Develop Reference

recognize parameter change from git repository

I want to extract signature changes (method parameter changes to be exact) from commits to git repository by a java program. I have used the following code:
for (Ref branch : branches) {
String branchName = branch.getName();
for (RevCommit commit : commits) {
boolean foundInThisBranch = false;
RevCommit targetCommit = walk.parseCommit(repo.resolve(
commit.getName()));
for (Map.Entry<String, Ref> e : repo.getAllRefs().entrySet()) {
if (e.getKey().startsWith(Constants.R_HEADS)) {
if (walk.isMergedInto(targetCommit, walk.parseCommit(
e.getValue().getObjectId()))) {
String foundInBranch = e.getValue().getName();
if (branchName.equals(foundInBranch)) {
foundInThisBranch = true;
break;
}
}
}
}
I can extract commit message, commit data and Author name from that, however, I am not able to extract parameter changes from them. I mean it is unable for me to identify parameter changes. I want to know if there is any way to recognize that. I mean it is impossible to recognize them from commit notes that are generated by programmers; I am looking for something like any specific annotation or something else.
This is my code to extract differences:
CanonicalTreeParser oldTreeIter = new CanonicalTreeParser();
oldTreeIter.reset(reader, oldId);
CanonicalTreeParser newTreeIter = new CanonicalTreeParser();
newTreeIter.reset(reader, headId);
List<DiffEntry> diffs= git.diff()
.setNewTree(newTreeIter)
.setOldTree(oldTreeIter)
.call();
ByteArrayOutputStream out = new ByteArrayOutputStream();
DiffFormatter df = new DiffFormatter(out);
df.setRepository(git.getRepository());
The export is really huge and impossible to extract method changes.

You show a way you've found to examine the diffs, but say that the output is too large and you can't extract the method signature changes. If by that you mean that you're asking about specific git support for telling you that a method signature changes, then no - no such support exists. This is because git does not "know" anything about the languages you may or may not have used in the files under source control. Everything is just content that is, or is not, different from other content.
Since a method signature could be split across lines in any number of ways, it's not even guaranteed that just because a method's signature changed its name would appear anywhere in the diff. What you would really have to do is perform a sort of "structural diff". That is, you would have to
check out the "old" version, and pass it to a java parser
check out the "new" version, and pass it to a java parser
compare the resulting parse trees, looking for methods that belong to the same object, but have changed
Even that won't be terribly easy, because methods could be renamed, and because method overloading could make it unclear which signature change goes with which version of a method.
From there what you have is a non-trivial coding problem, which is beyond the scope of SO to answer. If you decide to tackle this problem and run into specific programming questions along the way, of course you could post those questions and perhaps someone will be able to help.

Enumerate Custom Slot Values from Speechlet

Is there any way to inspect or enumerate the Custom Slot Values that are set-up in your interaction model? For Instance, Say you have an intent schema with the following intent:
{
"intent": "MySuperCoolIntent",
"slots":
[
{
"name": "ShapesNSuch",
"type": "LIST_OF_SHAPES"
}
]
}
Furthermore, you've defined the LIST_OF_SHAPES Custom Slot to have the following Values:
SQUARE
TRIANGLE
CIRCLE
ICOSADECAHECKASPECKAHEDRON
ROUND
HUSKY
Question: is there a method I can call from my Speechlet or my RequestStreamHandler that will give me an enumeration of those Custom Slot Values??
I have looked through the Alexa Skills Kit's SDK Javadocs Located Here
And I'm not finding anything.
I know I can get the Slot's value that is sent in with the intent:
String slotValue = incomingIntentRequest.getIntent().getSlot("LIST_OF_SHAPES").getValue();
I can even enumerate ALL the incoming Slots (and with it their values):
Map<String, Slot> slotMap = IncomingIntentRequest.getIntent().getSlots();
for(Map.Entry<String, Slot> entry : slotMap.entrySet())
{
String key = entry.getKey();
Slot slot = (Slot)entry.getValue();
String slotName = slot.getName();
String slotValue = slot.getValue();
//do something nifty with the current slot info....
}
What I would really like is something like:
String myAppId = "amzn1.echo-sdk-ams.app.<TheRestOfMyID>";
List<String> posibleSlotValues = SomeMagicAlexaAPI.getAllSlotValues(myAppId, "LIST_OF_SHAPES");
With this information I wouldn't have to maintain two separate "Lists" or "Enumerations"; One within the interaction Model and another one within my Request Handler. Seems like this should be a thing right?

No, the API does not allow you to do this.
However, since your interaction model is intimately tied with your development, I would suggest you check in the model with your source code in your source control system. If you are going to do that, you might as well put it with your source. Depending on your language, that also means you can probably read it during run-time.
Using this technique, you can gain access to your interaction model at run-time. Instead of doing it automatically through an API, you do it by best practice.
You can see several examples of this in action for Java in TsaTsaTzu's examples.

No - there is nothing in the API that allows you to do that.
You can see the full extent of the Request Body structure Alexa gives you to work with. It is very simple and available here:
https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/alexa-skills-kit-interface-reference#Request%20Format
Please note, the Request Body is not to be confused with the request, which is a structure in the request body, with two siblings: version and session.

Google App Engine Objectify - load single objects or list of keys?

I am trying to get a grasp on Google App Engine programming and wonder what the difference between these two methods is - if there even is a practical difference.
Method A)
public Collection<Conference> getConferencesToAttend(Profile profile)
{
List<String> keyStringsToAttend = profile.getConferenceKeysToAttend();
List<Conference> conferences = new ArrayList<Conference>();
for(String conferenceString : keyStringsToAttend)
{
conferences.add(ofy().load().key(Key.create(Conference.class,conferenceString)).now());
}
return conferences;
}
Method B)
public Collection<Conference> getConferencesToAttend(Profile profile)
List<String> keyStringsToAttend = profile.getConferenceKeysToAttend();
List<Key<Conference>> keysToAttend = new ArrayList<>();
for (String keyString : keyStringsToAttend) {
keysToAttend.add(Key.<Conference>create(keyString));
}
return ofy().load().keys(keysToAttend).values();
}
the "conferenceKeysToAttend" list is guaranteed to only have unique Conferences - does it even matter then which of the two alternatives I choose? And if so, why?

Method A loads entities one by one while method B does a bulk load, which is cheaper, since you're making just 1 network roundtrip to Google's datacenter. You can observe this by measuring time taken by both methods while loading a bunch of keys multiple times.
While doing a bulk load, you need to be cautious about loaded entities, if datastore operation throws exception. Operation might succeed even when some of the entities are not loaded.

The answer depends on the size of the list. If we are talking about hundreds or more, you should not make a single batch. I couldn't find documentation what is the limit, but there is a limit. If it not that much, definitely go with loading one by one. But, you should make the calls asynchronous by not using the now function:
List<<Key<Conference>> conferences = new ArrayList<Key<Conference>>();
conferences.add(ofy().load().key(Key.create(Conference.class,conferenceString));
And when you need the actual data:
for (Key<Conference> keyConference : conferences ) {
Conference c = keyConference.get();
......
}

Neo4j - How to handle incompatible RestGraphDatabase calls

In my project I'm using Neo4j's Core-API through GraphDatabaseService. In Tests we have an EmbeddedGraphDatabase where everything works as expected. I then wrote some tests to see how my implementation behaves on a RestGraphDatabase, just to find out, that most of it fails!
(The GraphDatabaseService is obtained by GraphDatabaseFactory of the Rest-API, so without an instanceof check I do not know which one it is)
Some examples:
If I use GlobalGraphOperations everything will fail, because GlopalGraphOperations are not supported by the RestGraphDatabase. (Strange enough that GlobalGraphOperations.at doesn't throw but all methods from GlobalGraphOperations).
Then I thought "ok I'll use Cypher to get the same behavior."
I tryed to implement a Method like this:
public getNodesWithLabel(String label, GraphDatabaseService graphService){
try(Transaction tx graphService.beginTx()){
ExecutionEngine ee = new ExecutionEngine(graphService);
//throws NullPOinterExeption in execute method
ExecutionResult result = ee.execute("MATCH (n:" + label + ") RETURN n");
result.columnAs("n");
//... mapping of Nodes
}
}
Searching through the API I see, that there is a RestCypherQueryEngine which is initialized via a RestAPIFascade. Problem here is, that the methods are not interchangeable, do not implement the same interface, and the return types are completeley different (i.e. ExecutionResult vs QueryResult)
So my question is: Is there a way, to get the same behavior from Neo4j where the used technology (Rest vs. Embedded) doesn't matter? Some kind of a technology independed Wrapper will suit my needs.
by the way, I'm using Neo4j in Version 2

Just don't do it. What it would do (if it worked) would be to execute every call to the database over the wire, ever read and write of nodes, rels and properties. You don't want to do that.
Use this instead.
queryEngine = new RestCypherQueryEngine(restGraphDb.getRestAPI());
queryEngine.query(query, params)
This sends the queries to the server and runs them there.

Compare two source code files using EMF models

In my application I should compare two source code files to see if something has changed and then highlight those changes. For that i thought of using EMF compare. My application is a standalone application and is not used as a plugin or something similar. It should run without eclipse. Therefore I linked all the necessary libraries and tried to use EMF compare.
The problem now is that I don´t know how to build the two models that I have to use to compare the two source code files against each other. In the following code snippet I wrote as a first approach, the source code files are passed as files (Test1.java and Test2.java) but actually the source code of both files are stored in a string as the method parameters indicate.
So my question is basically how can I generate two models based on String that contain Java source code so that I can use these two models to compare against each other?
public void compare(String source1, String source2) throws IOException, InterruptedException {
Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().put("java", new ResourceFactoryImpl());
XSDEcoreBuilder builder = new XSDEcoreBuilder();
Collection<EObject> model1 = builder.generate(URI.createFileURI("Test1.java"));
Collection<EObject> model2 = builder.generate(URI.createFileURI("Test2.java"));
final MatchModel match = MatchService.doMatch(model1.iterator().next(), model2.iterator().next(), Collections.<String, Object> emptyMap());
final DiffModel diff = DiffService.doDiff(match, false);
final List<DiffElement> differences = new ArrayList<DiffElement>(diff.getOwnedElements());
System.out.println("MatchModel :\n");
System.out.println(ModelUtils.serialize(match));
System.out.println("DiffModel :\n");
System.out.println(ModelUtils.serialize(diff));
}

You can use Java metamodel from Modisco project, I think.
With it you can deserialize java files into EMF model and then compare.
EMFText project also has Java model implementation.
Give 'em a try!

I think you are using the wrong technology here. AFAIK, EMF doesn't support a parser generator that you could use to parse Java source code and build parse trees as EMF models.
IMO, a better idea would be to use one of the existing Java parser generators (ANTLR, JavaCC, etc) and an existing Java grammar, then implement your comparison based on the parse trees that the generated parser produces.