package org.codehaus.plexus.util.cli;
   
   /*
    * Copyright The Codehaus 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.
   */
  
  import java.util.StringTokenizer;
  
  /**
   * The java.util.StringTokenizer is horribly broken. Given the string 1,,,3,,4 (, delim) It will return 1,3,4 Which is
   * clearly wrong - 1,EMPTY,EMPTY,3,EMPTY,4 is what it should return
   * 
   *
   */
  public final class EnhancedStringTokenizer
  {
      private StringTokenizer cst = null;
  
      String cdelim;
  
      final boolean cdelimSingleChar;
  
      final char cdelimChar;
  
      boolean creturnDelims;
  
      String lastToken = null;
  
      boolean delimLast = true;
  
      public EnhancedStringTokenizer( String str )
      {
          this( str, " \t\n\r\f", false );
      }
  
      public EnhancedStringTokenizer( String str, String delim )
      {
          this( str, delim, false );
      }
  
      public EnhancedStringTokenizer( String str, String delim, boolean returnDelims )
      {
          cst = new StringTokenizer( str, delim, true );
          cdelim = delim;
          creturnDelims = returnDelims;
          cdelimSingleChar = ( delim.length() == 1 );
          cdelimChar = delim.charAt( 0 );
      }
  
      public boolean hasMoreTokens()
      {
          return cst.hasMoreTokens();
      }
  
      private String internalNextToken()
      {
          if ( lastToken != null )
          {
              String last = lastToken;
              lastToken = null;
              return last;
          }
  
          String token = cst.nextToken();
          if ( isDelim( token ) )
          {
              if ( delimLast )
              {
                  lastToken = token;
                  return "";
              }
              else
              {
                  delimLast = true;
                  return token;
              }
          }
          else
          {
              delimLast = false;
              return token;
          }
      }
  
      public String nextToken()
      {
          String token = internalNextToken();
         if ( creturnDelims )
         {
             return token;
         }
         if ( isDelim( token ) )
         {
             return hasMoreTokens() ? internalNextToken() : "";
         }
         else
         {
             return token;
         }
     }
 
     private boolean isDelim( String str )
     {
         if ( str.length() == 1 )
         {
             char ch = str.charAt( 0 );
             if ( cdelimSingleChar )
             {
                 if ( cdelimChar == ch )
                 {
                     return true;
                 }
             }
             else
             {
                 if ( cdelim.indexOf( ch ) >= 0 )
                 {
                     return true;
                 }
             }
         }
         return false;
 
     }
 }