package plp.sort;

import java.util.*;

public class SortableDataTracer extends Observable implements SortableData {

    public static final String SWAP_NAME = "Swap";
    public static final String COMPARE_NAME = "Compare";
    public static final String ACCESS_NAME = "Access";

    public class Operation {
	private String name;
	private int [] indices;

	private Operation(String name, int [] indices) {
	    this.name = name;
	    this.indices = indices;
	}

	public String name() {
	    return name;
	}

	public int [] indices() {
	    return indices;
	}
    }

    private SortableData data;

    public SortableDataTracer(SortableData data) {
	this.data = data;
    }

    public int length() {
	return data.length();
    }

    private void notify(String name, int [] t) {
	setChanged();
	notifyObservers(new Operation(name, t));
    }

    public void swap(int i, int j) {
	data.swap(i, j);
	int [] t = {i, j};
	notify(SWAP_NAME, t);
    }

    public Object access(int i) {
	Object o = data.access(i);
	int [] t = {i};
	notify(ACCESS_NAME, t);
	return o;
    }

    public int compare(int i, int j) {
	int comp = data.compare(i, j);
	int [] t = {i, j};
	notify(COMPARE_NAME, t);
	return comp;
    }
}