/* 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.runas;

 import org.acegisecurity.AcegiMessageSource;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.AuthenticationException;

 import org.acegisecurity.BadCredentialsException;

 import org.acegisecurity.providers.AuthenticationProvider;

 import org.springframework.beans.factory.InitializingBean;

 import org.springframework.context.MessageSource;

 import org.springframework.context.MessageSourceAware;

 import org.springframework.context.support.MessageSourceAccessor;

 import org.springframework.util.Assert;

 /**

  * An {@link AuthenticationProvider} implementation that can authenticate a {@link RunAsUserToken}.<P>Configured in

  * the bean context with a key that should match the key used by adapters to generate the <code>RunAsUserToken</code>.

  * It treats as valid any <code>RunAsUserToken</code> instance presenting a hash code that matches the

  * <code>RunAsImplAuthenticationProvider</code>-configured key.</p>

  *  <P>If the key does not match, a <code>BadCredentialsException</code> is thrown.</p>

  */

 public class RunAsImplAuthenticationProvider implements InitializingBean, AuthenticationProvider, MessageSourceAware {

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

     protected MessageSourceAccessor messages = AcegiMessageSource.getAccessor();

     private String key;

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

         public void afterPropertiesSet() throws Exception {

         Assert.notNull(key, "A Key is required and should match that configured for the RunAsManagerImpl");

     }

     public Authentication authenticate(Authentication authentication)

         throws AuthenticationException {

         RunAsUserToken token = (RunAsUserToken) authentication;

         if (token.getKeyHash() == key.hashCode()) {

             return authentication;

         } else {

             throw new BadCredentialsException(messages.getMessage("RunAsImplAuthenticationProvider.incorrectKey",

                     "The presented RunAsUserToken does not contain the expected key"));

         }

     }

     public String getKey() {

         return key;

     }

     public void setKey(String key) {

         this.key = key;

     }

     public void setMessageSource(MessageSource messageSource) {

         this.messages = new MessageSourceAccessor(messageSource);

     }

     public boolean supports(Class authentication) {

         if (RunAsUserToken.class.isAssignableFrom(authentication)) {

             return true;

         } else {

             return false;

         }

     }

 }