I want to create a set that holds mock java objects.Like the following
MyObject objectA = mock(MyObject.class);
when(objectA.getName()).thenReturn("nameA");
MyObject objectB = mock(MyObject.class);
when(objectB.getName()).thenReturn("nameB");
MyObject objectC = mock(MyObject.class);
when(objectC.getName()).thenReturn("nameC");
Set<MyObject> mySet = new HashSet<>();
mySet.add(objectA);
mySet.add(objectB);
mySet.add(objectC);
mySet.size();// this will be "1" instead of "3"
I want the size of the set to be "3" instead of "1".
I know that when adding an object to set it will verify hashcode of the object. In this case all of my mock objects have same hash code so the set is able to hold only one value.
I had also tried the following
int someRandomInt = 12345;
when(objectA.hashCode()).thenReturn(someRandomInt):
But Mockito fails to stub out private final methods.
How can I have a set that holds different mock objects ?
You can use IdentityHashMap class instead of HashSet. It uses reference comparison instead of equals methods so objects with different addresses will not be considered equal by this class.
Related
I am using Nomin for mapping tasks. As taken from the documentation of Nomin it should be able to map fields with the same name by itself in case automapping has been activated. When activating it, it causes an infinite loop exception.
I have the following:
mappingFor a: CoinsOnMarketPlace, b: Coin
// automap() // when deactivated it works fine, when activated infinite loop
a.coin.name = b.name
a.coin.rank = b.rank
a.priceUSD = b.priceUSD // Could be automapped
a.priceBTC = b.priceBTC // Could be automapped
...
Exception:
org.nomin.core.NominException: ./net/hemisoft/ccm/repository/coinmarketcap2coin.groovy: Recursive mapping rule a = b causes infinite loop!
One thing worth adding regarding your use case - this Recursive mapping rule a = b causes infinite loop! exception is thrown because you use groovy classes in your mapping rule. Nomin uses ReflectionIntrospector and what's important:
It performs getting/setting properties using accessor methods which are called through the Java reflection mechanism. ReflectionIntrospector uses supplied NamingPolicy instance to determine accessor methods. JbNamingPolicy is used by default, this implementation cerresponds the JavaBeans convention. Its InstanceCreator named ReflectionInstanceCreator instantiates objects using Class.newInstance().
Source: http://nomin.sourceforge.net/introspectors.html
A simple Groovy class like:
class Entity {
String name
String somethingElse
}
gets compiled to a Java class that implements GroovyObject providing following methods:
public interface GroovyObject {
Object invokeMethod(String var1, Object var2);
Object getProperty(String var1);
void setProperty(String var1, Object var2);
MetaClass getMetaClass();
void setMetaClass(MetaClass var1);
}
In this case ReflectionInstanceCreator combined with automap() resolves following mappings:
a.property = b.property
and
a = b
where a = b mapping comes from MetaClass getMetaClass() getter method I suppose, because there is no mapping like a.metaClass = b.metaClass resolved. a.property = b.property gets resolved because of Object getProperty(String var1) method.
Solution
This problem can be solved by specifying explicitly ExplodingIntrospector for your mapping script that:
It performs getting/setting properties using a class field immediately through through the Java reflection mechanism and may be useful in case when domain object don't provide accessors for their properties. Supplied instance creator is ReflectionInstanceCreator.
Source: http://nomin.sourceforge.net/introspectors.html
All you have to do is to add
introspector exploding
right below mappingFor a: ..., b: ... header. For example:
import mypackage.Entity
import mypackage.EntityDto
mappingFor a: Entity, b: EntityDto
introspector exploding
automap()
a.test2 = b.test1
Tested with two Groovy classes, worked like a charm. Hope it helps.
One for the gurus, please convince me/us what is going on.
List<ExpandoObject> peopleList = new List<ExpandoObject>();
dynamic expandoObj1 = new ExpandoObject();
expandoObj1.id = 1;
expandoObj1.first = "fred";
expandoObj1.last = "krugger";
peopleList.Add(expandoObj1);
dynamic expandoObj2 = new ExpandoObject();
expandoObj2.id = 2;
expandoObj2.first = "george";
expandoObj2.last = "benson";
peopleList.Add(expandoObj2);
//test access the props
var expObj = expandoObj1;
var name = expObj.first;
var expObj2 = peopleList[0] as dynamic;
var name2 = expObj2.first;
IDictionary<string, object> expObj3 = peopleList[0] as ExpandoObject;
var name3 = expObj3["first"];
var expObj4 = peopleList[0] as ExpandoObject;
//var name4 = expObj4.first; //THIS DOESN'T WORK - ExpandoObject does not contain a definition for 'first' etc...
In all cases, the LEFT-HAND SIDE is a System.Dynamic.ExpandoObject;
Why then, on the 4th case expObj4, i cannot access the property expObj4.first ?
ExpandoObject is a sealed class which stores data in a dictionary. It implements IDynamicMetaObjectProvider interface which provides dynamic behaviour to the classes implementing it. It also implements IDictionary interface which provides dictionary like behaviour to it. It is supposed to be checked and validated at compile time.
dynamic is a type which is not supposed to be checked by the compiler at compile time. It is checked and breaks at runtime. At compile time, a dynamic entity is assumed to support any operation. So, when you say, it is a expandoobject, the field called first does not get appended to object itself.
Check source code of expando object here
https://github.com/Microsoft/referencesource/blob/master/System.Core/Microsoft/Scripting/Actions/ExpandoObject.cs
Think of dynamic behavior like an object. You can put any type there. When you are adding to list, you are adding to list as dynamic, but the inherent type of item being added is ExpandoObject. So, you are able to cast it back to ExpandoObject.
When you say,
expandoObj1.first = "fred";
it is same as saying,
expandoObj1.Add("first", "fred");
When you used
var expObj = expandoObj1;
var name = expObj.first;
you were using expandoObject in dynamic form. So, you were able to access properties directly. When you cast it to ExpandoObject class, you were using actual ExpandoObject class which stores fields in Dictionary, so dot(.) notation does not work.
var expObj4 = peopleList[0] as ExpandoObject;
variable on left hand side is still ExpandoObject, not a dictionary. ExpandoObject exposes its members through collection search.
var name4 = expObj4.Where(t=>t.Key == "first").First().Value;
When you cast it to a dictionary, it works like a dictionary.
IDictionary<string, object> expObj3 = peopleList[0] as ExpandoObject;
var name3 = expObj3["first"];
When you cast it to a dynamic, you can access these keys like they are properties of the class.
Further reference
Dynamically adding properties to an ExpandoObject
This is because the variable expObj4 is declared as ExpandoObject and not as dynamic. This is an important difference.
Try this:
dynamic a = new ExpandoObject();
a.Name = "Test";
This compiles, but the following doesn't:
ExpandoObject a = new ExpandoObject();
a.Name = "Test";
you get this:
CS1061 'ExpandoObject' does not contain a definition for 'Name' and no extension method 'Name' accepting a first argument of type 'ExpandoObject' could be found
The variables you have that are related to this are:
expandoObj1 - dynamic
expandoObj2 - dynamic
expObj1 - dynamic
expObj2 - dynamic
expObj3 - dictionary, but you use dictionary access here, not dot-access
The magic "let's see if we can access the thing at runtime" code of the compiler only kicks in if the expression or variable is dynamic. ExpandoObject is just a type that supports this.
I am trying to add all elements of an object into ArrayList. elements of the object are of different type.
e.g. object Employee having attributes like emp_id,name,address,DOB.
I want to store each attribute as an object in an ArrayList. Like,
ArrayList[1] = Employee.emp_id
ArrayList[2] = Employee.name
ArrayList[3] = Employee.address
I want to do it dynamically. Like, in future more attributes are added in this object, without doing a manual work. Is there a way to create an array List?
ArrayList must be of the same type. You can have an ArrayList of type in which you can do what you are doing, since all objects in Java extend Object. If you are trying to store different Object types in an arraylist, however, this is not possible.
You may know that first part, just was a little unclear in your post.
Here's how to do it with objects using reflection:
//make sure you import java.lang.reflect.*
public void addMyFields(Employee e){
ArrayList<Object> list = new ArrayList();
for (Field field : emp.getClass().getDeclaredFields())
{
field.setAccessible(true);
list.add(field.get(emp);
}
}
Scenario:
I have x number of classes. Lets say 10; Each class does different UI Functions. When a user loads a file, that extension tells the program the classname to load; but it's in the form of a string.
Is there anyway to pass a string off as a classname? Something to the effect of.
var classname = "Booger";
var nose = new classname(){ //classname really means "Booger"
//Do Operation
}
You can reflect a type by name using var t = Type.from_name(classname);, however, this works on all types, including enums and structs and it might be the type Type.INVALID. You should probably do some checks, like t.is_a(typeof(MyParentClass)).
You can then instantiate a copy using var obj = Object.new(t);. The whole thing would look like:
var classname = "Booger";
var t = Type.from_name(classname);
if (t.is_a(typeof(MyParentClass)))
return Object.new(t);
else
return null;
It's also worth noting that the run-time type names have the namespace prepended, so you might want to do "MyNs" + classname. You can check in either the generated C or doing typeof(MyClass).name().
I've had the same problem as the OP in regards to getting an assertion error against null. If you take a look at the Glib documentation (in C) it mentions you have to register your class by actually specifying the class name first before you can actually use a string representation of your class name.
In other words you have to use your class first BEFORE you can instantiate a copy of your class with Glib.Type.from_name ("ClassName").
You can use your class first by instantiating a class instance or by getting type information for your class.
var type = typeof (MyClass);
var type_from_string = Type.from_name ("MyClass");
Furthermore, when you use Object.new to create a class there are two things you need to be aware of:
1) You need to cast the return value to get your specific class or base class.
var instance_of_my_class = Object.new (type) as MyClass;
2) Constructors for your class will no longer be called (I don't why). You will need to use the GObject style constructor inside your class:
construct {
pizza = 5;
}
I am trying to understand c# dynamic. I have an ExpandoObject instance assigned to dynamic variable.
I understand ExpandoObject is implementing IDictionary. But the below assignment fails.
dynamic obj = new ExpandoObject();
obj["Test"] = "TestValue";
Console.WriteLine(obj.Test);
Can someone tell me where i am going wrong?
obj.Test="TestValue";
However the above statement seems to be working fine.
To do that, you need to cast the ExpandoObject to IDictionary<string, object>.
This is normal Expando usage:
obj.Test = "TestValue";
This is string-literal (or string variable) usage:
var d = (IDictionary<string, object>)obj;
d["Test"] = "TestValue";
string s = "Test";
d[s] = "TestValue";
If the interface implementation is explicit, you need to cast to a reference of the interface in order to access the members. I'm guessing this is what has happened here.