UnimplementedFeature.java

/*
** Module   : UnimplementedFeature.java
** Abstract : helper class to cleanly log runtime usage of code that is unimplemented or partial
**
** Copyright (c) 2014-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- --------------------------------Description----------------------------------
** 001 GES 20141029 Created initial version.
** 002 GES 20141118 Added unsupported() method. Synchronized access to the token set.
** 003 HC  20171024 Added 'experimental' set of methods.
** 004 ECF 20171120 Only log stack trace if FINE (or higher) logging level is enabled. Otherwise,
**                  log only the message text.
** 005 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
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**   terms apply to the works covered under the License.  These additional terms
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*/

package com.goldencode.p2j.util;

import com.goldencode.p2j.util.logging.*;

import java.util.logging.*;
import java.util.*;

/**
 * Helper class to cleanly log runtime usage of code that is unimplemented or partial.
 * Each log entry will contain a description as well as a stack trace identifying the call
 * path that tried to use the unimplemented feature.
 * <p>
 * <b>Usage Guidelines</b>
 * <p>
 * <ul>
 *   <li> {@link #missing} should be used for methods/features which have no substantial
 *        implementation provided.
 *   <li> {@link #partial} should be used for methods/features which have some implementation
 *        but it is not complete.  If possible, place the call to <code>partial</code> inside
 *        code that only executes when the missing portions of the implementation would be
 *        executed.
 *   <li> {@link #todo} should be used for anything that needs further review, investigation
 *        or modification.  If possible, place the call to <code>todo</code> inside code
 *        that only executes when the associated condition presents itself.
 *   <li> {@link #unsupported} should be used for anything feature that exists as a placeholder
 *        but which is not ever planned to be supported.
 *   <li> There are forms of each method that take and return a token.  Use these forms if
 *        the logging should only occur the first time the code is executed. This is useful
 *        for features that get called with frequency such that the log file would get filled
 *        with "noise" from excess logging.
 *   <li> When using tokens, they should generally be unique to the specific calling location
 *        otherwise you will have log entries suppressed from unrelated calls to this class.
 *   <li> When the feature is actually implemented, the logging call to this class would 
 *        naturally be remvoed.  <b>Don't forget to delete any associated token data members
 *        at that time!</b> 
 * </ul>
 * <p>
 * Example of using tokens:
 * <p>
 * <pre>
 * private static Object token = null;
 * 
 * public void someMethod()
 * {
 *    if (someCondition)
 *    {
 *       // the first time this is called, the token is null and the log entry will be made
 *       // but subsequent calls will pass the token returned from the first call and the
 *       // logging will be suppressed
 *       token = UnimplementedFeature.todo("This is a description of the TODO.", token);
 *    }
 * }
 * </pre>
 */
public class UnimplementedFeature
{
   /** Logger */
   private static final CentralLogger logger = CentralLogger.get(UnimplementedFeature.class);
   
   /** Set of all tokens provided to callers. */ 
   private static Set<Object> tokens = new HashSet<>(); 
   
   /**
    * Log the given message along with a given stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is completely missing. The
    * logging is unconditionally done (there is no logging level checked) with the level set
    * to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the missing feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    */
   public static void missing(String msg)
   {
      log(Level.SEVERE, "MISSING", msg);
   }
   
   /**
    * Conditionally log the given message if the caller's provided token is <code>null</code>
    * or if it was not a valid token.  Subsequent calls to this method will silently return
    * without logging if the given token already exists in the set of valid tokens. Any log entry
    * will have the given text along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is completely missing. The
    * logging is unconditionally done (there is no logging level checked) with the level set
    * to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the missing feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    * @param    token
    *           A previously provided token value that uniquely distinguishes the caller
    *           or <code>null</code> if this is the first call.
    *
    * @return   The given token if it is a valid previously provided token.  Otherwise a newly
    *           created token will be associated with the caller and returned.
    */
   public static Object missing(String msg, Object token)
   {
      synchronized (UnimplementedFeature.class)
      {
         if (token == null || !tokens.contains(token))
         {
            token = new Object();
            tokens.add(token);
            missing(msg);
         }
      }
      
      return token;
   }
   
   /**
    * Log the given message along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is only partially implemented.
    * The logging is unconditionally done (there is no logging level checked) with the level
    * set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the partial feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    */
   public static void partial(String msg)
   {
      log(Level.SEVERE, "PARTIAL", msg);
   }
   
   /**
    * Conditionally log the given message if the caller's provided token is <code>null</code>
    * or if it was not a valid token.  Subsequent calls to this method will silently return
    * without logging if the given token already exists in the set of valid tokens. Any log entry
    * will have the given text along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is only partially implemented.
    * The logging is unconditionally done (there is no logging level checked) with the level
    * set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the partial feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    * @param    token
    *           A previously provided token value that uniquely distinguishes the caller
    *           or <code>null</code> if this is the first call.
    *
    * @return   The given token if it is a valid previously provided token.  Otherwise a newly
    *           created token will be associated with the caller and returned.
    */
   public static Object partial(String msg, Object token)
   {
      synchronized (UnimplementedFeature.class)
      {
         if (token == null || !tokens.contains(token))
         {
            token = new Object();
            tokens.add(token);
            partial(msg);
         }
      }
      
      return token;
   }
   
   /**
    * Log the given message along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is at an experimental level.
    * The logging is unconditionally done (there is no logging level checked) with the level
    * set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the experimental feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the experimental feature.
    */
   public static void experimental(String msg)
   {
      log(Level.SEVERE, "EXPERIMENTAL", msg);
   }
   
   /**
    * Conditionally log the given message if the caller's provided token is <code>null</code>
    * or if it was not a valid token.  Subsequent calls to this method will silently return
    * without logging if the given token already exists in the set of valid tokens. Any log entry
    * will have the given text along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is at an experimental level.
    * The logging is unconditionally done (there is no logging level checked) with the level
    * set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the experimental feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the experimental feature.
    * @param    token
    *           A previously provided token value that uniquely distinguishes the caller
    *           or <code>null</code> if this is the first call.
    *
    * @return   The given token if it is a valid previously provided token.  Otherwise a newly
    *           created token will be associated with the caller and returned.
    */
   public static Object experimental(String msg, Object token)
   {
      synchronized (UnimplementedFeature.class)
      {
         if (token == null || !tokens.contains(token))
         {
            token = new Object();
            tokens.add(token);
            experimental(msg);
         }
      }
      
      return token;
   }
   
   /**
    * Log the given message along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support has a TODO remaining. The
    * logging is unconditionally done (there is no logging level checked) with the level set
    * to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the TODO will already be
    * readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    */
   public static void todo(String msg)
   {
      log(Level.SEVERE, "TODO", msg);
   }
   
   /**
    * Conditionally log the given message if the caller's provided token is <code>null</code>
    * or if it was not a valid token.  Subsequent calls to this method will silently return
    * without logging if the given token already exists in the set of valid tokens. Any log entry
    * will have the given text along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support has a TODO remaining. The
    * logging is unconditionally done (there is no logging level checked) with the level set
    * to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the TODO will already be
    * readily apparent.
    *
    * @param    msg
    *           A description of the missing feature.
    * @param    token
    *           A previously provided token value that uniquely distinguishes the caller
    *           or <code>null</code> if this is the first call.
    *
    * @return   The given token if it is a valid previously provided token.  Otherwise a newly
    *           created token will be associated with the caller and returned.
    */
   public static Object todo(String msg, Object token)
   {
      synchronized (UnimplementedFeature.class)
      {
         if (token == null || !tokens.contains(token))
         {
            token = new Object();
            tokens.add(token);
            todo(msg);
         }
      }
      
      return token;
   }
   
   /**
    * Log the given message along with a given stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is never expected to be
    * provided. The logging is unconditionally done (there is no logging level checked) with
    * the level set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the unsupported feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the unsupported feature.
    */
   public static void unsupported(String msg)
   {
      log(Level.SEVERE, "UNSUPPORTED", msg);
   }
   
   /**
    * Conditionally log the given message if the caller's provided token is <code>null</code>
    * or if it was not a valid token.  Subsequent calls to this method will silently return
    * without logging if the given token already exists in the set of valid tokens. Any log entry
    * will have the given text along with the a stack trace and a prefix that indicates that
    * a feature was used at runtime for which the runtime support is never expected to be
    * provided. The logging is unconditionally done (there is no logging level checked) with the
    * level set to <code>SEVERE</code>.
    * <p>
    * Since a call stack will be created and logged, the location of the unsupported feature will
    * already be readily apparent.
    *
    * @param    msg
    *           A description of the unsupported feature.
    * @param    token
    *           A previously provided token value that uniquely distinguishes the caller
    *           or <code>null</code> if this is the first call.
    *
    * @return   The given token if it is a valid previously provided token.  Otherwise a newly
    *           created token will be associated with the caller and returned.
    */
   public static Object unsupported(String msg, Object token)
   {
      synchronized (UnimplementedFeature.class)
      {
         if (token == null || !tokens.contains(token))
         {
            token = new Object();
            tokens.add(token);
            unsupported(msg);
         }
      }
      
      return token;
   }
   
   /**
    * Logging helper method that logs a message at the given level.
    *
    * @param    level
    *           Logging level.
    * @param    code
    *           Describes the type of unimplemented feature.
    * @param    msg
    *           The caller-defined message.
    */
   private static void log(Level level, String code, String msg)
   {
      // the code is passed to logp but not honored, so we add it explicitly to the text
      String txt = String.format("%s: %s", code, msg);
      
      if (logger.isLoggable(Level.FINE))
      {
         // include an exception to log the stack trace if debug-level logging enabled
         logger.logp(level, "UnimplementedFeature", code, txt, new RuntimeException());
         
         return;
      }
      
      // log without a stack trace
      logger.logp(level, "UnimplementedFeature", code, txt);
   }
}