package org.kuali.rice.core.cxf.interceptors;

 import org.apache.cxf.interceptor.Fault;

 import org.apache.cxf.message.Message;

 import org.apache.cxf.phase.AbstractPhaseInterceptor;

 import org.apache.cxf.phase.Phase;

 import java.lang.reflect.Field;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.List;

 import java.util.Map;

 import java.util.Set;

 /**

  * A CXF Interceptor that binds itself to the USER_LOGICAL phase to be used on inbound

  * messages.  This interceptor is invoked in the interceptor chain after unmarshalling

  * from XML to Java has occurred.  The role of this interceptor is to ensure that any

  * Collection (and specifically List, Set, or Map) used in a @WebMethod is ultimately of the

  * expected immutable type returned from the local service.

  */

 @SuppressWarnings("unused")

 public class ImmutableCollectionsInInterceptor extends AbstractPhaseInterceptor<Message> {

     /**

      * Instantiates an ImmutableCollectionsInInterceptor and adds it to the USER_LOGICAL phase.

      */

     public ImmutableCollectionsInInterceptor() {

         super(Phase.USER_LOGICAL);

     }

     @Override

     public void handleMessage(final Message message) throws Fault {

         try {

             List contents = message.getContent(List.class);

             for (Object o : contents) {

                 makeCollectionFieldsImmutable(o);

             }

         } catch (Exception e) {

             throw new Fault(e);

         }

     }

     /**

      * Accepts an object whose fields of type List, Set, or Collection need to be made immutable irrespective of field

      * visibility.  The passed in object is mutated as a result.

      *

      * @param o - The object whose List, Set, or Collection fields will be made immutable

      * @throws IllegalAccessException

      */

     @SuppressWarnings("unchecked")

     void makeCollectionFieldsImmutable(Object o) throws IllegalAccessException {

         Class<?> targetClass = o.getClass();

         for (Field f : targetClass.getDeclaredFields()) {

             f.setAccessible(true);

             if (f.getType().isAssignableFrom(List.class)) {

                 List original = (List) f.get(o);

                 if (original == null) {

                     original = Collections.emptyList();

                 }

                 List immutable = Collections.unmodifiableList(original);

                 f.set(o, immutable);

             } else if (f.getType().isAssignableFrom(Set.class)) {

                 Set original = (Set) f.get(o);

                 if (original == null) {

                     original = Collections.emptySet();

                 }

                 Set immutable = Collections.unmodifiableSet(original);

                 f.set(o, immutable);

             } else if (f.getType().isAssignableFrom(Collection.class)) {

                 Collection original = (Collection) f.get(o);

                 if (original == null) {

                     original = Collections.emptyList();

                 }

                 Collection immutable = Collections.unmodifiableCollection(original);

                 f.set(o, immutable);

             } else if (f.getType().isAssignableFrom(Map.class)) {

                 Map original = (Map) f.get(o);

                 if (original == null) {

                     original = Collections.emptyMap();

                 }

                 Map immutable = Collections.unmodifiableMap(original);

                 f.set(o, immutable);

             }

             f.setAccessible(false);

         }

     }

 }