/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * 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.argeo.cms.spring;
  
  import javax.security.auth.Subject;
  import javax.security.auth.login.LoginContext;
  import javax.security.auth.login.LoginException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.argeo.cms.CmsException;
  import org.argeo.node.NodeConstants;
  
  /** Provides base method for executing code with system authorization. */
  abstract class AbstractSystemExecution {
  	private final static Log log = LogFactory.getLog(AbstractSystemExecution.class);
  	private final Subject subject = new Subject();
  
  	/** Authenticate the calling thread */
  	protected void authenticateAsSystem() {
  		ClassLoader origClassLoader = Thread.currentThread().getContextClassLoader();
  		Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
  		try {
  			LoginContext lc = new LoginContext(NodeConstants.LOGIN_CONTEXT_DATA_ADMIN, subject);
  			lc.login();
  		} catch (LoginException e) {
  			throw new CmsException("Cannot login as system", e);
  		} finally {
  			Thread.currentThread().setContextClassLoader(origClassLoader);
  		}
  		if (log.isTraceEnabled())
  			log.trace("System authenticated");
  	}
  
  	protected void deauthenticateAsSystem() {
  		ClassLoader origClassLoader = Thread.currentThread().getContextClassLoader();
  		Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
  		try {
  			LoginContext lc = new LoginContext(NodeConstants.LOGIN_CONTEXT_DATA_ADMIN, subject);
  			lc.logout();
  		} catch (LoginException e) {
  			throw new CmsException("Cannot logout as system", e);
  		} finally {
  			Thread.currentThread().setContextClassLoader(origClassLoader);
  		}
  	}
  
  	protected Subject getSubject() {
  		return subject;
  	}
  }