// 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.Vector;

class 
SortFilter
extends FilterRunnableTemplate {

  private Vector descriptions;

  private void
  add(KWICIndexEntryGroup entries) {

    // Put the new entries into the database using insertion sort.

    for (int i = entries.count() - 1; i >= 0; i--) {
      descriptions.add(null);
      final KWICIndexEntry e1 = entries.get(i);
      int j = descriptions.size() - 1;
      while (j > 0) {
	final KWICIndexEntry e2 = (KWICIndexEntry) descriptions.get(j - 1);
	if (e2.less(e1)) 
	  break;
	descriptions.setElementAt(e2, j);
	j--;
	}
      descriptions.setElementAt(e1, j);
      }
    }


  protected void
  end_loop() {

    // On termination the output filter should send the sorted KWIC index entry
    // database downstream.

    try { 
      outb.put(new KWICIndexEntryGroup(descriptions));
      outb.put(null);
      }
    catch (Exception ie) { 
      throw new RuntimeException();
      }
    }


  protected boolean
  isMisbehavingObject(Object o) {
    KWICIndexEntryGroup kie = (KWICIndexEntryGroup) o;
    return 
      (kie.count() == 1) && (kie.get(0).toString().compareTo("sort") == 0);
    }


  protected boolean
  isValidObject(Object o) {

    // The sort filter expects to receive KWIC index entry groups from the
    // upstream (rotate) filter.

    return o instanceof KWICIndexEntryGroup;
    }


  protected void
  misbehave() {
    throw new RuntimeException();
    }


  protected void
  process_input(Object o) {

    // Add each new group of KWIC index entries to the group.

    add((KWICIndexEntryGroup) o);
    }


  SortFilter(String fn, buffer ib, buffer ob) {
    super(fn, ib, ob);
    descriptions = new Vector();
    }
  }