PHP State Mode Learning Notes

If, according to General thinking, every time we operate on a pawn, such as a tank, we have to use if to judge his state, so there will be a lot of if,else or Swith in the code.

But we can see that what we need is his behavior in a certain state, and if we encapsulate these behaviors in a state, we can reduce a lot of judgment.

The problem to be solved: encapsulate the state of the tank and let the state control its behavior.

Thinking: The state as the attribute, the soldier kind itself only controls the change of state, the concrete behavior is defined by the State class.

Status (State) mode example:

The code is as follows

Copy Code

<?php interface of the tank state Interface Tankstate { The attack method of the tank Public function attack (); } Tank Normal state Class Tankstate_tank implements Tankstate { The attack method of the tank Public Function Attack () { Here the simple output current state echo "Ordinary state"; } } The state of the tank's frame Class Tankstate_siege implements Tankstate { The attack method of the tank Public Function Attack () { Here the simple output current state echo "stands up"; } } Tank class Class Tank { State Public $state; The attack method of the tank Public Function __construct () { The newly built tank is, of course, a normal state. $this->state = new Tankstate_tank (); } Set the state of the method, assuming the parameter for the player to click on the keyboard Public Function SetState ($key) { If you press the S if ($key = ' s ') { $this->state = new Tankstate_siege (); } If you press the T ElseIf ($key = ' t ') { $this->state = new Tankstate_tank (); } } The attack method of the tank Public Function Attack () { Handling attacks by the current state itself $this->state->attack (); } } Build a new tank. $tank = new tank (); Assuming an enemy is passing by, the tank is attacked in normal mode. $tank->attack (); Stand up tanks. $tank->setstate (' s '); Tank attack again, this time it's a model. $tank->attack (); ?>

Usage Summary: State mode can encapsulate the behavior and attributes associated with state, except when switching state, other places do not need a large number of the current state of the decision, as long as the current state of the method call.

Implementation summary: Use an interface specification State class needs to implement the method, such as the above Tankstate specified attack (). Encapsulate each state into a class, putting different methods in different states into their respective state classes, such as the attack method above, and all state execution interfaces. The original transaction class, such as the above tank class, only responsible for state switching, once the need for a method of call, as long as the current state can be