package org.apache.ojb.broker.core.proxy;

 /* Copyright 2002-2005 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.ref.SoftReference;

 import java.lang.ref.WeakReference;

 import java.lang.ref.Reference;

 import org.apache.ojb.broker.PBFactoryException;

 /**

  * ProxyHelper used to get the real thing behind a proxy

  *

  * @author <a href="mailto:jbraeuchi@hotmail.com">Jakob Braeuchi</a>

  * @version $Id: ProxyHelper.java,v 1.1 2007-08-24 22:17:32 ewestfal Exp $

  */

 public class ProxyHelper

 {

     private static Reference proxyFactoryRef;

     public synchronized static ProxyFactory getProxyFactory()

     {

         if((proxyFactoryRef == null) || (proxyFactoryRef.get() == null))

         {

             try

             {

                 /*

                 TODO: Check usage of WeakReference

                 arminw: Changed Soft- to WeakReference. If in AbstractProxyFactory the

                 the ProxyFactory instance is freed this class will take care of that.

                 */

                 proxyFactoryRef = new WeakReference(AbstractProxyFactory.getProxyFactory());

             }

             catch(PBFactoryException ex)

             {

                 // seems we cannot get a broker; in that case we're defaulting to the CGLib proxy factory

                 // (which also works for older JDKs) ie. for broker-less mode (only metadata)

                 return new ProxyFactoryCGLIBImpl();

             }

         }

         return (ProxyFactory) proxyFactoryRef.get();

     }

     /**

      * Get the real Object

      *

      * @param objectOrProxy

      * @return Object

      */

     public static final Object getRealObject(Object objectOrProxy)

     {

         return getProxyFactory().getRealObject(objectOrProxy);

     }

     /**

      * Get the real Object for already materialized Handler

      *

      * @param objectOrProxy

      * @return Object or null if the Handel is not materialized

      */

     public static final Object getRealObjectIfMaterialized(Object objectOrProxy)

     {

         return getProxyFactory().getRealObjectIfMaterialized(objectOrProxy);

     }

     /**

      * Get the real Class

      *

      * @param objectOrProxy

      * @return Class

      */

     public static final Class getRealClass(Object objectOrProxy)

     {

         return getProxyFactory().getRealClass(objectOrProxy);

     }

     /**

      * Determines whether the given object is an OJB proxy.

      *

      * @return <code>true</code> if the object is an OJB proxy

      */

     public static boolean isNormalOjbProxy(Object proxyOrObject)

     {

         return getProxyFactory().isNormalOjbProxy(proxyOrObject);

     }

     /**

      * Determines whether the given object is an OJB virtual proxy.

      *

      * @return <code>true</code> if the object is an OJB virtual proxy

      */

     public static boolean isVirtualOjbProxy(Object proxyOrObject)

     {

         return getProxyFactory().isVirtualOjbProxy(proxyOrObject);

     }

     /**

      * Returns <tt>true</tt> if the given object is a {@link java.lang.reflect.Proxy}

      * or a {@link VirtualProxy} instance.

      */

     public static boolean isProxy(Object proxyOrObject)

     {

         return getProxyFactory().isProxy(proxyOrObject);

     }

     /**

      * Returns the invocation handler object of the given proxy object.

      *

      * @param obj The object

      * @return The invocation handler if the object is an OJB proxy, or <code>null</code>

      *         otherwise

      */

     public static IndirectionHandler getIndirectionHandler(Object obj)

     {

         return getProxyFactory().getIndirectionHandler(obj);

     }

     /**

      * Determines whether the object is a materialized object, i.e. no proxy or a

      * proxy that has already been loaded from the database.

      *

      * @param object The object to test

      * @return <code>true</code> if the object is materialized

      */

     public static boolean isMaterialized(Object object)

     {

         return getProxyFactory().isMaterialized(object);

     }

     /**

      * Materialization-safe version of toString. If the object is a yet-unmaterialized proxy,

      * then only the text "unmaterialized proxy for ..." is returned and the proxy is NOT

      * materialized. Otherwise, the normal toString method is called. This useful e.g. for

      * logging etc.

      *

      * @param object The object for which a string representation shall be generated

      * @return The string representation

      */

     public static String toString(Object object)

     {

         return getProxyFactory().toString(object);

     }

     /** Return CollectionProxy for item is item is a CollectionProxy, otherwise return null */

     public static CollectionProxy getCollectionProxy(Object item)

     {

         return getProxyFactory().getCollectionProxy(item);

     }

     /** Reports if item is a CollectionProxy. */

     public static boolean isCollectionProxy(Object item)

     {

         // TODO: Provide handling for pluggable collection proxy implementations

         return getProxyFactory().isCollectionProxy(item);

     }

 }