/* 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.acls.objectidentity;

 import org.acegisecurity.acls.IdentityUnavailableException;

 import org.springframework.util.Assert;

 import org.springframework.util.ReflectionUtils;

 import java.io.Serializable;

 import java.lang.reflect.Method;

 /**

  * Simple implementation of {@link org.acegisecurity.acl.basic.AclObjectIdentity 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 ObjectIdentityImpl implements ObjectIdentity {

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

     private Class javaType;

     private Serializable identifier;

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

     public ObjectIdentityImpl(String javaType, Serializable identifier) {

         Assert.hasText(javaType, "Java Type required");

         Assert.notNull(identifier, "identifier required");

         try {

             this.javaType = Class.forName(javaType);

         } catch (Exception ex) {

             ReflectionUtils.handleReflectionException(ex);

         }

         this.identifier = identifier;

     }

     public ObjectIdentityImpl(Class javaType, Serializable identifier) {

         Assert.notNull(javaType, "Java Type required");

         Assert.notNull(identifier, "identifier required");

         this.javaType = javaType;

         this.identifier = identifier;

     }

 /**

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

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

      * method, otherwise an exception will be thrown. The object passed will

      * be considered the {@link #javaType}, so if more control is required,

      * an alternate constructor should be used instead.

      *

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

      *

      * @throws IdentityUnavailableException if identity could not be extracted

      */

     public ObjectIdentityImpl(Object object) throws IdentityUnavailableException {

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

         this.javaType = object.getClass();

         Object result;

         try {

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

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

         } catch (Exception e) {

             throw new IdentityUnavailableException("Could not extract identity from object " + object, e);

         }

         Assert.notNull(result, "getId() is required to return a non-null value");

         Assert.isInstanceOf(Serializable.class, result, "Getter must provide a return value of type Serializable");

         this.identifier = (Serializable) result;

     }

     //~ 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 ObjectIdentityImpl)) {

             return false;

         }

         ObjectIdentityImpl other = (ObjectIdentityImpl) arg0;

         if (this.getIdentifier().equals(other.getIdentifier()) && this.getJavaType().equals(other.getJavaType())) {

             return true;

         }

         return false;

     }

     public Serializable getIdentifier() {

         return identifier;

     }

     public Class getJavaType() {

         return javaType;

     }

     /**

      * Important so caching operates properly.

      *

      * @return the hash

      */

     public int hashCode() {

         int code = 31;

         code ^= this.javaType.hashCode();

         code ^= this.identifier.hashCode();

         return code;

     }

     public String toString() {

         StringBuffer sb = new StringBuffer();

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

         sb.append("Java Type: ").append(this.javaType);

         sb.append("; Identifier: ").append(this.identifier).append("]");

         return sb.toString();

     }

 }