public void filter(String column, String by) {
		if (by.equals("")) {
			this.isFiltered = false;
		} else {
			this.isFiltered = true;
			this.filteredSelectionSet = new ResourceSet();
			switch (column) {
			case "Author":
				for (Resource r : this.exerciseSet) {
					Exercise e = (Exercise) r;
					if (e.getAuthor().contains(by)) {
						this.filteredSelectionSet.add(e);
					}
				}
				break;
			case "Exercise Name":
				for (Resource r : this.exerciseSet) {
					Exercise e = (Exercise) r;
					if (e.getExerciseName().contains(by)) {
						this.filteredSelectionSet.add(e);
					}
				}
				break;
			}
		}
		this.refreshTable();
		this.exerciseTable.refreshData(this.filteredSelectionSet);
		this.exerciseTable.fireTableDataChanged();
	}