[
https://issues.apache.org/jira/browse/S2GRAPH-229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16529452#comment-16529452
]
ASF GitHub Bot commented on S2GRAPH-229:
----------------------------------------
GitHub user daewon opened a pull request:
https://github.com/apache/incubator-s2graph/pull/178
[S2GRAPH-229] 'Step' abstraction for combinable queries
# Step interface abstraction for combinable queries.
I have created an interface for each step to enable query
combinations(using Observable[T])
```scala
trait RxStep[-A, +B] extends (A => Observable[B])
```
RxStep simply inherits the function interface (A => B)
This makes it possible to naturally connect with the transform functions
provided by Observable (map, flatMap ..)
I have implemented a simple query in the `GraphTest.scala` file for the
step utilization test.
Here is the example code.
'VertexFetchStep' and 'EdgeFetchStep' each implement RxStep trait.
In addition, since GraphElement => Boolean is implemented in 'Where', it
naturally integrates with Observable interface.
```scala
val v1 = VertexFetchStep(graph)
val qpIn = QueryParam(labelName = testLabelName, direction = "in")
val qpOut = QueryParam(labelName = testLabelName, direction = "out")
val e1 = EdgeFetchStep(graph, qpIn)
val e2 = EdgeFetchStep(graph, qpOut)
val where = Where("_to = 20").get
val q =
v1.apply(vertices)
.flatMap(e1)
.filter(where.filter)
.map(_.tgtForVertex)
.flatMap(v => e1.apply(v) ++ e2.apply(v))
val res = q.toBlocking.toList
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/daewon/incubator-s2graph S2GRAPH-229
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-s2graph/pull/178.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #178
----
commit 6b088944b877b25775ac424658ad9b6472203082
Author: daewon <daewon@...>
Date: 2018-07-02T06:28:17Z
make step works
----
> 'Step' abstraction for combinable queries
> -----------------------------------------
>
> Key: S2GRAPH-229
> URL: https://issues.apache.org/jira/browse/S2GRAPH-229
> Project: S2Graph
> Issue Type: Task
> Components: s2core
> Reporter: Daewon Jeong
> Priority: Minor
>
> Graph Query is a combination of queries of each step.
> For example,
> 1. you can take a vertex,
> 2. then bring the edge back with that vertex,
> 3. get the vertex from the edge,
> 4. and bring the edge from that vertex.
> The query that is being provided now is not tied to each of the above steps,
> but is tightly coupled throughout the query.
> Since functions such as filter, transform(group_by, merge), and
> postprocess(conversion to json/xml) are tightly coupled to the entire query
> function,
> it is difficult to test each function separately.
> To solve this problem,
> 1. each step is created as an independent function and
> 2. the function of assembling each step is separated separately.
> Each step is separated as above, the following functions can be implemented
> without additional code.
> ex) In the case of deleteAll, fetch each edge and make delete request
> again.
> Implement Prototyping
> 1. For query efficiency, each step implements the function to return
> Observable.
> 2. Use Observable(RxScala)'s flatMap to connect each step.
> Below is the pseudocode.
> 1. Bringing the edges from the vertex, collect only edges whose score is 0.5
> and serialize them to Json
> {code:java}
> val vs: Step[Int, S2VertexLike] = VertexStep()
> val es: Step[S2VertexLike, S2EdgeLike] = EdgeStep(dir = "OUT")
> val js: Step[S2EdgeLike, Json] = JsonSerializeStep(limit: 10)
> val q: Observable[Json] =
> vs.apply(1)
> .flatMap(es)
> .filter(_.property("score") > 0.5)
> .flatMap(js)
> {code}
> What to think about.
> 1. The ability to link each step is subject to Observable.
> - This makes it impossible to draw the connection graph of the Step instead
> of making the function easier to implement.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
