We are using Spring MVC, in that for one particular module one controller class is their and for different pages of that module we have different method in the same class.
Every thing works fine but we want some code (i.e. for page history and other logs) to use in all methods. Currently we are copy pasting that code in all methods but want some good solution that we reuse the code block.
Write a static method in under a class name Utils and use it everywhere
Utils.method();
Related
I work with a codebase where there are many classes with thousands of lines of code. I've noticed inconsistencies in style concerning prepending class names when using their methods and I'm trying to figure out the previous developer's reasoning. If we
import GeneralCode
in Class A, is it bad practice to write
GeneralCode.DoSomething()
in Class A since we already imported it (instead of simply using DoSomething())? I would think so, but I suppose it's also nice to know which methods come from which classes at a glance, since Class A imports many classes and uses methods from several of them.
EDIT: This is for VB.NET, not Java (sorry for the wrong tag, rough morning). I am new to VB.NET but GeneralCode and DoSomething() are not declared as static, neither is the import in Class A.
Might be something to do with VB.NET, but DoSomething() can indeed be used with or without prepending GeneralCode.
A method need to be prefixed with
The class name if it's a static method.
The name of the instance when it's not a static method.
Unless you are calling a method from your own class.
There's a solid chance I'm misusing classes here which is why I need your help.
I've started developing with Java EE and one of the problems I am facing is I have a process which I have organised in a class, call it: "SendEmail.java".
Now let's say I have two other classes called "Thunderalert.java" and "FloodAlert.java" which will use all the methods that SendEmails.java has within it.
So I want to know the best way of using the SendEmails methods from each of the other classes.
Should I be creating an instance of SendEmails and accessing each method individually and error checking along the way (what if an exception is thrown?).. It's methods are just procedural code, so it's not really an 'object' as such
Shall I just be using the one method that runs all the other internal ones from within SendMail
Should this SendMail be redesigned as a helper class-type design?
I'm still quite new at Java EE so I'm not sure if there are any options available which I am missing
I think you should have one public method inside SendEmail class.
Btw, I would consider changing its name. I think having method send() when class is called SendEmail is not the best way (not to mention about names like call(), invoke() etc).
This is great article about this problem (The Kingdom of Nouns) in java.
What about something like: new Email(recipient, body).send()?
Or if you want to do it in a service style, I'd call it for example MailService
I have a VB.net program that I received from someone else. I am trying to make modifications to it. The program consists of one main form and 6 classes (all .vb files).
In the main form, I want to call a sub-routine in one of the other modules. What is strange is that if I enter the name of the module followed by a ".", i.e.
QuoteMgr.
I don't see the names of the sub-routines in the module. I only see the Public Const's that are defined.
The sub-routine that I want to call is in a section labelled:
#Region "Methods"
What do I need to do to be able to call one of these methods?
The confusion was because of the wording you used in your original question before you edited it to say "class" instead of "module".
The two terms in VB.net mean entirely different things. A class typically must be insantiated as an object to invoke its methods.
So what you need to do is:
dim qt as new QuoteMgr
qt.Method("foo");
In this case you're creating an instance of QuoteMgr called qt and then invoking its methods. Alternatively you could modify the QuoteMgr class and set the method you're trying to call to "Shared" and then call it by simply going "QuoteMgr.Method" as you were trying before.
A module is more like a free-standing library of methods that can be called by anything in the same project (by default).
I have a Struts 1 application which works with Velocity as a template language. I shall replace Velocity with Freemarker, and am looking for something similar to 'toolbox.xml'-File from VelocityViewServlet. (there you can map names to Java Classes and, using these names it is possible to access methods and variables of various Java class in the Velocity template).
Does someone know, what is possible with Freemarker instead? So far I have found only information about the form beans...would be glad if someone can help....
For the utility functions and macros that are View-related (not Model-related), the standard practice is to implement them in FreeMarker and put them into one or more templates and #import (or #include) them. It's also possible to pull in TemplateDirectiveModel-s and TemplateMethodModelEx-es (these are similar to macros and function, but they are implemented in Java) into the template that you will #import/#inlcude as <#assign foo = 'com.example.Foo'?new()>.
As of calling plain static Java methods, you may use the ObjectWrapper's getStaticModels() (assuming it's a BeansWrapper subclass) and then get the required methods as TemplateMethodModelEx-es with staticModels.get("com.example.MyStatics"). Now that you have them, you can put them into the data-model (Velocity context) in the Controller, or pick methods from them in an #import-ed template, etc. Of course, you can also put POJO objects into the data-model so you can call their non-static methods.
The third method, which is not much different from putting things into the data-model is using "shared variables", which are variables (possibly including TemplateMethodModelEx-es and TemplateDirectiveModel-s) defined on the Configuration level.
Say you want to add a lengthOfFirstLine method to the predefined File class. Is it a better practice to modify the existing class, or make a new class that extends the File class with your new method?
EDIT -- Specifically, the situation is that a class is lacking one method in particular. I don't want to completely change the class, but rather augment it with that method.
It depends if the method is applicable to all elements of the class File. For instance, lengthOfFirstLine doesn't apply to binary files, so probably it doesn't belong in a generic File class, but if your class only represent text files, then it should go there.
For .NET languages, there's also the option of using extension methods. This way you don't have to "dirty up" a class by adding helper/utility methods to it, and no inheritance is required as well - you add functionality to a class by simply adding a using statement to your code.
Agree with Luis and Lester. If you are using .Net the extension methods are the way to go for this sort of functionality. But you should try not add LengthOfFirstLine to a base class if you can open all sorts of files such as binary files. You would sub class it to a FileClass and add the method to that.
Remember that the extension methods in .Net are syntactic sugar anyway. You can simulate it in your own language using Static classes and methods. This is what .Net does under the covers anyway.
For example have a static FileHelpers class and have various static helper methods on it. The first parameter for each of these static methods would be the File class. So you could call this using FileHelpers.GetLengthOfFirstLine(myOpenedFile)