// Assignment 4 - Pipe-and-Filter KWIC Indexing.
// Concurrent Programming, CS 498-598
// Summer 2002
//
// This code is unmaintained and may be obsolete (as well as being incorrect).
// See the answer to assignment 4 for possible updates.

import java.util.StringTokenizer;

class 
KWICIndexEntry {

  final private String words[];
  final private int index_word;


  static KWICIndexEntryGroup
  entries(String description) {

    // Return a group of index entries derived from the given description.
    // Return null if there are no index entries.  The group entries are stored
    // in no particular order.

    final String tokens[] = tokenize(description);
    if (tokens == null)
      return null;

    final KWICIndexEntry rotations[] = new KWICIndexEntry[tokens.length];
    
    for (int i = tokens.length - 1; i >= 0; i-- )
      rotations[i] = new KWICIndexEntry(tokens, i);
    
    return new KWICIndexEntryGroup(rotations);
    }


  private
  KWICIndexEntry(String words[], int index_word) {
 
    assert words != null;
    assert (0 <= index_word) && (index_word < words.length);

    this.words = words;
    this.index_word = index_word;
    }


  boolean 
  less(KWICIndexEntry kie) {

    // Return true iff this entry is less than the given entry.

    return words[index_word].compareTo(kie.words[kie.index_word]) < 0;
    }


  private String
  rotated_output() {

    // Create a star-form KWIC index entry.

    String sep = "";
    StringBuffer str = new StringBuffer();

    for (int i = 0; i < words.length; i++) {
      final int j = (index_word + i) % words.length;
      if (j == 0 && i != 0) sep = sep + "* ";
      str.append(sep).append(words[j]);
      sep = " ";
      }

    return str.toString();
    }


  private static String []
  tokenize(String str) {

    // Return the list of tokens in the given input string.  Return null if
    // there are no tokens.

    final StringTokenizer tokenizer = new StringTokenizer(str);

    final int tkn_cnt = tokenizer.countTokens();
    if (tkn_cnt < 1) 
      return null;
    
    final String tokens[] = new String[tkn_cnt];

    for (int i = 0; i < tkn_cnt; i++)
      tokens[i] = tokenizer.nextToken();
    
    return tokens;
    }


  public String
  toString() {
    return rotated_output();
    }


  private String
  unrotated_output() {

    // Create a capital-form KWIC index entry.

    String sep = "";
    StringBuffer str = new StringBuffer();

    for (int i = 0; i < words.length; i++) {
      str.append(sep).append(i == index_word ? words[i].toUpperCase() : words[i]);
      sep = " ";
      }

    return str.toString();
    }
  }