public Numeric getData(Item item) {
		if (this == BEGIN) {
			return item.getBegin();
		}
		if (this == COMPLETED) {
			return item.getCompleted();
		}
		if (this == DURATION) {
			return item.getDuration();
		}
		if (this == LOAD) {
			return item.getLoad();
		}
		if (this == WORK) {
			return item.getWork();
		}
		throw new UnsupportedOperationException();
	}