/* 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.taglibs.authz;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.context.SecurityContext;

 import org.acegisecurity.context.SecurityContextHolder;

 import org.acegisecurity.userdetails.UserDetails;

 import java.io.IOException;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 import java.util.HashSet;

 import java.util.Set;

 import javax.servlet.jsp.JspException;

 import javax.servlet.jsp.tagext.Tag;

 import javax.servlet.jsp.tagext.TagSupport;

 /**

  * An {@link javax.servlet.jsp.tagext.Tag} implementation that allows convenient access to the current

  * <code>Authentication</code> object.<p>Whilst JSPs can access the <code>SecurityContext</code> directly, this tag

  * avoids handling <code>null</code> conditions. The tag also properly accommodates

  * <code>Authentication.getPrincipal()</code>, which can either be a <code>String</code> or a

  * <code>UserDetails</code>.</p>

  *

  * @author Ben Alex

  * @version $Id: AuthenticationTag.java 1784 2007-02-24 21:00:24Z luke_t $

  */

 public class AuthenticationTag extends TagSupport {

     //~ Static fields/initializers =====================================================================================

     private static final Set methodPrefixValidOptions = new HashSet();

     static {

         methodPrefixValidOptions.add("get");

         methodPrefixValidOptions.add("is");

     }

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

     private String methodPrefix = "get";

     private String operation = "";

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

     public int doStartTag() throws JspException {

         if ((null == operation) || "".equals(operation)) {

             return Tag.SKIP_BODY;

         }

         validateArguments();

         if ((SecurityContextHolder.getContext() == null)

             || !(SecurityContextHolder.getContext() instanceof SecurityContext)

             || (((SecurityContext) SecurityContextHolder.getContext()).getAuthentication() == null)) {

             return Tag.SKIP_BODY;

         }

         Authentication auth = SecurityContextHolder.getContext().getAuthentication();

         if (auth.getPrincipal() == null) {

             return Tag.SKIP_BODY;

         } else if (auth.getPrincipal() instanceof UserDetails) {

             writeMessage(invokeOperation(auth.getPrincipal()));

             return Tag.SKIP_BODY;

         } else {

             writeMessage(auth.getPrincipal().toString());

             return Tag.SKIP_BODY;

         }

     }

     public String getMethodPrefix() {

         return methodPrefix;

     }

     public String getOperation() {

         return operation;

     }

     protected String invokeOperation(Object obj) throws JspException {

         Class clazz = obj.getClass();

         String methodToInvoke = getOperation();

         StringBuffer methodName = new StringBuffer();

         methodName.append(getMethodPrefix());

         methodName.append(methodToInvoke.substring(0, 1).toUpperCase());

         methodName.append(methodToInvoke.substring(1));

         Method method = null;

         try {

             method = clazz.getMethod(methodName.toString(), (Class[]) null);

         } catch (SecurityException se) {

             throw new JspException(se);

         } catch (NoSuchMethodException nsme) {

             throw new JspException(nsme);

         }

         Object retVal = null;

         try {

             retVal = method.invoke(obj, (Object[]) null);

         } catch (IllegalArgumentException iae) {

             throw new JspException(iae);

         } catch (IllegalAccessException iae) {

             throw new JspException(iae);

         } catch (InvocationTargetException ite) {

             throw new JspException(ite);

         }

         if (retVal == null) {

             retVal = "";

         }

         return retVal.toString();

     }

     public void setMethodPrefix(String methodPrefix) {

         this.methodPrefix = methodPrefix;

     }

     public void setOperation(String operation) {

         this.operation = operation;

     }

     protected void validateArguments() throws JspException {

         if ((getMethodPrefix() != null) && !getMethodPrefix().equals("")) {

             if (!methodPrefixValidOptions.contains(getMethodPrefix())) {

                 throw new JspException("Authorization tag : no valid method prefix available");

             }

         } else {

             throw new JspException("Authorization tag : no method prefix available");

         }

     }

     protected void writeMessage(String msg) throws JspException {

         try {

             pageContext.getOut().write(String.valueOf(msg));

         } catch (IOException ioe) {

             throw new JspException(ioe);

         }

     }

 }