/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited

  *

  * 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.

  */

 package org.acegisecurity.acl.basic;

 import org.springframework.util.Assert;

 import org.springframework.util.ClassUtils;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 /**

  * Simple implementation of {@link AclObjectIdentity}.<P>Uses <code>String</code>s to store the identity of the

  * domain object instance. Also offers a constructor that uses reflection to build the identity information.</p>

  */

 public class NamedEntityObjectIdentity implements AclObjectIdentity {

     //~ Instance fields ================================================================================================

     private String classname;

     private String id;

     //~ Constructors ===================================================================================================

     public NamedEntityObjectIdentity(String classname, String id) {

         Assert.hasText(classname, "classname required");

         Assert.hasText(id, "id required");

         this.classname = classname;

         this.id = id;

     }

 /**

      * Creates the <code>NamedEntityObjectIdentity</code> based on the passed

      * object instance. The passed object must provide a <code>getId()</code>

      * method, otherwise an exception will be thrown.

      *

      * @param object the domain object instance to create an identity for

      *

      * @throws IllegalAccessException

      * @throws InvocationTargetException

      * @throws IllegalArgumentException

      */

     public NamedEntityObjectIdentity(Object object) throws IllegalAccessException, InvocationTargetException {

         Assert.notNull(object, "object cannot be null");

         this.classname = (getPackageName(object.getClass().getName()) == null)

             ? ClassUtils.getShortName(object.getClass())

             : (getPackageName(object.getClass().getName()) + "." + ClassUtils.getShortName(object.getClass()));

         Class clazz = object.getClass();

         try {

             Method method = clazz.getMethod("getId", new Class[] {});

             Object result = method.invoke(object, new Object[] {});

             this.id = result.toString();

         } catch (NoSuchMethodException nsme) {

             throw new IllegalArgumentException("Object of class '" + clazz

                 + "' does not provide the required getId() method: " + object);

         }

     }

     //~ Methods ========================================================================================================

     /**

      * Important so caching operates properly.<P>Considers an object of the same class equal if it has the same

      * <code>classname</code> and <code>id</code> properties.</p>

      *

      * @param arg0 object to compare

      *

      * @return <code>true</code> if the presented object matches this object

      */

     public boolean equals(Object arg0) {

         if (arg0 == null) {

             return false;

         }

         if (!(arg0 instanceof NamedEntityObjectIdentity)) {

             return false;

         }

         NamedEntityObjectIdentity other = (NamedEntityObjectIdentity) arg0;

         if (this.getId().equals(other.getId()) && this.getClassname().equals(other.getClassname())) {

             return true;

         }

         return false;

     }

     /**

      * Indicates the classname portion of the object identity.

      *

      * @return the classname (never <code>null</code>)

      */

     public String getClassname() {

         return classname;

     }

     /**

      * Indicates the instance identity portion of the object identity.

      *

      * @return the instance identity (never <code>null</code>)

      */

     public String getId() {

         return id;

     }

     private String getPackageName(String className) {

         Assert.hasLength(className, "class name must not be empty");

         int lastDotIndex = className.lastIndexOf(".");

         if (lastDotIndex == -1) {

             return null;

         }

         return className.substring(0, lastDotIndex);

     }

     /**

      * Important so caching operates properly.

      *

      * @return the hash of the classname and id

      */

     public int hashCode() {

         StringBuffer sb = new StringBuffer();

         sb.append(this.classname).append(this.id);

         return sb.toString().hashCode();

     }

     public String toString() {

         StringBuffer sb = new StringBuffer();

         sb.append(this.getClass().getName()).append("[");

         sb.append("Classname: ").append(this.classname);

         sb.append("; Identity: ").append(this.id).append("]");

         return sb.toString();

     }

 }