package freemarker.ext.rhino;
import java.security.AccessController;
import java.security.PrivilegedExceptionAction;
import org.mozilla.javascript.Scriptable;
import org.mozilla.javascript.Undefined;
import org.mozilla.javascript.UniqueTag;
import org.mozilla.javascript.Wrapper;
import freemarker.ext.beans.BeansWrapper;
import freemarker.ext.util.ModelFactory;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.utility.UndeclaredThrowableException;
/**
* @author Attila Szegedi
* @version $Id: RhinoWrapper.java,v 1.2.2.1 2006/07/31 11:34:52 szegedia Exp $
*/
public class RhinoWrapper extends BeansWrapper {
// The type of the "instance" field changed between Rhino versions, so a
// GETSTATIC with wrong type declaration would cause a NoSuchFieldError;
// we're avoiding it by acquiring it reflectively.
private static final Object UNDEFINED_INSTANCE;
static {
try {
UNDEFINED_INSTANCE = AccessController.doPrivileged(new PrivilegedExceptionAction() {
public Object run() throws Exception {
return Undefined.class.getField("instance").get(null);
}
});
}
catch(RuntimeException e) {
throw e;
}
catch(Exception e) {
throw new UndeclaredThrowableException(e);
}
}
public TemplateModel wrap(Object obj) throws TemplateModelException {
// So our existence builtins work as expected.
if(obj == UNDEFINED_INSTANCE || obj == UniqueTag.NOT_FOUND) {
return null;
}
// UniqueTag.NULL_VALUE represents intentionally set null in Rhino, and
// BeansWrapper#nullModel also represents intentionally returned null.
// I [A.Sz.] am fairly certain that this value is never passed out of
// any of the Rhino code back to clients, but is instead always being
// converted back to null. However, since this object is available to
// any 3rd party Scriptable implementations as well, they might return
// it, so we'll just be on the safe side, and handle it.
if(obj == UniqueTag.NULL_VALUE) {
return super.wrap(null);
}
// So, say, a JavaAdapter for FreeMarker interfaces works
if(obj instanceof Wrapper) {
obj = ((Wrapper)obj).unwrap();
}
return super.wrap(obj);
}
protected ModelFactory getModelFactory(Class clazz) {
if(Scriptable.class.isAssignableFrom(clazz)) {
return RhinoScriptableModel.FACTORY;
}
return super.getModelFactory(clazz);
}
}
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