/*
    * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/cookie/CookiePolicy.java,v 1.7.2.2 2004/02/22 18:21:15 olegk Exp $
    * $Revision: 1.7.2.2 $
    * $Date: 2004/02/22 18:21:15 $
    *
    * ====================================================================
    *
    *  Copyright 2002-2004 The Apache Software Foundation
    *
   *  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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */
  
  package org.apache.commons.httpclient.cookie;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /***
   * Cookie management policy class. The cookie policy provides corresponding
   * cookie management interfrace for a given type or version of cookie. 
   * <p>RFC 2109 specification is used per default. Other supported specification
   * can be  chosen when appropriate or set default when desired
   * <p>The following specifications are provided:
   *  <ul>
   *   <li><tt>COMPATIBILITY</tt>: compatible with the common cookie management
   *   practices *  (even if they are not 100% standards compliant)
   *   <li><tt>NETSCAPE_DRAFT</tt>: Netscape cookie draft compliant
   *   <li><tt>RFC2109</tt>: RFC2109 compliant (default)
   *  </ul>
   * <p>Default policy can be set on JVM start-up through the system property 
   *  <tt>"apache.commons.httpclient.cookiespec"</tt>. Recognized values: 
   *  <tt>COMPATIBILITY</tt>, <tt>NETSCAPE_DRAFT</tt>, <tt>RFC2109</tt>.
   * 
   * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
   * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
   *
   * @since 2.0
   */
  public abstract class CookiePolicy {
  
      /*** cookiespec system property. */
      private static final String SYSTEM_PROPERTY =
          "apache.commons.httpclient.cookiespec";
  
      /***
       * The <tt>COMPATIBILITY</tt> policy provides high compatibilty 
       * with common cookie management of popular HTTP agents.
       */
      public static final int COMPATIBILITY = 0;
  
      /*** The <tt>NETSCAPE_DRAFT</tt> Netscape draft compliant policy. */
      public static final int NETSCAPE_DRAFT = 1;
  
      /*** The <tt>RFC2109</tt> RFC 2109 compliant policy. */
      public static final int RFC2109 = 2;
  
      /*** The default cookie policy. */
      private static int defaultPolicy = RFC2109;
  
      /*** Log object. */
      protected static final Log LOG = LogFactory.getLog(CookiePolicy.class);
  
      static {
          String s = null;
          try {
              s = System.getProperty(SYSTEM_PROPERTY);
          } catch (SecurityException e) {
          }
          if ("COMPATIBILITY".equalsIgnoreCase(s)) {
              setDefaultPolicy(COMPATIBILITY);
          } else if ("NETSCAPE_DRAFT".equalsIgnoreCase(s)) {
              setDefaultPolicy(NETSCAPE_DRAFT);
          } else if ("RFC2109".equalsIgnoreCase(s)) {
              setDefaultPolicy(RFC2109);
          } else {
              if (s != null) {
                  LOG.warn("Unrecognized cookiespec property '" + s
                      + "' - using default");
              }
              setDefaultPolicy(defaultPolicy);
         }
     }
 
     /***
      * @return default cookie policy
      *  <tt>(COMPATIBILITY | NETSCAPE_DRAFT | RFC2109)</tt>
      */
     public static int getDefaultPolicy() {
         return defaultPolicy;
     }
     
 
     /***
      * @param policy new default cookie policy
      *  <tt>(COMPATIBILITY | NETSCAPE_DRAFT | RFC2109)</tt>
      */
     public static void setDefaultPolicy(int policy) {
         defaultPolicy = policy;
     }
     
 
     /***
      * @param policy cookie policy to get the CookieSpec for
      * @return cookie specification interface for the given policy
      *  <tt>(COMPATIBILITY | NETSCAPE_DRAFT | RFC2109)</tt>
      */
     public static CookieSpec getSpecByPolicy(int policy) {
         switch(policy) {
             case COMPATIBILITY: 
                 return new CookieSpecBase(); 
             case NETSCAPE_DRAFT: 
                 return new NetscapeDraftSpec(); 
             case RFC2109:
                 return new RFC2109Spec();
             default:
                 return getSpecByPolicy(defaultPolicy); 
         }
     }
 
 
     /***
      * @return default cookie specification interface
      */
     public static CookieSpec getDefaultSpec() {
         return getSpecByPolicy(defaultPolicy);
     }
     
 
     /***
      * Gets the CookieSpec for a particular cookie version.
      * 
      * <p>Supported versions:
      * <ul>
      *  <li><tt>version 0</tt> corresponds to the NETSCAPE_DRAFT
      *  <li><tt>version 1</tt> corresponds to the RFC2109
      *  <li>Any other cookie value coresponds to the default spec
      * <ul>
      *
      * @param ver the cookie version to get the spec for
      * @return cookie specification interface intended for processing 
      *  cookies with the given version 
      */
     public static CookieSpec getSpecByVersion(int ver) {
         switch(ver) {
             case 0: 
                 return new NetscapeDraftSpec(); 
             case 1:
                 return new RFC2109Spec();
             default:
                 return getDefaultSpec(); 
         }
     }
 
     /***
      * @return cookie specification interface that provides high compatibilty 
      * with common cookie management of popular HTTP agents
      */
     public static CookieSpec getCompatibilitySpec() {
         return getSpecByPolicy(COMPATIBILITY);
     }
 }