Testing and Mocking ScalaGraph with gremlin - gremlin

I have a Service class that i am trying to unit test. The service class is as follows -:
class BtoService #Inject()(db: GrDbConnection,
businessService: BusinessService,
vertexIdGenerator: VertexIdGenerator) {
def updateBto(id: String, updateBTOReq: UpdateBTORequest) = {
implicit val g = db.g
val btoVertex = g
.V(
vertexIdGenerator.vertexId(VertexLabels.BTO, id, PropertyLabels.BTO_ID))
.headOption() match {
case Some(value) => value
case None => throw BtoDoesNotExistException(s"BTO $id Does not exists")
}
So while testing this class, i create a mock of injected services(BusinessService, GrDbConnection) -:
val db: GrDbConnection = mock[GrDbConnection]
val businessService: BusinessService = mock[BusinessService]
val vertexIdGenerator: VertexIdGenerator = mock[VertexIdGenerator]
val btoService: BtoService = new BtoService(db, businessService, vertexIdGenerator)
val g : ScalaGraph = EmptyGraph
.instance()
.asScala()
btoService.updateBto("101",updateBTORequest)
Mockito.when(db.g).thenReturn(g)
The GrDbConnection.scala has the defined db.g -:
val g: ScalaGraph = EmptyGraph
.instance()
.asScala
.configure(_.withRemote(connection))
here connection has the necessary details to connect to the actuall db.
Since i can return an empty scala graph using Mockito.when().thenReturn(), i preferred not to use .configure() option in my test class.
My real problem that i face is that, i am not able to add a vertex to the test graph, I need to add a btoModel as the vertex to the graph since, in service class :
val btoVertex = g.V(vertex......()).headOption() - returns a GremlinScala.Aux[scala.vertex, Hnil]
How do i proceed with that?
please contact me at - nilay0016#gmail.com for more info.

Related

Retrieve integer from Firebase child

I am trying to implement a counter for deals in my app. i am trying to recall the last integer written to the child e.g. deal number 10. i can successfully write a manually inputted value into firebase however i cannot retrieve the initial value.
i am using the following
dealnumRef = FirebaseDatabase.getInstance().reference
val numberRef = dealnumRef.child("Total_deals").orderByChild("deal_number")
val dealnumEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
for (ds in dataSnapshot.children) {
val deal_num =
ds.child("deal_number_cars").getValue()
d("current deal number",deal_num.toString())
val new_deal_num = deal_num + 1
the issue i have is that currently deal_num is pulling through as Any?. If i insert String::class.java into getvalue()it will bring it back as a string. But I need to keep it as an Integer to compute new_deal_num because new_deal_num will need to be written to the database and increment the deal_number to 11 as an example.
how do i extract deal_num as an integer?
I have checked available answers, but those indicate to convert to string. This would not work in my example, because i need to increment the deal number and hence keep it as an integer.
You can get the correct type from Firebase by passing its class into getValue(..).
So:
val deal_num = ds.child("deal_number_cars").getValue(Long.class)
If you're storing a number in deal_number_cars in the database, this will get that value as a long.
The Full correction to the above is as follows:
dealnumRef = FirebaseDatabase.getInstance().reference
val numberRef = dealnumRef.child("Total_deals").orderByChild("deal_number_cars")
val dealnumEventListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
for (ds in dataSnapshot.children) {
val deal_num =
ds.getValue(Long::class.java)!!
d("current deal number",deal_num.toString())
val new_deal_num = deal_num + 1
You also have to make sure that you data model class is set as Long. i originally had it set as Int which created a small problem but was easily resolved.

Mongoengine serialize dictionary (with nested dicts)?

I've created a dictionary from an Uploaded file in Django.
This dictionary has a nested list of dictionaries:
file = {"name": "filename", "sections": [{"section_name": "string", "lines": [{line_number: 0, "line"; "data"}]}], "etc": "etc"}
The model represents the dictionaries depth too.
class Line(EmbeddedDocument):
line_number = IntField()
line = StringField()
definition = ReferenceField(Definition)
class Section(EmbeddedDocument):
section_name = StringField()
lines = EmbeddedDocumentListField(Line))
class File(Document):
name = StringField()
sections = EmbeddedDocumentListField(Section))
created_on = DateTimeField()
created_by = StringField()
modified_on = DateTimeField()
modified_by = StringField()
In the POST I have the following to chop the file up into the above Dict (the file is a simple text file):
file= {}
with open(os.path.join(path, filename + ".txt"), 'r') as temp_file:
filelines = temp_file.readlines()
sections = []
section = {}
lines = []
for i, l in enumerate(filelines):
if i == 0:
section["section_name"] = "Top"
elif '*' in l:
if l.index('*') == 0 and '*' not in lines[len(lines) - 2"line"]:
section["lines"] = lines
lines = []
sections.append(section)
section = dict()
section["section_name"] = filelines[i + 1][1:-2]
line = {"line_number": i + 1, "line": l}
lines.append(line)
section['lines'] = lines
sections.append(section)
file["name"] = filename
file["sections"] = sections
I will tidy this up eventually.
Once the dict has been made how do I serialise it using the serializer?
Is it possible to insert this into a serializer?
If not how can I get it all into the database with validation?
I've tried json.dumps() and JsonRequst() then putting them in data= for the serializer but get Unable to get repr for <class '....'>
I'm pretty new to Django and MongoDB so if you need more info I can provide :)
Thanks!
Update
Change the model's List Fields to EmbeddedDocumentListField as suggest in the answer.
Answered
Thanks to Boris' suggestion below it pointed me to an error I wasn't getting initially. I had a typo and passing the dict directly into FileSerializer(data=file) works like a charm! :)
James!
The easiest way to validate that your incoming JSONs adhere to the Mongoengine Documents schema that you've specified is to use DRF-Mongoengine's DocumentSerializer.
Basically, what you need to do is create a serializer
serializers.py
import rest_framework_mongoengine
class FileSerializer(rest_framework_mongoengine.DocumentSerializer):
class Meta:
fields = '__all__'
model = File
Then you need a view or viewset that makes use of this Serializer to respond to GET/POST/PUT/DELETE requests.
views.py
from rest_framework_mongoengine import viewsets
class FileViewSet(viewsets.ModelViewSet):
lookup_field = 'id'
serializer_class = FileSerializer
def get_queryset(self):
return File.objects.all()
and register this viewset with a router
urls.py
from rest_framework import routers
# this is DRF router for REST API viewsets
router = routers.DefaultRouter()
# register REST API endpoints with DRF router
router.register(r'file', FileViewSet, r"file")
I'd also recommend using EmbeddedDocumentListField instead of ListField(EmbeddedDocumentField(Section)) - it has additional methods.

Akka Multi Node Testing available in Java?

I have read the Akka Java documentation about Multi Node Testing, however all codes are in Scala. Is there any reason for that? Google search was unsuccessful as well.
EDIT:
To reduce the tumbleweedness of this question, I did try :). A simple translation to Java of the existing Scala codes migth look like this:
public class ClusterTest {
protected RoleName first;
#Test
public void SimpleClusterListenerClusterJoinTest() throws Exception {
new MultiNodeSpec(new MultiNodeConfig() {{
first = this.role("first");
second = this.role("second");
third = this.role("third");
this.commonConfig(ConfigFactory.parseString(
"akka.crdt.convergent.leveldb.destroy-on-shutdown = on\n" +
"akka.actor.provider = akka.cluster.ClusterActorRefProvider\n" +
"akka.cluster.auto-join = off\n" +
"akka.cluster.auto-down = on\n" +
"akka.loggers = [\"akka.testkit.TestEventListener\"]\n" +
"akka.loglevel = INFO\n" +
"akka.remote.log-remote-lifecycle-events = off")); }}) {
{
Address firstAddress = node(first).address();
#SuppressWarnings("serial")
ArrayList<RoleName> firstnode = new ArrayList<RoleName>() {{
add(first);
}};
Seq<RoleName> fisrtnodeseq = (Seq<RoleName>)JavaConversions.asScalaBuffer(firstnode).toList();
runOn(fisrtnodeseq, null);
Cluster cluster = new Cluster((ExtendedActorSystem) system());
cluster.join(firstAddress);
// verify that single node becomes member
cluster.subscribe(testActor(), MemberEvent.class);
expectMsg(MemberUp.class);
}
#Override
public int initialParticipants() {
return roles().size();
}};
}
}
HOWEVER During the run with the arguments:
-Dmultinode.max-nodes=4 -Dmultinode.host=127.0.0.1 etc. according to Multi Node Testing (if I list here all of the arguments the editor heavily complains :[ ) I will get the following error:
java.lang.IllegalArgumentException: invalid ActorSystem name [ClusterTest_2], must contain only word characters (i.e. [a-zA-Z0-9] plus non-leading '-')
at akka.actor.ActorSystemImpl.<init>(ActorSystem.scala:497)
at akka.actor.ActorSystem$.apply(ActorSystem.scala:141)
at akka.actor.ActorSystem$.apply(ActorSystem.scala:118)
at akka.remote.testkit.MultiNodeSpec.<init>(MultiNodeSpec.scala:252)
at com.akkamint.demo.ClusterTest$2.<init>(ClusterTest.java:51)
is the internally generated ActorSystem name wrong?
Besides this I have two questions:
How can access the gossips from Java as in the Scala code,
awaitCond(Cluster(system).latestGossip.members.exists(m ⇒ m.address == firstAddress && m.status == Up))
and I have not found any way to implement the same in Java. My workaround is to subscribe to member events (see above), otherwise I do not know, is this effectively the same or not?
Thunk function (the second argument of runOn method)? What is that? How can use it?

Dynamic properties in Scala

Does Scala support something like dynamic properties? Example:
val dog = new Dynamic // Dynamic does not define 'name' nor 'speak'.
dog.name = "Rex" // New property.
dog.speak = { "woof" } // New method.
val cat = new Dynamic
cat.name = "Fluffy"
cat.speak = { "meow" }
val rock = new Dynamic
rock.name = "Topaz"
// rock doesn't speak.
def test(val animal: Any) = {
animal.name + " is telling " + animal.speak()
}
test(dog) // "Rex is telling woof"
test(cat) // "Fluffy is telling meow"
test(rock) // "Topaz is telling null"
What is the closest thing from it we can get in Scala? If there's something like "addProperty" which allows using the added property like an ordinary field, it would be sufficient.
I'm not interested in structural type declarations ("type safe duck typing"). What I really need is to add new properties and methods at runtime, so that the object can be used by a method/code that expects the added elements to exist.
Scala 2.9 will have a specially handled Dynamic trait that may be what you are looking for.
This blog has a big about it: http://squirrelsewer.blogspot.com/2011/02/scalas-upcoming-dynamic-capabilities.html
I would guess that in the invokeDynamic method you will need to check for "name_=", "speak_=", "name" and "speak", and you could store values in a private map.
I can not think of a reason to really need to add/create methods/properties dynamically at run-time unless dynamic identifiers are also allowed -and/or- a magical binding to an external dynamic source (JRuby or JSON are two good examples).
Otherwise the example posted can be implemented entirely using the existing static typing in Scala via "anonymous" types and structural typing. Anyway, not saying that "dynamic" wouldn't be convenient (and as 0__ pointed out, is coming -- feel free to "go edge" ;-).
Consider:
val dog = new {
val name = "Rex"
def speak = { "woof" }
}
val cat = new {
val name = "Fluffy"
def speak = { "meow" }
}
// Rock not shown here -- because it doesn't speak it won't compile
// with the following unless it stubs in. In both cases it's an error:
// the issue is when/where the error occurs.
def test(animal: { val name: String; def speak: String }) = {
animal.name + " is telling " + animal.speak
}
// However, we can take in the more general type { val name: String } and try to
// invoke the possibly non-existent property, albeit in a hackish sort of way.
// Unfortunately pattern matching does not work with structural types AFAIK :(
val rock = new {
val name = "Topaz"
}
def test2(animal: { val name: String }) = {
animal.name + " is telling " + (try {
animal.asInstanceOf[{ def speak: String }).speak
} catch { case _ => "{very silently}" })
}
test(dog)
test(cat)
// test(rock) -- no! will not compile (a good thing)
test2(dog)
test2(cat)
test2(rock)
However, this method can quickly get cumbersome (to "add" a new attribute one would need to create a new type and copy over the current data into it) and is partially exploiting the simplicity of the example code. That is, it's not practically possible to create true "open" objects this way; in the case for "open" data a Map of sorts is likely a better/feasible approach in the current Scala (2.8) implementation.
Happy coding.
First off, as #pst pointed out, your example can be entirely implemented using static typing, it doesn't require dynamic typing.
Secondly, if you want to program in a dynamically typed language, program in a dynamically typed language.
That being said, you can actually do something like that in Scala. Here is a simplistic example:
class Dict[V](args: (String, V)*) extends Dynamic {
import scala.collection.mutable.Map
private val backingStore = Map[String, V](args:_*)
def typed[T] = throw new UnsupportedOperationException()
def applyDynamic(name: String)(args: Any*) = {
val k = if (name.endsWith("_=")) name.dropRight(2) else name
if (name.endsWith("_=")) backingStore(k) = args.first.asInstanceOf[V]
backingStore.get(k)
}
override def toString() = "Dict(" + backingStore.mkString(", ") + ")"
}
object Dict {
def apply[V](args: (String, V)*) = new Dict(args:_*)
}
val t1 = Dict[Any]()
t1.bar_=("quux")
val t2 = new Dict("foo" -> "bar", "baz" -> "quux")
val t3 = Dict("foo" -> "bar", "baz" -> "quux")
t1.bar // => Some(quux)
t2.baz // => Some(quux)
t3.baz // => Some(quux)
As you can see, you were pretty close, actually. Your main mistake was that Dynamic is a trait, not a class, so you can't instantiate it, you have to mix it in. And you obviously have to actually define what you want it to do, i.e. implement typed and applyDynamic.
If you want your example to work, there are a couple of complications. In particular, you need something like a type-safe heterogenous map as a backing store. Also, there are some syntactic considerations. For example, foo.bar = baz is only translated into foo.bar_=(baz) if foo.bar_= exists, which it doesn't, because foo is a Dynamic object.

Reflection on a Scala case class

I'm trying to write a trait (in Scala 2.8) that can be mixed in to a case class, allowing its fields to be inspected at runtime, for a particular debugging purpose. I want to get them back in the order that they were declared in the source file, and I'd like to omit any other fields inside the case class. For example:
trait CaseClassReflector extends Product {
def getFields: List[(String, Any)] = {
var fieldValueToName: Map[Any, String] = Map()
for (field <- getClass.getDeclaredFields) {
field.setAccessible(true)
fieldValueToName += (field.get(this) -> field.getName)
}
productIterator.toList map { value => fieldValueToName(value) -> value }
}
}
case class Colour(red: Int, green: Int, blue: Int) extends CaseClassReflector {
val other: Int = 42
}
scala> val c = Colour(234, 123, 23)
c: Colour = Colour(234,123,23)
scala> val fields = c.getFields
fields: List[(String, Any)] = List((red,234), (green,123), (blue,23))
The above implementation is clearly flawed because it guesses the relationship between a field's position in the Product and its name by equality of the value on those field, so that the following, say, will not work:
Colour(0, 0, 0).getFields
Is there any way this can be implemented?
Look in trunk and you'll find this. Listen to the comment, this is not supported: but since I also needed those names...
/** private[scala] so nobody gets the idea this is a supported interface.
*/
private[scala] def caseParamNames(path: String): Option[List[String]] = {
val (outer, inner) = (path indexOf '$') match {
case -1 => (path, "")
case x => (path take x, path drop (x + 1))
}
for {
clazz <- getSystemLoader.tryToLoadClass[AnyRef](outer)
ssig <- ScalaSigParser.parse(clazz)
}
yield {
val f: PartialFunction[Symbol, List[String]] =
if (inner.isEmpty) {
case x: MethodSymbol if x.isCaseAccessor && (x.name endsWith " ") => List(x.name dropRight 1)
}
else {
case x: ClassSymbol if x.name == inner =>
val xs = x.children filter (child => child.isCaseAccessor && (child.name endsWith " "))
xs.toList map (_.name dropRight 1)
}
(ssig.symbols partialMap f).flatten toList
}
}
Here's a short and working version, based on the example above
trait CaseClassReflector extends Product {
def getFields = getClass.getDeclaredFields.map(field => {
field setAccessible true
field.getName -> field.get(this)
})
}
In every example I've seen the fields are in reverse order: the last item in the getFields array is the first one listed in the case class. If you use case classes "nicely", then you should just be able to map productElement(n) onto getDeclaredFields()( getDeclaredFields.length-n-1).
But this is rather dangerous, as I don't know of anything in the spec that insists that it must be that way, and if you override a val in the case class, it won't even appear in getDeclaredFields (it'll appear in the fields of that superclass).
You might change your code to assume things are this way, but check that the getter method with that name and the productIterator return the same value and throw an exception if they don't (which means that you don't actually know what corresponds to what).
You can also use the ProductCompletion from the interpreter package to get to attribute names and values of case classes:
import tools.nsc.interpreter.ProductCompletion
// get attribute names
new ProductCompletion(Colour(1, 2, 3)).caseNames
// returns: List(red, green, blue)
// get attribute values
new ProductCompletion(Colour(1, 2, 3)).caseFields
Edit: hints by roland and virtualeyes
It is necessary to include the scalap library which is part of the scala-lang collection.
Thanks for your hints, roland and virtualeyes.

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