e);
}
modified = true;
}
r[i] = c;
}
if(!modified) {
// if the class list doesn't contain any of our classes,
// this ContextFactory shouldn't have been called in the first place
// if we simply continue, we'll just end up with the infinite recursion.
// the only case that I can think of where this could happen is
// when the user puts additional classes into the JAXB-generated
// package and pass them to JAXBContext.newInstance().
// Under normal use, this shouldn't happen.
// anyway, bail out now.
// if you hit this problem and wondering how to get around the problem,
// subscribe and send a note to users@jaxb.dev.java.net (http://jaxb.dev.java.net/)
throw new JAXBException("Unable to find a JAXB implementation to delegate");
}
// delegate to the JAXB provider in the system
return JAXBContext.newInstance(r,properties);
}
The JAXB API will invoke this method via reflection
/**
* The JAXB API will invoke this method via reflection
*/
public static JAXBContext createContext( String contextPath,
ClassLoader classLoader, Map properties ) throws JAXBException {
List<Class> classes = new ArrayList<Class>();
StringTokenizer tokens = new StringTokenizer(contextPath,":");
// each package should be pointing to a JAXB RI generated
// content interface package.
//
// translate them into a list of private ObjectFactories.
try {
while(tokens.hasMoreTokens()) {
String pkg = tokens.nextToken();
classes.add(classLoader.loadClass(pkg+IMPL_DOT_OBJECT_FACTORY));
}
} catch (ClassNotFoundException e) {
throw new JAXBException(e);
}
// delegate to the JAXB provider in the system
return JAXBContext.newInstance(classes.toArray(new Class[classes.size()]),properties);
}
private static ClassLoader getClassClassLoader(final Class c) {
if (System.getSecurityManager() == null) {
return c.getClassLoader();
} else {
return (ClassLoader) java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
public java.lang.Object run() {
return c.getClassLoader();
}
});
}
}
}