common-smartgears-app/src/main/java/org/gcube/smartgears/ApplicationManagerProvider....

85 lines
3.2 KiB
Java

package org.gcube.smartgears;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Future;
import javassist.util.proxy.MethodHandler;
import javassist.util.proxy.ProxyFactory;
import javassist.util.proxy.ProxyObject;
import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.smartgears.annotations.ManagedBy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class ApplicationManagerProvider {
private static Logger logger = LoggerFactory.getLogger(ApplicationManagerProvider.class);
static Map<String, Map<String, Future<ApplicationManager>>> appManagerMap = new HashMap<String, Map<String, Future<ApplicationManager>>>();
private static Map<String, Class<?>> proxyClassMap = new HashMap<String, Class<?>>();
public static synchronized ApplicationManager get(){
final Class<? extends ApplicationManager> applicationManagerClass = retrieveManagerClass();
return get(applicationManagerClass);
}
public static synchronized ApplicationManager get(final Class<? extends ApplicationManager> applicationManagerClass){
Object obj;
try {
Class<?> _class = getProxyClass(applicationManagerClass);
obj = _class.newInstance();
} catch (Exception e) {
throw new RuntimeException("error creating proxy ", e);
}
MethodHandler handler = new MethodHandler() {
@Override
public Object invoke(Object self, Method thisMethod, Method proceed, Object[] args) throws Throwable {
logger.debug("context is {}", ScopeProvider.instance.get());
logger.debug("applicationManagerClass is {}",applicationManagerClass.getCanonicalName());
Future<ApplicationManager> appManagerFuture = appManagerMap.get(applicationManagerClass.getCanonicalName()).get(ScopeProvider.instance.get());
logger.debug("appmanager future is null? {}", appManagerFuture==null);
logger.debug("thisMethod is null? {}", thisMethod==null);
return thisMethod.invoke(appManagerFuture.get(), args);
}
};
((ProxyObject)obj).setHandler(handler);
return applicationManagerClass.cast(obj);
}
private static Class<?> getProxyClass(Class<? extends ApplicationManager> applicationManagerClass){
if (proxyClassMap.containsKey(applicationManagerClass.getCanonicalName()))
return proxyClassMap.get(applicationManagerClass.getCanonicalName());
ProxyFactory proxyfactory = new ProxyFactory();
proxyfactory.setSuperclass(applicationManagerClass);
Class<?> proxyClass=proxyfactory.createClass();
proxyClassMap.put(applicationManagerClass.getCanonicalName(), proxyClass);
return proxyClass;
}
private static Class<? extends ApplicationManager> retrieveManagerClass(){
String classname = Thread.currentThread().getStackTrace()[3].getClassName();
logger.trace("managed servlet caller is {}",classname);
ManagedBy annotation;
try {
annotation = Class.forName(classname).getAnnotation(ManagedBy.class);
} catch (ClassNotFoundException e) {
throw new RuntimeException("error initializing ApplicationManager",e);
}
if (annotation == null){
logger.error(" {} is not managed by an ApplicationManager", classname);
throw new RuntimeException(classname+" is not managed by an ApplicationManager");
}
return annotation.value();
}
}