【发布时间】：2013-10-01 18:48:16
【问题描述】：
我正在使用 JavaScript 处理命名空间、类、继承和模式责任链，但它不起作用 - 我尝试遵循 this tutorial，但是当我尝试实现命名空间和超级构造函数时，它不起作用，所以我想我错过了一些东西。
我将类放在不同的文件中，并且使用相同的命名空间。我有课，Constraint.js:
var Namespace = Namespace || {};
//parent class
Namespace.Constraint = (function() {
//How can I do a constructor with the namespace?
/**
function Namespace.Constraint(value, succesor, type) {
this.value = value;
this.succesor = succesor;
this.type = type;
this.noTopic = "UNDEFINED";
}
*/
Namespace.Constraint.prototype.handle = function() {
if (this.has()) {
return this.succesor.handle();
}
}
Namespace.Constraint.prototype.has = function() {
return this.type != this.noTopic;
}
return Constraint;
})();
接下来是有继承的类，在另一个文件StringConstraint.js：
var Namespace = Namespace ||{};
Namespace.StringConstraint = (function(_super){
/**Constructor child*/
/*
Namespace.StringConstraint = function(value, succesor) {
_super.call(value, succesor, "string");
How to call the constructor of the parent?
}
*/
Namespace.StringConstraint.prototype.handle = function() {
if (this.has()) {
return "type=text";
}
else{
/* Is this the correct way to call a method of the parent? */
_super.prototype.handle.call(this);
}
}
Namespace.StringConstraint.prototype.has=function(){
/* this.type is a value of parent class. Is this the correct way
to call it? Maybe I should use _super.type?
*/
return this.type === "string";
}
return Namespace.StringConstraint;
})(Namespace.Constraint); //Reference to parent, but is it fine with the namespace?
还有班级BuilderConstraint.js：
var Namespace = Namespace ||{};
Namespace.BuilderConstraint = (function() {
this.constraints = new Array();
Namespace.BuilderConstraint.prototype.add = function( constraint ) {
this.constraints.push(constraint);
}
Namespace.BuilderConstraint.prototype.applyConstraint = function(callback) {
for (constraint in this.constraints) {
//How to ensure that class is Constraint?
//Because I could get object [index], has not a method handle.
callback(constraint.handle());
}
}
})();
最后是 app.js 文件，这是我的 Main：
$(function() {
var value = "string";
var builderConstraint = new Namespace.BuilderConstaint();
var stringConstraint = new Namespace.StringConstraint(value,null);
builderConstraint.add(stringConstraint);
builderConstraint.applyConstraint(function(out) {
console.log(out);
})
});
我希望不要很尴尬，但我很困惑。
所以，我的问题是：
- 如何在不同的 JavaScript 文件中正确使用命名空间？
- 如何在不覆盖命名空间的情况下添加类？
- 如何使用命名空间编写类的构造函数？
- 如何在 子类的构造函数？
- 在命名空间中使用继承类的正确方法是什么？
- 如何在子类中正确使用 parents 属性？
这是一个类约束（父类）：
/**
* Clase padre
*/
var XMLFormBuilder = XMLFormBuilder || {};
XMLFormBuilder.Constraint= (function()
{
function Constraint( value, succesor, type ) {
this.value = value || "UNDEFINED";
this.succesor = succesor || null;
this.type = type || "UNDEFINED";
this.noTopic = "UNDEFINED";
};
Constraint.prototype.handle = function()
{
if (typeof null != this.succesor ) {
{
return this.succesor.handle();
}
};
Constraint.prototype.has = function()
{
return this.type != this.noTopic;
};
return Constraint;
})(); // <-- **Here, there is a trouble.**
班级StringConstraint（儿童班）：
/**Child class*/
var XMLFormBuilder = XMLFormBuilder || {};
XMLFormBuilder.StringConstraint=(function(_super)
{
function StringConstraint(value, succesor)
{
this.value = value || "UNDEFINED";
this.succesor = succesor || null;
_super.call( this.value, this.succesor, "cadena" );
/**
* How to I do to use the constructor of class parent in the constructor of class child?
* Aquí hay un error, porque no se como llamar correctamente al contructor
* de la clase padre o como lo sugiere el error que _super no esta definido.
* Cannot call method 'call' of undefined;
*/
};
/* Aquí se genera un error si activo la sobreescritura del prototipo:
Uncaught SyntaxError: Unexpected token ) /entidad/js/Constraint.js:28
Uncaught TypeError: undefined is not a function StringConstraint.js:16
Uncaught TypeError: undefined is not a function
There is a trouble, because I can't overwrite the prototype
*/
//StringConstraint.prototype = new _super;
StringConstraint.prototype.handle=function()
{
if(this.has())
return "type='text'";
else
return _super.handle();
};
StringConstraint.prototype.has = function()
{
return this.type === "cadena";
}
return StringConstraint;
})(XMLFormBuilder.Constraint);
这是一个班级BuilderConstraint：
var XMLFormBuilder = XMLFormBuilder || {};
XMLFormBuilder.BuilderConstraint = (function()
{
function BuilderConstraint() {
this.constraints = new Array();
}
BuilderConstraint.prototype.add = function(constraint){
this.constraints.push(constraint);
}
BuilderConstraint.prototype.applyContraints = function()
{
var out = "";
/*
this.constraints.forEach(function(object){
out += object.handle();
});
*/
for (var index in this.constraints) {
var constraint = this.constraints[index];
/* Aquí se me presenta un error, ya que no me
* reconoce el método handle de los objetos tipo Constraint
* que agrege al array
*/
out+= constraint.handle();
}
return out;
}
return BuilderConstraint;
})();
这是app.js：
$(function()
{
var value = "cadena";
var stringConstraint = new XMLFormBuilder.StringConstraint(value);
var builderConstraint = new XMLFormBuilder.BuilderConstraint();
builderConstraint.add(stringConstraint);
console.log(builderConstraint.applyContraints());
});
/**
* This is the summary the problems:
* Uncaught SyntaxError: Unexpected token ) Constraint.js:28
* Uncaught TypeError: Cannot call method 'call' of undefined
*/
您可以在此处查看代码：https://gist.github.com/cristianchaparroa/f4ace75aeb8cff04181a
【问题讨论】：
标签： javascript class inheritance namespaces chain-of-responsibility