stringutilities.java

一个用java写的mail.里面的代码值得我们去研究！学习。

/*
** $Id: StringUtilities.java,v 1.3 2001/05/07 12:34:45 kunugi Exp $
**
** Copyright (c) 2000-2001 Jeff Gay
** on behalf of ICEMail.org <http://www.icemail.org>
** Copyright (c) 1998-2000 by Timothy Gerard Endres
** 
** This program is free software.
** 
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE.
*/

package org.icemail.util;

import java.util.Hashtable;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.Vector;


public class StringUtilities
{
  static public String[]
  vectorToStringArray( Vector sV ) {
    int       sz = sV.size();
    String[]  result = new String[ sz ];

    for ( int i = 0 ; i < sz ; ++i ) {
      result[i] = (String) sV.elementAt(i);
    }

    return result;
  }

  /**
   * Split a string into a string array containing the substrings
   * between the delimiters.
   *
   * NOTE This method WILL <strong>NOT</strong> return an empty
   * token at the end of the array that is returned, if the string
   * ends with the delimiter. If you wish to have a property string
   * array that ends with the delimiter return an empty string at
   * the end of the array, use <code>vectorString()</code>.
   */
  static public String[]
  splitString( String splitStr, String delim ) {
    int             i;
    int             count;
    String[]        result;
    StringTokenizer toker;

    toker = new StringTokenizer( splitStr, delim );

    count = toker.countTokens();

    result = new String[ count ];

    for ( i = 0 ; i < count ; ++i ) {
      try {
        result[i] = toker.nextToken();
      } catch ( NoSuchElementException ex ) {
        result = null;
        break;
      }
    }
    return result;
  }

  /**
   * Split a string into a string Vector containing the substrings
   * between the delimiters.
   *
   * NOTE This method WILL return an empty
   * token at the end of the array that is returned, if the string
   * ends with the delimiter.
   */
  static public Vector
  vectorString( String splitStr, String delim ) {
    boolean         tokeWasDelim = false;
    int             i;
    int             count;
    StringTokenizer toker;

    Vector          result = new Vector();

    toker = new StringTokenizer( splitStr, delim, true );
    count = toker.countTokens();

    for ( i = 0 ; i < count ; ++i ) {
      String toke;

      try {
        toke = toker.nextToken();
      } catch ( NoSuchElementException ex ) {
        break;
      }

      if ( toke.equals( delim ) ) {
        if ( tokeWasDelim )
          result.addElement( "" );
        tokeWasDelim = true;
      } else {
        result.addElement( toke );
        tokeWasDelim = false;
      }
    }

    if ( tokeWasDelim )
      result.addElement( "" );

    return result;
  }

  public static String
  join( String[] strings, String sep ) {
    StringBuffer result = new StringBuffer();

    for ( int i = 0 ; strings != null && i < strings.length ; ++i ) {
      if ( i > 0 )
        result.append( sep );
      result.append( strings[i] );
    }

    return result.toString();
  }

  public static String[]
  argumentSubstitution( String[] args, Hashtable vars ) {
    StringBuffer argBuf = new StringBuffer();

    String[] result = new String[ args.length ];

    for ( int aIdx = 0 ; aIdx < args.length ; ++aIdx ) {
      String argStr = args[ aIdx ];

      int index = argStr.indexOf( '$' );

      if ( index < 0 ) {
        result[ aIdx ] = argStr;
        continue;
      } else {
        result[ aIdx ] = StringUtilities.stringSubstitution( argStr, vars );
      }
    }
    return result;
  }

  public static String
  stringSubstitution( String argStr, Hashtable vars ) {
    StringBuffer argBuf = new StringBuffer();

    for ( int cIdx = 0 ; cIdx < argStr.length() ; ) {
      char ch = argStr.charAt( cIdx );

      switch ( ch ) {
      case '$':
        StringBuffer nameBuf = new StringBuffer();
        for ( ++cIdx ; cIdx < argStr.length() ; ++cIdx ) {
          ch = argStr.charAt( cIdx );
          if ( ch == '_' || Character.isLetterOrDigit( ch ) )
            nameBuf.append( ch );
          else
            break;
        }

        if ( nameBuf.length() > 0 ) {
          String value = (String)vars.get( nameBuf.toString() );

          if ( value != null ) {
            argBuf.append( value );
          }
        }
        break;
        
      default:
        argBuf.append( ch );
        ++cIdx;
        break;
      }
    }

    return argBuf.toString();
  }

  public static String[]
  parseArgumentString( String argStr ) {
    String[] result = null;

    Vector vector = StringUtilities.parseArgumentVector( argStr );

    if ( vector != null && vector.size() > 0 ) {
      result = new String[ vector.size() ];
      vector.copyInto( result );
    }
    return result;
  }

  public static Vector
  parseArgumentVector( String argStr ) {
    Vector      result = new Vector();
    StringBuffer  argBuf = new StringBuffer();

    boolean backSlash = false;
    boolean matchSglQuote = false;
    boolean matchDblQuote = false;

    for ( int cIdx = 0 ; cIdx < argStr.length() ; ++cIdx ) {
      char ch = argStr.charAt( cIdx );

      switch ( ch ) {
        //
        // W H I T E S P A C E
        //
      case ' ':
      case '\t':
      case '\n':
      case '\r':
        if ( backSlash ) {
          argBuf.append( ch );
          backSlash = false; 
        } else if ( matchSglQuote || matchDblQuote ) {
          argBuf.append( ch );
        } else if ( argBuf.length() > 0 ) {
          result.addElement( argBuf.toString() );
          argBuf.setLength( 0 );
        }
        break;

      case '\\':
        if ( backSlash ) {
          argBuf.append( "\\" );
          }
        backSlash = ! backSlash;
        break;

      case '\'':
        if ( backSlash ) {
          argBuf.append( "'" );
          backSlash = false; 
        } else if ( matchSglQuote ) {
          result.addElement( argBuf.toString() );
          argBuf.setLength( 0 );
          matchSglQuote = false;
        } else if ( ! matchDblQuote ) {
          matchSglQuote = true;
        }
        break;

      case '"':
        if ( backSlash ) {
          argBuf.append( "\"" );
          backSlash = false; 
        } else if ( matchDblQuote ) {
          result.addElement( argBuf.toString() );
          argBuf.setLength( 0 );
          matchDblQuote = false;
        } else if ( ! matchSglQuote ) {
          matchDblQuote = true;
        }
        break;

      default:
        if ( backSlash ) {
          switch ( ch ) {
          case 'b': argBuf.append( '\b' ); break;
          case 'f': argBuf.append( '\f' ); break;
          case 'n': argBuf.append( '\n' ); break;
          case 'r': argBuf.append( '\r' ); break;
          case 't': argBuf.append( '\t' ); break;

          default:
            char ch2 = argStr.charAt( cIdx+1 );
            char ch3 = argStr.charAt( cIdx+2 );
            if ( (ch  >= '0' && ch  <= '7') &&
                 (ch2 >= '0' && ch2 <= '7') &&
                 (ch3 >= '0' && ch3 <= '7') ) {
              int octal = ( ( (ch - '0') * 64 ) + ( (ch2 - '0') * 8 ) + (ch3 - '0') );
              argBuf.append( (char) octal );
              cIdx += 2;
            } else if ( ch == '0' ) {
              argBuf.append( '\0' );
            } else {
              argBuf.append( ch );
            }
            break;
          }
        } else {
          argBuf.append( ch );
        }

        backSlash = false;
        break;
      }
    }

    if ( argBuf.length() > 0 ) {
      result.addElement( argBuf.toString() );
    }

    return result;
  }
  
}