tailieunhanh - php objects patterns and practice 3rd edition phần 3

Để làm được điều đó, bạn nên sử dụng các nhà điều hành instanceof. Hoặc, bạn có thể sử dụng một chức năng mà là một phần của SPL (Standard PHP Library); class_implements () chấp nhận một tên lớp hoặc tham chiếu một đối tượng, và trả về một mảng các tên giao diện | CHAPTER 5 OBJECT TOOLS is_subclass_of will tell you only about class inheritance relationships. It will not tell you that a class implements an interface. For that you should use the instanceof operator. Or you can use a function which is part of the SPL Standard PHP Library . class_implements accepts a class name or an object reference and returns an array of interface names. if in_array someInterface class_implements product print CdProduct is an interface of someInterface n Method Invocation You have already encountered an example in which I used a string to invoke a method dynamically product getProduct acquire an object method getTitle define a method name print product- method invoke the method PHP also provides the call_user_func method to achieve the same end. call_user_func can invoke either methods or functions. To invoke a function it requires a single string as its first argument returnVal call_user_func myFunction To invoke a method it requires an array. The first element of this should be an object and the second should be the name of the method to invoke returnVal call_user_func array myObj methodName You can pass any arguments that the target method or function requires in additional arguments to call_user_func like this product getProduct acquire an object call_user_func array product setDiscount 20 This dynamic call is of course equivalent to product- setDiscount 20 Because you can equally use a string directly in place of the method name like this method setDiscount product- method 20 the call_user_func method won t change your life greatly. Much more impressive though is the related call_user_func_array function. This operates in the same way as call_user_func as far as selecting the target method or function is concerned. Crucially though it accepts any arguments required by the target method as an array. So why is this useful Occasionally you are given arguments in array form. Unless you know in advance the number of arguments you are dealing