ObjectType.java

/**
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.gatein.mop.api.workspace;

import org.gatein.mop.api.workspace.ui.UIComponent;
import org.gatein.mop.api.workspace.ui.UIWindow;
import org.gatein.mop.api.workspace.ui.UIContainer;
import org.gatein.mop.api.workspace.ui.UIBody;
import org.gatein.mop.api.workspace.link.PageLink;
import org.gatein.mop.api.workspace.link.URLLink;

import java.io.InvalidObjectException;
import java.io.Serializable;
import java.util.Set;
import java.util.HashSet;

/**
 * A type safe interface for the type of a workspace object.
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
public class ObjectType<O extends WorkspaceObject> implements Serializable
{

   /** . */
   public static final ObjectType<WorkspaceObject> ANY = new ObjectType<WorkspaceObject>(0, WorkspaceObject.class);

   /** . */
   public static final ObjectType<Workspace> WORKSPACE = new ObjectType<Workspace>(1, Workspace.class);

   /** . */
   public static final ObjectType<Site> SITE = new ObjectType<Site>(2, Site.class);

   /** . */
   public static final ObjectType<Site> PORTAL_SITE = new ObjectType<Site>(3, Site.class, SITE);

   /** . */
   public static final ObjectType<Site> GROUP_SITE = new ObjectType<Site>(4, Site.class, SITE);

   /** . */
   public static final ObjectType<Site> USER_SITE = new ObjectType<Site>(5, Site.class, SITE);

   /** . */
   public static final ObjectType<Page> PAGE = new ObjectType<Page>(6, Page.class);

   /** . */
   public static final ObjectType<Navigation> NAVIGATION = new ObjectType<Navigation>(7, Navigation.class);

   /** . */
   public static final ObjectType<UIComponent> COMPONENT = new ObjectType<UIComponent>(8, UIComponent.class);

   /** . */
   public static final ObjectType<UIBody> BODY = new ObjectType<UIBody>(9, UIBody.class, COMPONENT);

   /** . */
   public static final ObjectType<UIContainer> CONTAINER = new ObjectType<UIContainer>(10, UIContainer.class, COMPONENT);

   /** . */
   public static final ObjectType<UIWindow> WINDOW = new ObjectType<UIWindow>(11, UIWindow.class, COMPONENT);

   /** . */
   public static final ObjectType<PageLink> PAGE_LINK = new ObjectType<PageLink>(12, PageLink.class);

   /** . */
   public static final ObjectType<URLLink> URL_LINK = new ObjectType<URLLink>(13, URLLink.class);

   /** . */
   private static final ObjectType[] ENUMERATION =
   {
      ANY,
      WORKSPACE,
      SITE,
      PORTAL_SITE,
      GROUP_SITE,
      USER_SITE,
      PAGE,
      NAVIGATION,
      COMPONENT,
      BODY,
      CONTAINER,
      WINDOW,
      PAGE_LINK,
      URL_LINK
   };

   /** . */
   private final int ordinal;

   /** . */
   private final transient Class<O> javaType;

   /** . */
   private final transient Set<ObjectType<?>> superTypes;

   private ObjectType(int ordinal, Class<O> javaType, ObjectType<?>... superTypes)
   {
      for (ObjectType<?> superType : superTypes)
      {
         if (!superType.javaType.isAssignableFrom(javaType))
         {
            throw new AssertionError();
         }
      }

      //
      Set<ObjectType<?>> tmp = new HashSet<ObjectType<?>>();
      for (ObjectType<?> superType : superTypes)
      {
         tmp.add(superType);
      }

      //
      this.ordinal = ordinal;
      this.javaType = javaType;
      this.superTypes = tmp;
   }

   public Class<O> getJavaType()
   {
      return javaType;
   }

   public boolean isAssignableFrom(ObjectType<?> other)
   {
      if (other == null)
      {
         throw new NullPointerException();
      }
      if (this == ANY)
      {
         return true;
      }
      return other == this || other.superTypes.contains(this);
   }

   public O cast(Object o)
   {
      if (o == null)
      {
         return null;
      }
      if (javaType.isInstance(o))
      {
         return javaType.cast(o);
      }
      else
      {
         throw new ClassCastException();
      }
   }

   private Object readResolve () throws java.io.ObjectStreamException
   {
      if (ordinal >= 0 || ordinal < ENUMERATION.length)
      {
         return ENUMERATION[ordinal];
      }
      else
      {
         throw new InvalidObjectException("Corrupted ordinal value" + ordinal);
      }
   }

   @Override
   public String toString()
   {
      return "ObjectType[" + javaType + "]";
   }
}