大熊君说说JS与设计模式之------策略模式Strategy

var dataSourceVendor = {
xml : {
get : function(){
console.log("XML数据源") ;
}
} ,
json : {
get : function(){
console.log("JSON数据源") ;
}
} ,
csv : {
get : function(){
console.log("CSV数据源") ;
}
}
} ;
console.log("选择的数据源：" + dataSourceVendor["json"]["get"]()) ;

var validator = { types:{}, messages:[], config:{}, validate:function (data) {
var i, msg, type, checker, result_ok;
this.messages = [];
for (i in data) {
if (data.hasOwnProperty(i)) {
type = this.config[i];
checker = this.types[type];
if (!type) {
continue;
}
if (!checker) {
throw {
name:"ValidationError",
message:"No handler to validate type " + type
};
}
result_ok = checker.validate(data[i]);
if (!result_ok) {
msg = "Invalid value for *" + i + "*, " + checker.instructions;
this.messages.push(msg);
}
}
}
return this.hasErrors();
},
hasErrors:function () {
return this.messages.length !== 0;
}
}; validator.types.isNonEmpty = {
validate:function (value) {
return value !== "";
},
instructions:"the value cannot be empty"
}; validator.types.isNumber = {
validate:function (value) {
return !isNaN(value);
},
instructions:"the value can only be a valid number, e.g. 1, 3.14 or 2010"
}; validator.types.isAlphaNum = {
validate:function (value) {
return !/[^a-z0-9]/i.test(value);
},
instructions:"the value can only contain characters and numbers, no special symbols"
}; var data = {
first_name:"Super",
last_name:"Man",
age:"unknown",
username:"o_O"
};
validator.config = {
first_name:'isNonEmpty',
age:'isNumber',
username:'isAlphaNum'
};
validator.validate(data);
if (validator.hasErrors()) {
console.log(validator.messages.join("\n"));
}