Connection issues cannot be distinguished from document missing

[tperamaki]

In ArangoCollection.java both the documentExists(key) or the getDocument(key, type) consume the errors, which makes it impossible to know if the document actually did not exist, or if there was a connection issue and we should try again later when the connectivity has been restored.

For example arangoDB.db("database").collection("collection").documentExists("document") returns true if the document exists, but false for everything else, which includes document does not exist, database does not exist, collection does not exist, and any connection issues.

[mvollmary]

@tperamaki Hi, thanks for reporting.

[mvollmary]

@tperamaki I saw your PR a little to late :-(

[mvollmary]

@tperamaki I took a closer look into your solution. I think - especially with documentExists - some people will run into trouble because it isn't compatible any more.

I added a field in DocumentExistsOptions and DocumentReadOptions where you can define whether the exception should be catched or not.

[tperamaki]

Took a quick look into your commit, and I was wondering that shouldn't it still be returning false / null for cases where the error code is 404, as that basically means that everything went fine, but the document was not found?

[mvollmary]

good point. I will add a check on the response code like in your commit.

Thanks again