Updated Getting Started tutorial with new addE(label) syntax CTR
Project: http://git-wip-us.apache.org/repos/asf/tinkerpop/repo Commit: http://git-wip-us.apache.org/repos/asf/tinkerpop/commit/19825973 Tree: http://git-wip-us.apache.org/repos/asf/tinkerpop/tree/19825973 Diff: http://git-wip-us.apache.org/repos/asf/tinkerpop/diff/19825973 Branch: refs/heads/master Commit: 1982597343e1882681db355e038667d44a77d7ef Parents: 073f452 Author: Stephen Mallette <sp...@genoprime.com> Authored: Thu Aug 10 13:34:11 2017 -0400 Committer: Stephen Mallette <sp...@genoprime.com> Committed: Thu Aug 10 13:34:11 2017 -0400 ---------------------------------------------------------------------- .../tutorials/getting-started/index.asciidoc | 33 +++++++++++++------- 1 file changed, 21 insertions(+), 12 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/tinkerpop/blob/19825973/docs/src/tutorials/getting-started/index.asciidoc ---------------------------------------------------------------------- diff --git a/docs/src/tutorials/getting-started/index.asciidoc b/docs/src/tutorials/getting-started/index.asciidoc index 84e128a..ef6e7ed 100644 --- a/docs/src/tutorials/getting-started/index.asciidoc +++ b/docs/src/tutorials/getting-started/index.asciidoc @@ -203,24 +203,26 @@ as an example. First, you need to create this graph: [gremlin-groovy] ---- graph = TinkerGraph.open() -v1 = graph.addVertex(id, 1, label, "person", "name", "marko", "age", 29) -v2 = graph.addVertex(id, 3, label, "software", "name", "lop", "lang", "java") -v1.addEdge("created", v2, id, 9, "weight", 0.4) +g = graph.traversal() +v1 = g.addV("person").property(id, 1).property("name", "marko").property("age", 29).next() +v2 = g.addV("person").property(id, 3).property("name", "lop").property("lang", "java").next() +g.addE("created").from(v1).to(v2).property(id, 9).property("weight", 0.4) ---- -There are a number of important things to consider in the above code. First, recall that `id` and `label` are +There are a number of important things to consider in the above code. First, recall that `id` is "reserved" for special usage in TinkerPop and are members of the enum, `T`. Those "keys" supplied to the creation method are link:https://docs.oracle.com/javase/8/docs/technotes/guides/language/static-import.html[statically imported] to the console, which allows you to access them without having to specify their owning enum. Think of it as a -shorthand form that enables a more fluid code style. You would normally refer to them as `T.id` and `T.label`. Without +shorthand form that enables a more fluid code style. You would normally refer to it as `T.id`. Without that static importing you would instead have to write: [gremlin-groovy] ---- graph = TinkerGraph.open() -v1 = graph.addVertex(T.id, 1, T.label, "person", "name", "marko", "age", 29) -v2 = graph.addVertex(T.id, 3, T.label, "software", "name", "lop", "lang", "java") -v1.addEdge("created", v2, id, 9, "weight", 0.4) +g = graph.traversal() +v1 = g.addV("person").property(T.id, 1).property("name", "marko").property("age", 29).next() +v2 = g.addV("person").property(T.id, 3).property("name", "lop").property("lang", "java").next() +g.addE("created").from(v1).to(v2).property(T.id, 9).property("weight", 0.4) ---- NOTE: The fully qualified name for `T` is `org.apache.tinkerpop.gremlin.structure.T`. Another important static import @@ -510,20 +512,27 @@ graph.createIndex('userId', Vertex.class) <1> g = graph.traversal() getOrCreate = { id -> - g.V().has('userId', id).tryNext().orElseGet{ g.addV().property('userId', id).next() } + g.V().has('userId', id). + fold(). + coalesce(unfold(), + addV('user').property('userId', id)).next() <2> } new File('wiki-Vote.txt').eachLine { if (!it.startsWith("#")){ - (fromVertex, toVertex) = it.split('\t').collect(getOrCreate) <2> - fromVertex.addEdge('votesFor', toVertex) + (fromVertex, toVertex) = it.split('\t').collect(getOrCreate) <3> + g.addE('votesFor').from(fromVertex).to(toVertex).iterate() } } ---- <1> To ensure fast lookups of vertices, we need an index. The `createIndex()` method is a method native to TinkerGraph. Please consult your graph databases documentation for their index creation approaches. -<2> We are iterating each line of the `wiki-Vote.txt` file and this line splits the line on the delimiter, then +<2> This "get or create" traversal gets a a vertex if it already exists and if not creates it. It uses `coalesce()` in +a clever way by first determining if the list of vertices produced by the previous `fold()` has anything in it by +testing the result of `unfold()`. If `unfold()` returns nothing then that vertex doesn't exist and the subsequent +`addV()` inner traversal can be called to create it. +<3> We are iterating each line of the `wiki-Vote.txt` file and this line splits the line on the delimiter, then uses some neat Groovy syntax to apply the `getOrCreate()` function to each of the two `userId` fields encountered in the line and stores those vertices in the `fromVertex` and `toVertex` variables respectively.
