Command设计模式

Receiver类

do(){}

undo(){}

ConcreteCommand类

构造函数

public ConcreteCommand(Receiver rec){

this.rec = rec;

}

public bool do(){

return rec.do();

}

public bool undo(){

return rec.undo();

}

Invoker类

undolist;

redolist;

public void doCommand(Command command){

if(command.do()){

undolist.add(command);

}

}

public void undo(){

for(Command command : undolist){

if(command.undo()){

undolist.remove(command);

redolist.add(command);

}

}

}

Client类

main{

Invoker invoker = new Invoker();

Receiver receiver = new Receiver();

Command command = new ConcreteCommand(receiver);

invoker.doCommand(command);

//

invoker.undo();

}