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assertThat field by field or compare object

I'm having an argument with my friend and I would like to know your opinion.
In a test do you think that is better to compare field by field or just create a expectedResultObject and compare it.
For instance:
Assert.That(obj.Foo).isEqualTo(FOO);
Assert.That(obj.Test).isEqualTo(TEST);
vs
Foo expected = new Foo(FOO, TEST);
assertThat(obj).usingRecursiveComparison().isEqualTo(expected);
In this example we only have two fields but we can have allot more.
Thanks

If you can have multiple fields, the expected method is better because you'll be adding the other fields inside the constructors' params. Imagine if you have 100 fields, adding them line by line as you suggested in your first example would be a headache, while adding in the params would be a bit simpler.

Between the two possibilities, I prefer the one without the usingRecursiveComparison().
I wanted to add a few thins :
An object is not a data toolbox, so it's not a good thing to add getter/setter to test your object's creation. It's better test a behaviour, a method where you can test the return.
Generally I'm not fond of writing more than one assertion in a test.
There is a technique which made assertions more lisibles (with AssertJ but I think you can make this kind of thing with Hamcrest).
The initial class :
public class Amount {
private int value;
public Integer add(int amountToAdd) {
value += amountToAdd;
return value;
}
}
Create an Asserter :
public class IntegerAsserter extends org.assertj.core.api.AbstractAssert<IntegerAsserter, Integer> {
IntegerAsserter(Integer actual) {
super(IntegerAsserter.class, actual);
}
public IntegerAsserter isBetweenOneOrTwo() {
Assert.assertTrue(actual < 2);
Assert.assertTrue(actual > 1);
return this;
}
}
Create a new Assertions :
public class Assertions extends org.fest.assertions.Assertions {
public static IntegerAsserter assertThat(Integer actual) {
return new IntegerAsserter(actual);
}
}
And then use it :
public void should_be_between_one_or_two {
Amount amount = new Amount(0);
Integer newAmount = amount.add(1);
Assertions.assertThat(obj).isBetweenOneOrTwo();
}

JComboBox fill with enum variable value

I have a JComboBox that I made this way, using an enum for its values:
JComboBox<StudyGrade> maxLevelOfStudiesCombo = new JComboBox<StudyGrade>(StudyGrade.values());
The enum looks like this:
public enum StudyGrade {
ELEMENTARY ("Primaria"),
MIDDLE ("Secundaria"),
MIDDLE_HIGH ("Preparatoria"),
HIGH ("Universidad"),
MASTERS ("Maestría / Posgrado"),
DOCTORATE ("Doctorado"),
POST_DOCTORATE ("Post Doctorado");
private String studies;
private StudyGrade(String studies) {
this.studies = studies;
}
public String getStudies() {
return studies;
}
public void setStudies(String studies) {
this.studies = studies;
}
#Override
public String toString() {
return studies;
}
}
As you can see I'm overriding the toString() method, so I can have the studies values shown instead of the enum ones...
However I want to show the studies values only in the JComboBox not everytime I use the StudyGrade enum.
How would I change the code, so whenever I use something like:
System.out.println(StudyGrade.HIGH);
I get printed HIGH instead of Universidad, but not for the JComboBox?

I'm overriding the toString() method, so I can have the studies values shown instead of the enum ones...
I've never used a enum before but I assume you can use it like any custom object added to the combo box so you should be able to use a custom renderer so you can control which data is displayed by the combo box.
Check out Combo Box With Custom Renderer for more information and a helper class.

You're looking to extend an enum, but that's impossible. It means that something is wrong with your requirement.
Rendering is done in the UI component, and it's not enum's business to deal with presentation of data. You should make you UI component render enum the way you'd like instead of trying to make enum understand where it's being used. Since you're a Swing fanatic you should know how to do that, something like this:
maxLevelOfStudiesCombo.setRenderer(new DefaultListCellRenderer() {
#Override
public Component getListCellRendererComponent(JList<?> jList, Object o, int i, boolean b, boolean b1) {
Component rendererComponent = super.getListCellRendererComponent(jList, o, i, b, b1);
setText(o instanceof StudyGrade ? ((StudyGrade) o).getStudies() : o.toString());
return rendererComponent;
}
});
That's going to do that.

You could just remove the toString override as the default toString for an enum is to return the name of the enum element.
And you could just have a simple for loop that would iterate through the values in your enums and add it to a string array. Then, you would need to pass that array as the argument for your JComboBox and it should be gold.
The code for it should look a bit like that:
//get all study grades
StudyGrade[] temp = StudyGrade.values();
//create a string array of same length as the array
String[] str = new String[temp.length];
//append all the studies value to the string array
for(int i = 0; i< temp.length; i++){
str[i] = temp[i].getStudies();
System.out.println(temp[i]);//debug
}
System.out.println("---------------------");//debug
for(String s : str){//debug
System.out.println(s);//debug
}//debug
//pass it
JComboBox<StudyGrade> maxLevelOfStudiesCombo = new JComboBox<StudyGrade>(StudyGrade.values());
Here is an example I made on repl.it
https://repl.it/GH28/1

How can i make constructor without fields with enum?

I don't have idea how to add to array enum. I made constructor using fields with enum and its works, but I don't know how to make it in constructor without field. I hope that you understand what Im thinking about. In my code I comment where I think i have problem.
I've got:
public enum Components {
WIFI, BLUETOOTH, CAMERA, SSD
}
public Laptop(){
System.out.println("name of producer:");
String producername = Main.sc.nextLine();
System.out.println("name of model:");
String modelname = Main.sc.nextLine();
System.out.println("ram:");
int ram = Main.sc.nextInt();
System.out.println("cpu:");
String cpu = Main.sc.nextLine();
cpu = Main.sc.nextLine();
System.out.println("components:");
System.out.println("how many components do you want to add?");
int z = Main.sc.nextInt();
Components[] com = new Components[z];
for(int i=0; i<com.length;i++){
com[i] = //<-- how to add enum in array?
}
setProducerName(producername);
setModelName(modelname);
setRam(ram);
setCpu(cpu);
setComponents(com);
}
My constructor using field is like that and it works.
public Laptop(String ProducerName, String ModelName, int Ram, String Cpu, Components... components) {
super();
this.ProducerName= ProducerName;
this.ModelName= ModelName;
this.Ram= Ram;
this.Cpu= Cpu;
this.components= new Components[components.length];
this.components= Arrays.copyOf(components, components.length);
}
Please help.

You could get the enum value by its name.
public enum Components {
WIFI, BLUETOOTH, CAMERA, SSD
}
public Laptop(){
...
Components[] com = new Components[z];
for(int i=0; i<com.length;i++){
com[i] = Components.valueOf(Main.sc.nextLine());
}
...
}

I'm not 100% clear what you're asking, but you can get an array filled with your enum constants from the enum itself: Components.values() will return an array of all the enum constants. It will essentially return:
new Components[]{Components.WIFI, Components.BLUETOOTH,
Components.CAMERA, Components.SSD}
Side recommendation: don't use Scanner inside of your Laptop constructor, and in fact, get all user interface code out of all constructors and instance methods of that class. All user interface code belongs elsewhere.

Java reflection nested methods not modifying underlying object

I am taking in an array of methods and I want to chain them together to modify an object that I am working in.
For example I start with
"getStuff().get(1).get(3).setMoreStuff().put(stuff,6)"
I split it into an array called methods, and clean up the parameters inside each method and I try to modify this.
Object res = this;
String[] methods = targetString.split("\\.(?=\\D)");
for (String m : methods){
List<Object> params = new ArrayList<Object>();
List<Object> params = new ArrayList<Object>();
for (String p : m.split("\\(|,|\\)")) {
try {
if (p.indexOf(".") != -1){
double tempD = Double.parseDouble(p);
params.add(tempD);
} else {
int tempP = Integer.parseInt(p);
params.add(tempP);
}
} catch (Exception ex) { //not a number
params.add(p);
}
}
switch (params.size()) {
case 1:
res = res.getClass().getMethod(
params.get(0)
).invoke(res);
break;
case 2:
res = res.getClass().getMethod(
params.get(0),
params.get(1).getClass()
).invoke(res, params.get(1));
break;
case 3:
res = res.getClass().getMethod(
params.get(0),
params.get(1).getClass(),
params.get(2).getClass()
).invoke(res, params.get(1), params.get(2));
break;
}
in the end I notice that res has been modified the way that I expect. All the getters and setters are called correctly. But of course the underlying object "this" refers to has not been changed!
I guess I'm just calling the getters and setters of the copy I made in the first line!
now I can't just use
this.getClass().getMethod(...).invoke(...)
because I need to call the same getMethod on the object returned by this call.
To clarify:
Object res = this;
creates a "pointer" to this. So that when I call
res.getStuff().setStuff(foo)
this will also be modified.
but it seem that when I call
res = res.getStuff();
res = res.setStuff();
like I do in my loop,
this does not modify the underlying object this refers to?
Edit: Included more code as per request.
Edit2: added anther example, to clarify my problem.
Edit3: tried to add more code, its a bit hard to add a working program without including every class

Your general approach should be fine (although your approach to parameter conversion is somewhat ugly) - it's the specifics that are presumably causing you problems. Here's a short but complete program demonstrating calling methods and then seeing the difference afterwards:
import java.lang.reflect.*;
class Person {
private String name = "default";
public String getName() {
return name;
}
// Obviously this would normally take a parameter
public void setName() {
name = "name has been set";
}
}
class Test {
private Person person = new Person();
public Person getPerson() {
return person;
}
// Note that we're only declaring throws Exception for convenience
// here - diagnostic code only, *not* production code!
public void callMethods(String... methodNames) throws Exception {
Object res = this;
for (String methodName : methodNames) {
Method method = res.getClass().getMethod(methodName);
res = method.invoke(res);
}
}
public static void main(String[] args) throws Exception {
Test test = new Test();
test.callMethods("getPerson", "setName");
System.out.println(test.getPerson().getName());
}
}
The output is "name has been set" just as I'd expect. So see if you can simplify your code bit by bit, removing extra dependencies etc until you've got something similarly short but complete, but which doesn't work. I suspect you'll actually find the problem as you go.

Object does not change reference, its VALUE changes. So if you will call this.get("some key"), you will get value that the same value that you put using reflection.
Right?

Casting inner objects in java - unchecked exception

I'm having a problem with inner classes. I build an object (let's say a train) with an inner class representing states (let's say the stops of the train).
I'm trying to run this code:
private void CustomObjectBuilder (String [] origin) {
final int array_dim = origin.length;
InnerCustomObject[] tmp_bin = new InnerCustomObject[array_dim];
for (int ii = 0; ii < array_dim; ii++) {
String debug = extractData(origin[ii]);
tmp_bin[ii].setData(debug);
}
}
It compiles just just fine but at runtime I get a null object exception.
What am I doing wrong?
Here you can finde the original code:
public class CustomObject {
InnerCustomObject [] stops;
public class InnerCustomObject {
String name, station, schedTime, depTime, schedRail, depRail;
public void setData (String origin) {
this.station = origin;
}
}
}
Edit: I solved by calling
CustomObject.InnerCustomObject ico = new CustomObject(). new InnerCustomObject();
why it needs to be so verbose?

Well, the most immediate thing I notice is you don't populate tmp_bin[] with any objects after you declare it. When you first create an array, all it contains are nulls.
So when you do this in your loop:
tmp_bin[ii].setData(debug);
There is nothing to invoke setData() on, resulting in the exception.
Re edit: you can just do
InnerCustomObject ico = this.new InnerCustomObject();
since you're creating them within your outer CustomObject class's CustomObjectBuilder() instance method.

InnerCustomObject[] tmp_bin = new InnerCustomObject[array_dim];
declares an array of array_dim elements but all are null. Then this
tmp_bin[ii].setData(debug);
won't work.
No problem with inner classes only with an object that is null (=NPE) so you cannot call the method setData().

In your loop you have to create new instance of InnerCustomObject. By new InnerCustomObject[size] you do not create new instances.