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DATAMONGO-1880 - Polishing.

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Turn instance methods into static ones where applicable. Avoid parameter type array cloning where possible.
Add reference to rework stack-trace inspection in order to throw ClientSessionException. Migrate MongoPersistentEntityIndexCreatorUnitTests to AssertJ. Add tests to verify simple session proxy wrapping on subsequent MongoDbFactory.withSession(…) calls.

Guard ClientSession tests with replica set rule. Remove unused code. Add non-null guards. Add missing Nullable annotations. Slightly tweak Javadoc and reference documentation.

Original pull request: #536.
This commit is contained in:
Mark Paluch
2018-03-19 11:42:56 +01:00
parent b9f7f23b8f
commit 91717e5566
28 changed files with 315 additions and 201 deletions
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20
src/main/asciidoc/reference/client-session.adoc
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@@ -5,11 +5,11 @@ As of version 3.6 MongoDB supports a concept of Sessions. The use of sessions en
WARNING: Operations within a client session are not isolated from operations outside the session.
Both `MongoOperations` and `ReactiveMongoOperations` provide gateway methods for tying a `ClientSession` to the operations themselves. Within the callback all operations on `MongoCollection` and `MongoDatabase` are called with the provided session via a `Proxy` without the need to add it manually. This means that a potential call to `MongoCollection#find()` is delegated to `MongoCollection#find(ClientSession)`.
Both `MongoOperations` and `ReactiveMongoOperations` provide gateway methods for tying a `ClientSession` to the operations themselves. `MongoCollection` and `MongoDatabase` use session proxy objects implementing MongoDB's collection and and database interfaces so there's no need to add a session on each call. This means that a potential call to `MongoCollection#find()` is delegated to `MongoCollection#find(ClientSession)`.
NOTE: Methods like `(Reactive)MongoOperations#getCollection` returning native MongoDB java driver gateway objects, such as `MongoCollection`, that themselves offer dedicated methods for `ClientSession` will *NOT* be wrapped by the `Proxy`. So please make sure to provide the `ClientSession` where needed when interacting directly with a `MongoCollection` or `MongoDatabase` and not via one of the `#excute` callbacks on `MongoOperations`.
NOTE: Methods like `(Reactive)MongoOperations#getCollection` returning native MongoDB Java Driver gateway objects, such as `MongoCollection`, that themselves offer dedicated methods for `ClientSession` are *NOT* be session-proxied. So make sure to provide the `ClientSession` where needed when interacting directly with a `MongoCollection` or `MongoDatabase` and not via one of the `#execute` callbacks on `MongoOperations`.
.ClientSession with MongoOperations.
.ClientSession with `MongoOperations`
====
[source,java]
----
@@ -37,14 +37,14 @@ session.close() <4>
----
<1> Obtain a new session from the server.
<2> Use `MongoOperation` methods as before. The `ClientSession` gets applied automatically.
<3> Important! Do not forget to close the session.
<3> Make sure to close the `ClientSession`.
====
WARNING: When dealing with ``DBRef``s, especially lazily loaded ones, it is essential to **not** close the `ClientSession` before all data is loaded.
WARNING: When dealing with ``DBRef``s, especially lazily loaded ones, it is essential to **not** close the `ClientSession` before all data is loaded. Otherwise, lazy fetch fails.
The reactive counterpart uses the very same building blocks as the imperative one.
.ClientSession with ReactiveMongoOperations.
.ClientSession with `ReactiveMongoOperations`
====
[source,java]
----
@@ -66,14 +66,14 @@ template.withSession(session)
return action.insert(azoth); <2>
});
}, ClientSession::close) <4>
}, ClientSession::close) <3>
.subscribe();
----
<1> Obtain a `Publisher` for new session retrieval.
<2> Use `MongoOperation` methods as before. The `ClientSession` is obtained and applied automatically.
<3> Important! Do not forget to close the session.
<2> Use `ReactiveMongoOperation` methods as before. The `ClientSession` is obtained and applied automatically.
<3> Make sure to close the `ClientSession`.
====
By using a `Publisher` providing the actual session you can defer session acquisition to the point of actual subscription.
Still you need to close the session when done in order to not pollute the server with stale sessions. Use the `doFinally` hook on `execute` to call `ClientSession#close()` when you don't need the session any more.
In case you prefer having more control over the session itself, you can always obtain the `ClientSession` via the driver and provide it via a `Supplier`.
In case you prefer having more control over the session itself, you can always obtain the `ClientSession` via the driver and provide it via a `Supplier`.