package org.hibernate.validation.engine.resolver;
import java.lang.annotation.ElementType;
import java.security.AccessController;
import javax.validation.Path;
import javax.validation.TraversableResolver;
import javax.validation.ValidationException;
import org.slf4j.Logger;
import org.hibernate.validation.util.LoggerFactory;
import org.hibernate.validation.util.ReflectionHelper;
import org.hibernate.validation.util.NewInstance;
import org.hibernate.validation.util.LoadClass;
/**
* A JPA 2 aware <code>TraversableResolver</code>.
*
* @author Emmanuel Bernard
* @author Hardy Ferentschik
*/
public class DefaultTraversableResolver implements TraversableResolver {
private static final Logger log = LoggerFactory.make();
/**
* Class to load to check whether JPA 2 is on the classpath.
*/
private static final String PERSISTENCE_UTIL_CLASS_NAME = "javax.persistence.PersistenceUtil";
/**
* Class to instantiate in case JPA 2 is on the classpath.
*/
private static final String JPA_AWARE_TRAVERSABLE_RESOLVER_CLASS_NAME = "org.hibernate.validation.engine.resolver.JPATraversableResolver";
/**
* A JPA 2 aware traversable resolver.
*/
private TraversableResolver jpaTraversableResolver;
public DefaultTraversableResolver() {
detectJPA();
}
/**
* Tries to load detect and load JPA.
*/
private void detectJPA() {
try {
loadClass( PERSISTENCE_UTIL_CLASS_NAME, this.getClass() );
log.debug( "Found {} on classpath.", PERSISTENCE_UTIL_CLASS_NAME );
}
catch ( ValidationException e ) {
log.debug(
"Cannot find {} on classpath. All properties will per default be traversable.",
PERSISTENCE_UTIL_CLASS_NAME
);
return;
}
try {
@SuppressWarnings( "unchecked" )
Class<? extends TraversableResolver> jpaAwareResolverClass = (Class<? extends TraversableResolver>)
loadClass(JPA_AWARE_TRAVERSABLE_RESOLVER_CLASS_NAME, this.getClass() );
NewInstance<? extends TraversableResolver> newInstance = NewInstance.action( jpaAwareResolverClass, "" );
if ( System.getSecurityManager() != null ) {
jpaTraversableResolver = AccessController.doPrivileged( newInstance );
}
else {
jpaTraversableResolver = newInstance.run();
}
log.info(
"Instantiated an instance of {}.", JPA_AWARE_TRAVERSABLE_RESOLVER_CLASS_NAME
);
}
catch ( ValidationException e ) {
log.info(
"Unable to load or instanciate JPA aware resolver {}. All properties will per default be traversable.",
JPA_AWARE_TRAVERSABLE_RESOLVER_CLASS_NAME
);
}
}
private Class<?> loadClass(String className, Class<?> caller) {
LoadClass action = LoadClass.action( className, caller );
if (System.getSecurityManager() != null) {
return AccessController.doPrivileged( action );
}
else {
return action.run();
}
}
public boolean isReachable(Object traversableObject, Path.Node traversableProperty, Class<?> rootBeanType, Path pathToTraversableObject, ElementType elementType) {
return jpaTraversableResolver == null || jpaTraversableResolver.isReachable(
traversableObject, traversableProperty, rootBeanType, pathToTraversableObject, elementType
);
}
public boolean isCascadable(Object traversableObject, Path.Node traversableProperty, Class<?> rootBeanType, Path pathToTraversableObject, ElementType elementType) {
return jpaTraversableResolver == null || jpaTraversableResolver.isCascadable(
traversableObject, traversableProperty, rootBeanType, pathToTraversableObject, elementType
);
}
}