[Gremlin] The Generalize AsPipe model - back(), loop(), and table()

[Marko Rodriguez]

Hi people,

The 'as' pipe/step has come to be very handy. You can now use as() to name a step and it will work (naturally) for back(), loop(), and table().

Here are some examples over the graph defined here: 

https://github.com/tinkerpop/gremlin/wiki/defining-a-property-graph

*** BACK ***

gremlin> g.v(1).out('knows').as('x').filter{it.name.equals('josh')}.back('x')

==>v[4]

gremlin> g.v(1).out('knows').as('x').filter{it.name.equals('josh')}.back('x').name

==>josh

https://github.com/tinkerpop/gremlin/wiki/Backtrack-Pattern

*** LOOP ***

gremlin> g.v(1).as('x').outE.inV.loop('x'){it.loops < 2}

==>v[2]

==>v[3]

==>v[4]

(NOTE: see how as('x').....loop('x') naturally wrap the loop point)

https://github.com/tinkerpop/gremlin/wiki/Loop-Pattern

*** TABLE ***

gremlin> t = new Table()

gremlin> g.v(1).as('x').out.as('y').table(t)

==>v[2]

==>v[3]

==>v[4]

gremlin> t

==>[x:v[1], y:v[2]]

==>[x:v[1], y:v[3]]

==>[x:v[1], y:v[4]]

https://github.com/tinkerpop/gremlin/wiki/Pattern-Match-Pattern

This is definitely a solid model and it has a natural mapping to the underling Pipes engine. Feel free to toString() a pipeline to see how it gets compiled.

Enjoy!,

Marko.

P.S. This is in GitHub and in TinkerPop Maven2 repository.

http://markorodriguez.com

[Pierre De Wilde]

Intuitive since it works (now) as expected.

Thanks, Marko.

Pierre

2011/6/11 Marko Rodriguez <okram...@gmail.com>

[Marko Rodriguez]

Thanks for the support Pierre.

I'm really pumped up about 'as'. I couldn't wait to wake up and play with it this morning :).

g.v(89).as('x').out.as('y').name.groupCount(m).back('y').loop('x'){c++ < 100}

...here is the toString():

[AsPipe(x)[IdentityPipe], LoopPipe[[AsPipe(y)[OutPipe], BackFilterPipe[[PropertyPipe(name), GroupCountClosurePipe]]]]]

 

Sexy :).

The old 'as' model I was playing with was super convoluted and not programmically pretty -- I was being dumb about it. The new AsPipe solution was the key. AsPipe implements MetaPipe (a pipe that wraps another pipe -- simply has a getPipes() method). Other MetaPipes include LoopPipe, BackFilterPipe, Pipeline, AsPipe, AndPipe, OrPipe, SplitPipe, MergePipe. I'm sure we will find more uses into the future.......

Finally, check this out. With the way 'as' works, you can do recursive pattern matching --- a very attractive proposition.

gremlin> g.v(89).as('x').out.as('y').name.groupCount(m).back('y').loop('x'){c++ < 100}.name.as('z').table(t)

...

gremlin> t ==>[x:v[89], y:v[83], z:EYES OF THE WORLD] ==>[x:v[89], y:v[21], z:TRUCKING] ==>[x:v[89], y:v[206], z:SING ME BACK HOME] ==>[x:v[89], y:v[127], z:MORNING DEW] ==>[x:v[89], y:v[49], z:HES GONE] ==>[x:v[89], y:v[129], z:CHINA DOLL] ==>[x:v[89], y:v[149], z:SPANISH JAM] ==>[x:v[89], y:v[148], z:THE OTHER ONE] ==>[x:v[89], y:v[130], z:WHARF RAT] ==>[x:v[89], y:v[339], z:Hunter] ==>[x:v[89], y:v[340], z:Garcia] ==>[x:v[89], y:v[296], z:MIND LEFT BODY JAM]

...

..

.

Finally, see out: https://github.com/tinkerpop/gremlin/wiki/Pattern-Match-Pattern (have the new 2nd section. Check out t.apply{} :)

See ya,

Marko.

http://markorodriguez.com

[Pierre De Wilde]

Awesome.

Here is a way to convert a graph into simple triples:

gremlin> g.V.name.as('s').back(1).outE.label.as('p').back(1).inV.name.as('o').back(1).table(t)

...

gremlin> t

==>[s:marko, p:knows, o:vadas]

==>[s:marko, p:created, o:lop]

==>[s:marko, p:knows, o:josh]

==>[s:peter, p:created, o:lop]

==>[s:josh, p:created, o:ripple]

==>[s:josh, p:created, o:lop]

Pierre

[Pierre De Wilde]

Unfortunately, there is a known issue that prevent Rexster to play with us:

http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g.V.name.as('s').back(1).outE.label.as('p').back(1).inV.name.as('o').back(1).table(t);t

{"results":[],"success":true,"version":"0.4-SNAPSHOT","queryTime":5.304064}

http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g.V.name.as('s').back(1).outE.label.as('p').back(1).inV.name.as('o').back(1).table(t)

{"results":[{"_id":"2","_type":"vertex","name":"vadas","age":27},{"_id":"3","_type":"vertex","name":"lop","lang":"java"},{"_id":"4","_type":"vertex","name":"josh","age":32},{"_id":"3","_type":"vertex","name":"lop","lang":"java"},{"_id":"5","_type":"vertex","name":"ripple","lang":"java"},{"_id":"3","_type":"vertex","name":"lop","lang":"java"}],"success":true,"version":"0.4-SNAPSHOT","queryTime":124.003072}

Hope that Stephen may solve this issue.

Thanks,

Pierre

2011/6/11 Pierre De Wilde <pierre...@gmail.com>

[Marko Rodriguez]

Thats cool.

One could create a Table->RDF converter.

Marko.

http://markorodriguez.com

[stephen mallette]

Pierre, looks like the world is going to have to wait a little longer
on this fix. I took a stab at fixing it today:

https://github.com/tinkerpop/rexster/issues/110

sadly, I couldn't solve it. Marko, I assume that you got email
notification of my shame in not being able to solve this one. Please
take a look when you get a chance. Thanks.

On Jun 11, 1:08 pm, Pierre De Wilde <pierredewi...@gmail.com> wrote:
> Unfortunately, there is a known issue that prevent Rexster to play with us:
>

> http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g...
> <http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g...>

> {"results":[],"success":true,"version":"0.4-SNAPSHOT","queryTime":5.304064}
>

> http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g...)
> <http://localhost:8182/tinkergraph/tp/gremlin?script=t=new%20Table();g...)>
> {"results":[{"_id":"2","_type":"vertex","name":"vadas","age":27},{"_id":"3" ,"_type":"vertex","name":"lop","lang":"java"},{"_id":"4","_type":"vertex"," name":"josh","age":32},{"_id":"3","_type":"vertex","name":"lop","lang":"jav a"},{"_id":"5","_type":"vertex","name":"ripple","lang":"java"},{"_id":"3"," _type":"vertex","name":"lop","lang":"java"}],"success":true,"version":"0.4- SNAPSHOT","queryTime":124.003072}

>
> Hope that Stephen may solve this issue.
>
> Thanks,
>
> Pierre
>

> 2011/6/11 Pierre De Wilde <pierredewi...@gmail.com>

[Pierre De Wilde]

Hey,

The solution was in the excellent Troubleshooting wiki page :

curl -X POST -d "script=m=[];g.v(1).out('knows').aggregate(m);m" http://localhost:8182/tinkergraph/tp/gremlin

{"results":[],"success":true,"version":"0.4-SNAPSHOT","queryTime":3.97696}

 

curl -X POST -d "script=m=[];g.v(1).out('knows').aggregate(m)>>-1;m" http://localhost:8182/tinkergraph/tp/gremlin

{"results":[{"_id":"2","_type":"vertex","name":"vadas","age":27},{"_id":"4","_type":"vertex","name":"josh","age":32}],"success":true,"version":"0.4-SNAPSHOT","queryTime":3.68896}

Therefore, to convert graph into triples:

curl -X POST -d "script=t=new Table();g.V.name.as('s').back(1).outE.label.as('p').back(1).inV.name.as('o').back(1).table(t)>>-1;t" http://localhost:8182/tinkergraph/tp/gremlin

{"results":["[s:marko, p:knows, o:vadas]","[s:marko, p:created, o:lop]","[s:marko, p:knows, o:josh]","[s:peter, p:created, o:lop]","[s:josh, p:created, o:ripple]","[s:josh, p:created, o:lop]"],"success":true,"version":"0.4-SNAPSHOT","queryTime":5.362944}

Admittedly, I don't grasp why we need to do that... Marko?

Pierre

2011/6/12 stephen mallette <spmal...@gmail.com>

[Pierre De Wilde]

Thinking further, table results should be serialized differently.

Currently, Rexster returns:

[

"[s:marko, p:knows, o:vadas]",

"[s:marko, p:created, o:lop]",

"[s:marko, p:knows, o:josh]",

"[s:peter, p:created, o:lop]",

"[s:josh, p:created, o:ripple]",

"[s:josh, p:created, o:lop]"

]

I was expecting

[

{"s":"marko", "p":"knows", "o":"vadas"}, 

{"s":"marko", "p":"created", "o":"lop"}, 

{"s":"marko", "p":"knows", "o":"josh"}, 

{"s":"peter", "p":"created", "o":"lop"}, 

{"s":"josh", "p":"created", "o":"ripple"}, 

{"s":"josh", "p":"created", "o":"lop"}

]

Named steps combined with Table() are new stuff which leads to new clothes...

Thanks,

Pierre

2011/6/12 Pierre De Wilde <pierre...@gmail.com>

[stephen mallette]

Marko, I tried to quickly fix this, but it looks like the Row class is
protected so I can't access the iterator of Rows from the table.
Could you make that public please?

On Jun 12, 3:43 am, Pierre De Wilde <pierredewi...@gmail.com> wrote:
> Thinking further, table results should be serialized differently.
>
> Currently, Rexster returns:
> [
> "[s:marko, p:knows, o:vadas]",
> "[s:marko, p:created, o:lop]",
> "[s:marko, p:knows, o:josh]",
> "[s:peter, p:created, o:lop]",
> "[s:josh, p:created, o:ripple]",
> "[s:josh, p:created, o:lop]"
> ]
>
> I was expecting
> [
> {"s":"marko", "p":"knows", "o":"vadas"},
> {"s":"marko", "p":"created", "o":"lop"},
> {"s":"marko", "p":"knows", "o":"josh"},
> {"s":"peter", "p":"created", "o":"lop"},
> {"s":"josh", "p":"created", "o":"ripple"},
> {"s":"josh", "p":"created", "o":"lop"}
> ]
>
> Named steps combined with Table() are new stuff which leads to new
> clothes...
>
> Thanks,
> Pierre
>

> 2011/6/12 Pierre De Wilde <pierredewi...@gmail.com>
>
>
>
>
>
>
>
> > Hey,
>
> > The solution was in the excellent Troubleshooting wiki page<https://github.com/tinkerpop/gremlin/wiki/Troubleshooting>
> >  :

>
> > curl -X POST -d "script=m=[];g.v(1).out('knows').aggregate(m);m"
> >http://localhost:8182/tinkergraph/tp/gremlin
> > {"results":[],"success":true,"version":"0.4-SNAPSHOT","queryTime":3.97696}
>

> > curl -X POST -d "script=m=[];g.v(1).out('knows').aggregate(m)*>>-1*;m"
> >http://localhost:8182/tinkergraph/tp/gremlin
>
> > {"results":[{"_id":"2","_type":"vertex","name":"vadas","age":27},{"_id":"4" ,"_type":"vertex","name":"josh","age":32}],"success":true,"version":"0.4-SN APSHOT","queryTime":3.68896}

[stephen mallette]

Marko, one other point regarding the Table class: I didn't see a way
to get the column names. The addition of:

String getColumnName(int column)
List<String> columnNames getColumnNames()

would work.

[Marko Rodriguez]

Hey Pierre,

In Gremlin, when you create an expression:

g.v(1).outE.inV.blah

You are creating an iterator.

gremlin> g.v(1).outE.inV.blah.class

==>class com.tinkerpop.gremlin.pipes.GremlinPipeline

When you hit <enter> in Gremlin terminal, the terminal says: "Ah this is an iterator, let me iterate it for you and toString() the results."

When you are using Gremlin in an IDE setting (Groovy code, etc.), you will need to manually iterate the iterator yourself. You can do this with:

g.v(1).outE.inV.blah >> -1

This will just while(itty.hasNext()) { itty.next() }

That is good for filling an intermediate data structure -- e.g. groupCount(m), aggregate(x), etc. However, if there is no sideEffect in the pipeline >>-1 will do nothing but waste clock cycles :).

Get it?

Marko.

http://markorodriguez.com

[Marko Rodriguez]

Hi,

Yea, there is no Table -> JSON mapping in Rexster right now. Table is a brand new class maybe 1.5 weeks old :). If someone wants to write the implementation and contribute it, that would be good.

See: ElementJSONHelper  in Rexster for inspiration.

See ya,

Marko.

http://markorodriguez.com

[Marko Rodriguez]

Hi,

Done.
1. Table.Row is a public class.
2. There is now Table.getColumnNames().

I did not add Table.getColumnName(int column) -- simply do: Table.getColumnNames().get(int).

Code/jars In GitHub and TinkerPop Maven2, respectively.

See ya,
Marko.

http://markorodriguez.com

[stephen mallette]

Just finished the changes in Rexster to support Table...works for both
the REST API and Dog House Gremlin Console. Table is pretty awesome!

Stephen

[Pierre De Wilde]

Awesome. Was out less than 2 days and everything is implemented. 

Thanks guys,

Pierre

2011/6/12 stephen mallette <spmal...@gmail.com>

Just finished the changes in Rexster to support Table...works for both