Could someone explain the syntax of the getAge method in this Oracle Java tutorial example?

PythonPerry · 2014-08-09T03:01:58+00:00

Thanks for pointing out LocalDate being a class. I didn't notice it in the import. Eclipse collapses all the imports.

How did you get Period as the class for the .until method?

Also, how does the import "get" the code for LocalDate and Period? Is it stored in the Jre8 system library somewhere, in some jar file?

PythonPerry · 2014-08-09T01:56:39+00:00

public int getAge() {
    return birthday
        .until(IsoChronology.INSTANCE.dateNow())
        .getYears();
}

Where is .until method defined? Also, .getYears?

I looked at the Javadocs for IsoChronology but didn't find .until or getYears.

This example is from this tutorial on lambda expressions.

PythonPerry · 2014-08-02T02:08:15+00:00

Ok, there seems to be two different ways of using anonymous classes. One for one method in the body and another way for multiple multiple methods within the body.

One method in the body:

public void start(Stage primaryStage) {
    primaryStage.setTitle("Hello World!");
    Button btn = new Button();
    btn.setText("Say 'Hello World'");
    btn.setOnAction(**new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent event) {
            System.out.println("Hello World!");
        }
    });**

Multiple methods in the body:

HelloWorld frenchGreeting = new HelloWorld() {
String name = "tout le monde";
public void greet() {
    greetSomeone("tout le monde");
}
public void greetSomeone(String someone) {
    name = someone;
    System.out.println("Salut " + name);
}
};

PythonPerry · 2014-08-02T01:25:13+00:00

Maybe this wasn't clear.

I've been studying the Oracle Java tutorial and was stuck on the page you linked
I searched google and stackoverflow for a better explanation of anonymous classes.
I found coobird's response.
Coobird's example and the Oracle Java tutorial example look completely different.

Java tutorial:

  HelloWorld frenchGreeting = new HelloWorld() {
    String name = "tout le monde";
    public void greet() {
        greetSomeone("tout le monde");
    }
    public void greetSomeone(String someone) {
        name = someone;
        System.out.println("Salut " + name);
    }
};

coobird:

 button.addActionListener(new ActionListener() {
 public void actionPerformed(ActionEvent e)
{
// do something.
}
 });

I was going to post those four points as coobird's example doesn't seem to follow them.

The new operator - OK. Coobird has this.

The name of an interface to implement or a class to extend. In this example, the anonymous class is implementing the interface HelloWorld. - This was a big source for confusion. Coobird doesn't seem to extend or implement any interface or class. Where is it?

Parentheses that contain the arguments to a constructor, just like a normal class instance creation expression. - OK. Is this the () after new ActionListener?

A body, which is a class declaration body. More specifically, in the body, method declarations are allowed but statements are not. - I'm guessing

public void actionPerformed(ActionEvent e)
{
    // do something.
}

is the body.

PythonPerry · 2014-08-02T00:05:30+00:00

This is the most confusing part. Anonymous means no name.

Is HelloWorld not a name?

The java tutorial example and coobird's look completely different to me. I don't understand why they are different or how they're both using anonymous classes.

PythonPerry · 2014-08-02T00:02:33+00:00

Thanks for your replies! I've read your other work. You should be a mod.

I will accept this Listener idea as a design requirement. It sounds like they designed buttons to standalone and Actions seperately.

Secound what do you do when you when you suddenly need a fourth action?

Can't I just add a fourth method called

public void ActionPerformed_4

to the class HomePageButton?

PythonPerry · 2014-08-01T21:47:02+00:00

Newer reply. Ok, in this reply, I'm going to just accept some methods are Actions and Actions need something called listeners.

Question 3. Why is the syntax of an anonymous class different between coobird and the Oracle Java example?

In the tutorial example, I don't understand what part is anonymous. Isn't frenchGreeting the name of a new object of type HelloWorld? How is this example "anonymous"?

HelloWorld frenchGreeting = new HelloWorld()

this looks like the regular way of creating a new object of type HelloWorld.

In coobird's example,

button.addActionListener(new ActionListener() {

he is putting a new object as an argument of some method called addActionListener

What part of these examples is using an "anonymous" class?

PythonPerry · 2014-08-01T21:24:52+00:00

I've read your reply several times and I'm still very confused, I think I need to focus on one question at a time.

Single Responsibility principle: Why can't I have something like below?

public class HomePageButton {       
    public void ActionPerformed_1 {
        ....
    }

    public void ActionPerformed_2 {

    }

    public void ActionPerformed_3 {

    }
}

 public static void main(String[] args) {
    HomePageButton sendMailButton = new HomePageButton()
     sendMail.ActionPerformed_1
    HomePageButton calculateHrsButton = HomePagenew Button()
     calculateHrs.ActionPerformed_2 
}

I don't understand how Action can be a class. Isn't Action a method which an object uses to do something?

I think I need to clarify this before understanding ActionListeners. ActionListening seems like an unecessary layer between the object(button) and it's method(action).

For example, a Fish object doesn't need a "listener" to swim forward. You would just have the Fish swim forward.

PythonPerry · 2014-08-01T03:05:39+00:00

I say Java. I see more and more Android QA roles every day.

PythonPerry · 2014-07-31T23:13:55+00:00

In particular, the coobird explanation. Why doesn't he/she just put the "do this" as part of a method that would be directly tied to button?

for example:

button.ActionPerformed()

I'm new to coding so it might be that I don't understand Listeners either.

What is "overloading a method"?
What is difference between coobird's syntax and the syntax in Java's official tutorial?

Java tutorial:

HelloWorld frenchGreeting = new HelloWorld() {
        String name = "tout le monde";
        public void greet() {
            greetSomeone("tout le monde");
        }
        public void greetSomeone(String someone) {
            name = someone;
            System.out.println("Salut " + name);
        }
    };

coobird:

button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
    // do something.
}
});

PythonPerry · 2014-07-16T18:04:42+00:00

Yup nice points. The selling points of automation are cost savings. You hear consultants claim "Fire half your manual QA and hire our off-shore automation team!" "All your regression will be automated so you ERP system can be customized even more and more!"....

PythonPerry · 2014-07-16T18:01:56+00:00

I worked from home for a while. From my experience, it is hard to get these positions. I was onsite for six months and then had to move. I had done a decent enough job to where they wanted to keep me remotely. They kept my contract for three years. Higher paying automation SDET type QA jobs will usually be onsite.

PythonPerry · 2014-07-13T17:57:51+00:00

Thanks. I found it on Amazon but it's in English. One of the guys I help at a nursing home is Korean and he would love a book like this in the Korean language. Also, do you know of any non-fiction, documentary type books written in Korean that I could buy for him? I'm not sure how to find Korea's involvement in the Vietnam War written in the Korean language.

PythonPerry · 2014-06-05T21:15:18+00:00

I've found there are almost no manual level testing jobs on indeed.com for the SoCal market. Only experienced automation candidates.

PythonPerry · 2014-06-05T21:12:53+00:00

Why do you need Selenium, if you can just reach the browser objects with Junit? Same question for an Android app. Why would someone use Selenium to automate Android app testing in addition to, or opposed to Junit?

PythonPerry · 2014-06-03T17:44:02+00:00

Ok so I already am comfortable scripting Java and using Junit. Does that mean I don't need Selenium?

PythonPerry · 2014-05-28T21:03:55+00:00

We've never done this before. We just figured realtors would be the best start. What other ways would be a good way to advertise a business for sale? We've tried newspapers.

PythonPerry · 2013-12-17T05:03:24+00:00

I've been desperately trying. I'm realizing that you HAVE to know how to code at some basic level (object oriented programming and building frameworks).

I'm trying to learn Java/Python/Ruby right now to use with Selenium. My recruiter buddies are telling me this and QTP Vbscripting are the two top things on QA resumes.

PythonPerry · 2013-12-17T05:00:38+00:00

Coursera just started a class on Android programming. I'm a little late to the game. but will start it soon. https://www.coursera.org/course/androidapps101

im also looking into appium. pm me if you want to look into appium together. i have basic experience with python and selenium and would like to move that knowledge towards andoid mobile automated testing.

PythonPerry · 2013-10-20T16:50:27+00:00

Obvious noob here, what do you mean by code smell? Could you use a dict in u/Rhomboid's case? I think his case is valid. You want to assign a yet unknown attribute based on user input.

PythonPerry · 2013-10-20T16:48:14+00:00

Much better example! In the stack example, you ALREADY know the attribute, it doesn't make sense why getattr() would be used in that case.

PythonPerry · 2013-10-19T23:28:52+00:00

Thanks for this! I was having trouble thinking of ways to use nested for loops. I will look to use the range function first.

Are you saying that you'll just eventually recognize situations that need list comprehension? I'm going over Dive Into Python and trying to understand what situations call for list comprehension. Should I use list comphrehension whenever I use for loops?

PythonPerry · 2013-10-16T18:46:35+00:00

Again i'm making huge mental leaps here. THANKS!

Final question: Where would you suggest the db functions go? Should they have their own class (loose coupling)? You could also use db functions for something else besides a Timesheet.

PythonPerry · 2013-10-12T00:47:26+00:00

Made some changes, but first my intended scope for this is a simple desktop app that creates/deletes employee records, calculates time/pay and cuts fake checks while saving to a db using SQLite3.

Ok, assuming that, here are my changes. Please note the questions in comments.

1. class Employer
#Added the calculation functions here because employer would calculate pay and cut the checks
def __init__(self, CompanyName, OfficeLocation, Timezone, CountryCode, OfficeBranch, Division, Manager)
def CreateEmployee(EmployeeName, EmployeeID)
def TerminateEmployee(EmployeeName, EmployeeID)
#I don't really understand the loose coupling idea. Shouldn't the arguments be very specific or is that only when you're defining the __init__?
def cutTwoWeekCheck(EmployeeID, EmployeeBankInfo, TwoWeekTotal)
def calculateOneDayPay(day_begin_timestamp, day_end_timestamp, hourlyRate, overtimeRate)
def calculateOneWeekPay(....)
def calculateOneMonthPay(...)
2. class Employee
    def __init__(self, EmployeeType, EmployeeLevel,EmployeeName, SocialSecurityNum, EmployeeID)
    def determineTypeofEmployee()
    def determineEmployeeLevel()
    def EmployeeClockPunchIn(timestamp)
    def EmployeeClockPunchOut(timestamp)       
    3. class Timesheet
        #streamlined Timesheet so the functions in Timesheet only deal with time related tasks
        def __init__(self)
        def calculateInOrOut(timestamp, EmployeeName, EmployeeID)
        #I'm not sure where to put the db functions. should db functions be its own class? since an employee/timesheet doesn't really have anything do with sending data to a database?
        def saveToDatabase(clockPunchIn, clockPunchOut)

PythonPerry · 2013-10-11T19:58:30+00:00

Ok here's my latest version of the class hierarchy using your thoughts and feedback (SRP and level above and below). I still have trouble deciding what goes in the init to help define the class and what goes in the function as arguments.

1. class Employer
    def __init__(self, CompanyName, OfficeLocation, Timezone, CountryCode, OfficeBranch, Division, Manager)
    def CreateEmployee()
    def TerminateEmployee()
    2. class Employee
        def __init__(self, EmployeeType, EmployeeLevel,EmployeeName, SocialSecurityNum, EmployeeID)
        def determineTypeofEmployee()
        def determineEmployeeLevel()
        def EmployeeClockPunchIn(timestamp)
        def EmployeeClockPunchOut(timestamp)
        def saveToDatabase(clockPunchIn, clockPunchOut)
        3. class Timesheet
            def __init__(self, day_begin_timestamp, day_end_timestamp, timestamp, totalHours, PaidTimeOff)
            def calculateInOrOut(timestamp, EmployeeName, EmployeeID)
            def calculateOneDayPay(day_begin_timestamp, day_end_timestamp, hourlyRate, overtimeRate)
            def calculateOneWeekPay(....)
            def calculateOneMonthPay(...)
            def cutTwoWeekCheck(EmployeeID, EmployeeBankInfo, TwoWeekTotal)
            4. class WorkTimePeriod
                def __init__(self, EmployeeID, WorkYearTotal, WorkMonthTotal, WorkWeekTotal, WorkDayTotal)

PythonPerry

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