BTreeExample.java

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package aud.example;
 
import aud.util.*;
 
import aud.BTree;
import aud.KTreeNode;
import java.util.Scanner;
 
public class BTreeExample extends SingleStepper {
 
  class MyTree extends BTree<String> {
    BTreeExample app_ = null;
    public MyTree(int m,BTreeExample app) { super(m); }
 
    @Override protected void onSplit(KTreeNode<String> node) {
      // TODO decorate node
      halt("insert requires split...");
      super.onSplit(node);
    }
  }
 
  protected MyTree tree_ = null;
  protected DotViewer viewer_ = DotViewer.displayWindow
    ((String) null,"aud.example.BTreeExample");
 
  public BTreeExample(int m) {
    super("aud.example.BTreeExample");
    tree_=new MyTree(m,this);
  }
 
  public MyTree getTree() { return tree_; }
 
  @Override protected void onHalt() {
    if (tree_!=null)
      viewer_.display(tree_);
  }
 
  public static void main(String[] args) {
 
    final String HELP=
      "usage: java aud.example.BTreeExample [M] [pause]\n"+
      "       Reads and insert words from standard input.\n"+
      "       'quit' quits.\n"+
      "\tpause [milliseconds] set pause between animation steps\n"+
      "\t      A value of 0 requires to explicitly push the 'continue'\n"+
      "\t      button. The default value is 0 (or the value of then\n"+
      "\t      environment variable 'AUD_TIMEOUT')!\n";
 
    int m=args.length>0 ? Integer.parseInt(args[0]) : 1;
 
    BTreeExample app=new BTreeExample(m);
 
    if (args.length>1) {
      try {
        app.setTimeout(Integer.parseInt(args[1]));
      } catch (NumberFormatException e) {
        System.err.println(HELP);
        System.exit(-1);
      }
    }
 
    app.halt("EMPTY TREE");
 
    Scanner s=new Scanner(System.in);
    s.useDelimiter("\\s+");
 
    while (s.hasNext()) {
      String key=s.next();
      if (key.compareTo("quit")==0)
        break;
      else {
        app.getTree().insert(key);
        app.halt("inserted '"+key);
      }
    }
    app.halt("QUIT");
    System.exit(0);
  }
}