package com.aragost.javahg;
   
   import com.aragost.javahg.internals.AbstractCommand;
   
   /**
    * Exception thrown when an attempt it made to execute a command that
    * the underlying Mercurial command server doesn't know.
    * <p>
    * Since Mercurial from time to time introduce new commands (e.g.
   * phase, graft), JavaHg implements these. But if you attempt to use
   * them against an older version of Mercurial you get this exception.
   * 
   */
  public class UnknownCommandException extends RuntimeException {
  
      private static final long serialVersionUID = 1L;
  
      // TODO Exceptions are Serializable, AbstractCommand not. So we
      // should not have it as a non-transient field.
      private final AbstractCommand command;
  
      public UnknownCommandException(AbstractCommand cmd) {
          super(createMessage(cmd));
          this.command = cmd;
      }
  
      private static String createMessage(AbstractCommand cmd) {
          HgVersion hgVersion = getHgVersion(cmd);
          return "Mercurial command '" + cmd.getCommandName() + "' is not supported by Mercurial version: "
                  + hgVersion.getVersionString();
      }
  
      private static HgVersion getHgVersion(AbstractCommand cmd) {
          HgVersion hgVersion = HgVersion.unknown();
          try {
              hgVersion = cmd.getRepository().getHgVersion();
          } catch (RuntimeException e) {
              // Something went wrong, but ignore this so we can create
              // this exception
          }
          return hgVersion;
      }
  
      public AbstractCommand getCommand() {
          return command;
      }
  
  }