Bombarding the national territory, whether with tube artillery or rockets, is an act of war. Has been since the invention of gunpowder. When Hamas wants a cease fire, all they have to do is stop launching rockets into Israel. Since Hamas is still launching, obviously they want the shooting to continue. They figure they get favorable press treatment and generate sympathy in Europe and the UN. And in fact, the world and the US press has been falling over themselves to give Hamas good copy. Even Fox. Lots of video of bombs exploding in Gaza, ambulances hauling off Palestinian wounded, wounded children in Gaza hospital beds. No video of Israeli buildings struck by rockets, firemen battling blazes in Tel Aviv, Jewish families mourning their dead.
As far as the Israeli's are concerned, long as the rockets are flying, they plan to keep hurting Hamas, by which they mean everyone in Gaza. Hamas only exists because everyone in Gaza supports them. Actually, the Israeli's have been quite restrained. If the Israelis really wanted to kill Palestinians, a quick carpet bombing of a few Gaza apartment complexes would kill thousands. Gaza is wall-to-wall people, they could hardly miss.
Trouble with the Israeli strategy. Their enemy is crazy. Hamas wants to exterminate the Jews, no amount of talking to 'em is gonna change their minds about that. Their schools teach hatred of Jews to their children. Their mosques teach the same. They think of themselves as martyrs, they want to be killed in action against Israel. You cannot punish people like that enough to cow them or change their minds. I figure Israel would have to kill off 50% of 'em to have much effect. And the Israelis are too civilized to engage in that kind of genocide. Israel can make 'em smart some, but their scruples don't allow the outrageous amount of killing needed to have any real effect on Hamas.