@Override
	public void supprimerAvant() {
		if(this.selection.getLongueur() > 0) {
			this.buffer.effacer(this.selection.getDebut(), this.selection.getFin());
			this.selection.setFin(this.selection.getDebut());
		} else if(this.buffer.size() >= this.selection.getDebut()) {
			this.buffer.effacer(this.selection.getDebut(),this.selection.getDebut()+1);
		}
		this.setChanged();
		this.notifyObservers(this.buffer.getContenu());
		this.setChanged();
		this.notifyObservers(this.selection.getDebut());
	}