Java设计模式 - 命令模式
命令模式是数据驱动设计模式它是行为模式之一。
请求被作为命令的对象包装传递给invoker对象。
Invoker对象将命令传递到相应的对象并且该对象执行该命令。
例子
import java.util.ArrayList;
import java.util.List;
interface Command {
void execute();
}
class MouseCursor {
private int x = 10;
private int y = 10;
public void move() {
System.out.println("Old Position:"+x +":"+y);
x++;
y++;
System.out.println("New Position:"+x +":"+y);
}
public void reset() {
System.out.println("reset");
x = 10;
y = 10;
}
}
class MoveCursor implements Command {
private MouseCursor abcStock;
public MoveCursor(MouseCursor abcStock) {
this.abcStock = abcStock;
}
public void execute() {
abcStock.move();
}
}
class ResetCursor implements Command {
private MouseCursor abcStock;
public ResetCursor(MouseCursor abcStock) {
this.abcStock = abcStock;
}
public void execute() {
abcStock.reset();
}
}
class MouseCommands {
private List<Command> orderList = new ArrayList<Command>();
public void takeOrder(Command order) {
orderList.add(order);
}
public void placeOrders() {
for (Command order : orderList) {
order.execute();
}
orderList.clear();
}
}
public class Main {
public static void main(String[] args) {
MouseCursor cursor = new MouseCursor();
MoveCursor moveCursor = new MoveCursor(cursor);
ResetCursor resetCursor = new ResetCursor(cursor);
MouseCommands commands= new MouseCommands();
commands.takeOrder(moveCursor);
commands.takeOrder(resetCursor);
commands.placeOrders();
}
}
以上代码生成结果为：
Old Position:10:10
New Position:11:11
reset