package org.apache.ojb.otm.swizzle;

 /* Copyright 2003-2005 The Apache Software Foundation

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 import java.lang.reflect.Array;

 import java.util.Collection;

 import java.util.Iterator;

 import java.util.List;

 import java.util.Set;

 import org.apache.ojb.broker.Identity;

 import org.apache.ojb.broker.PersistenceBroker;

 import org.apache.ojb.broker.cache.ObjectCache;

 import org.apache.ojb.broker.core.proxy.CollectionProxyDefaultImpl;

 import org.apache.ojb.broker.core.proxy.ListProxyDefaultImpl;

 import org.apache.ojb.broker.core.proxy.SetProxyDefaultImpl;

 import org.apache.ojb.broker.metadata.ClassDescriptor;

 import org.apache.ojb.broker.metadata.CollectionDescriptor;

 import org.apache.ojb.broker.metadata.FieldDescriptor;

 import org.apache.ojb.broker.metadata.ObjectReferenceDescriptor;

 import org.apache.ojb.broker.metadata.fieldaccess.PersistentField;

 public class CopySwizzling implements Swizzling

 {

     /**

      * @see org.apache.ojb.otm.swizzle.Swizzling#swizzle(Object, Object, PersistenceBroker, ObjectCache)

      */

     public Object swizzle(Object newObj, Object oldObj, PersistenceBroker pb,

                           ObjectCache cache)

     {

         if (newObj == null) // invalidating

         {

             return null;

         }

         if (oldObj == null)

         {

             return newObj;

         }

         if (!newObj.getClass().equals(oldObj.getClass()))

         {

             System.err.println("Cannot swizzle objects of different classes: "

                     + newObj.getClass() + " and " + oldObj.getClass());

             return newObj;

         }

         ClassDescriptor mif = pb.getClassDescriptor(newObj.getClass());

         FieldDescriptor[] fieldDescs = mif.getFieldDescriptions();

         for (int i = 0; i < fieldDescs.length; i++)

         {

             FieldDescriptor fd = fieldDescs[i];

             PersistentField f = fd.getPersistentField();

             f.set(oldObj, f.get(newObj));

         }

         // N:1 relations

         Iterator iter = mif.getObjectReferenceDescriptors().iterator();

         ObjectReferenceDescriptor rds;

         PersistentField field;

         Object newRelObj;

         Identity newRelOid;

         Object oldRelObj;

         while (iter.hasNext())

         {

             rds = (ObjectReferenceDescriptor) iter.next();

             field = rds.getPersistentField();

             newRelObj = field.get(newObj);

             oldRelObj = field.get(oldObj);

             if ((newRelObj == null) && (oldRelObj != null))

             {

                 field.set(oldObj, null);

             }

             else if (newRelObj != null)

             {

                 newRelOid = new Identity(newRelObj, pb);

                 if ((oldRelObj == null) ||

                         !newRelOid.equals(new Identity(oldRelObj, pb)))

                 {

                     // seek for existing old object with the new identity

                     oldRelObj = cache.lookup(newRelOid);

                     if (oldRelObj == null)

                     {

                         throw new IllegalStateException("Related object not found in the context: " + newRelOid);

                     }

                     field.set(oldObj, oldRelObj);

                 }

             }

         }

         // 1:N relations

         Iterator collections = mif.getCollectionDescriptors().iterator();

         CollectionDescriptor collectionDescriptor;

         while (collections.hasNext())

         {

             collectionDescriptor = (CollectionDescriptor) collections.next();

             field = collectionDescriptor.getPersistentField();

             if (Collection.class.isAssignableFrom(field.getType()))

             {

                 Collection newCol;

                 Collection oldCol;

                 newCol = (Collection) field.get(newObj);

                 if (newCol == null)

                 {

                     field.set(oldObj, null);

                     continue;

                 }

                 oldCol = (Collection) field.get(oldObj);

                 if (newCol instanceof CollectionProxyDefaultImpl)

                 {

                     CollectionProxyDefaultImpl cp = (CollectionProxyDefaultImpl) newCol;

                     if (newCol instanceof List)

                     {

                         oldCol = new ListProxyDefaultImpl(pb.getPBKey(), cp.getCollectionClass(), cp.getQuery());

                     }

                     else if (newCol instanceof Set)

                     {

                         oldCol = new SetProxyDefaultImpl(pb.getPBKey(), cp.getCollectionClass(), cp.getQuery());

                     }

                     else

                     {

                         oldCol = new CollectionProxyDefaultImpl(pb.getPBKey(), cp.getCollectionClass(), cp.getQuery());

                     }

                     if (!((CollectionProxyDefaultImpl) newCol).isLoaded())

                     {

                         field.set(oldObj, oldCol);

                         continue;

                     }

                     oldCol.clear();

                 }

                 else

                 {

                     try

                     {

                         oldCol = (Collection) newCol.getClass().newInstance();

                     }

                     catch (Exception ex)

                     {

                         System.err.println("Cannot instantiate collection field which is neither Collection nor array: " + field);

                         ex.printStackTrace();

                         return newObj;

                     }

                 }

                 field.set(oldObj, oldCol);

                 for (Iterator it = newCol.iterator(); it.hasNext(); )

                 {

                     newRelObj = it.next();

                     newRelOid = new Identity(newRelObj, pb);

                     oldRelObj = cache.lookup(newRelOid);

                     if (oldRelObj == null)

                     {

                         oldRelObj = newRelObj;

                     }

                     oldCol.add(oldRelObj);

                 }

             }

             else if (field.getType().isArray())

             {

                 Object newArray = field.get(newObj);

                 int length = Array.getLength(newArray);

                 Object oldArray =

                         Array.newInstance(field.getType().getComponentType(), length);

                 for (int i = 0; i < length; i++)

                 {

                     newRelObj = Array.get(newArray, i);

                     newRelOid = new Identity(newRelObj, pb);

                     oldRelObj = cache.lookup(newRelOid);

                     if (oldRelObj == null)

                     {

                         throw new IllegalStateException("Related object not found for swizzle: " + newRelOid);

                     }

                     Array.set(oldArray, i, oldRelObj);

                 }

                 field.set(oldObj, oldArray);

             }

             else

             {

                 throw new IllegalStateException("Cannot swizzle collection field: " + field);

             }

         }

         return oldObj;

     }

     /**

      * @see org.apache.ojb.otm.swizzle.Swizzling#isSameInstance(Object, Object)

      */

     public boolean isSameInstance(Object swizzledObject, Object object)

     {

         return (swizzledObject == object);

     }

     /**

      * @see org.apache.ojb.otm.swizzle.Swizzling#getRealTarget(Object)

      */

     public Object getRealTarget(Object swizzledObject)

     {

         return swizzledObject;

     }

 }