AnormCypher: How to get a complete path for a given node?

Question

For a graph consisting of two groups of nodes:

n1 -> n2 -> n3 -> n4

and

n5 -> n6 -> n7

Created with commands:

CREATE (n1 { id:'n1' })-[:rel]->(n2 {id:'n2' })-[:rel]->(n3 { id:'n3' })-[:rel]->(n4 {id:'n4'})

CREATE (n5 { id:'n5' })-[:rel]->(n6 {id:'n6' })-[:rel]->(n7 { id:'n7' })

For both requests:

MATCH p = (n {id: 'n1'})-[*]-(m) RETURN nodes(p) as nodes;

MATCH p = (n {id: 'n1'})-[*]-(m) RETURN relationships(p) as rels ;

AnormCypher (http://anormcypher.org/) returns info related only to nodes n1 and n2, while Neo4J Web console returns a complete path.

How to get all nodes and relations for the complete path in AnormCypher?

Program that demonstrates this (at the end of this message) outputs:

ListBuffer(NeoNode(32,Map(id -> n1)), NeoNode(33,Map(id -> n2)))
Node: id=32 props=Map(id -> n1)
--Props keys:
----key: id val: n1
Node: id=33 props=Map(id -> n2)
--Props keys:
----key: id val: n2
ListBuffer(NeoRelationship(27,Map(),32,33))
Rel: id=27 start=32 end=33 props=Map()

Code:

object Simple {
   def main(args: Array[String]): Unit = {

Cypher("MATCH p = (n {id: 'n1'})-[*]-(m) RETURN nodes(p) as nodes;")().map { row =>

  println(row[Seq[org.anormcypher.NeoNode]]("nodes"))
  val nodes = row[Seq[org.anormcypher.NeoNode]]("nodes")

  nodes.map(n => {
    val props = n.props
    println("Node: id="+n.id+" props="+props)
    println("--Props keys: ")
    val x = props.keys
    props.keys.map( k=> println("----key: "+k+" val: "+props(k)))
    })
}

Cypher("MATCH p = (n {id: 'n1'})-[*]-(m) RETURN relationships(p) as rels ;")().map { row =>

  println(row[Seq[NeoRelationship]]("rels"))
  val rels = row[Seq[NeoRelationship]]("rels")
  rels.map(r => {
    val x = r.props
    println("Rel: id="+r.id+" start="+r.start+" end="+r.end+" props="+r.props)
  })
}

 }
}

Is this the right forum to ask this? Have you tried adding an issue to the AnormCypher open source repo? github.com/AnormCypher/AnormCypher/issues — cybersam
@cybersam seems reasonable to ask it here--it's not really a bug, per se. — Eve Freeman

Eve Freeman Eve Freeman · Accepted Answer · 2014-05-21T21:10:27

The problem is your map function is creating a lazy stream, and you're not iterating over the rest of the stream. If you add .toList or .last to the end of your .map, forcing the iteration over the full stream, you should get the longer path results.

For example:

Cypher("MATCH p = (n {id: 'n1'})-[*]-(m) RETURN nodes(p) as nodes;")().map { row =>
  println(row[Seq[org.anormcypher.NeoNode]]("nodes"))
  val nodes = row[Seq[org.anormcypher.NeoNode]]("nodes")

  nodes.map(n => {
    val props = n.props
    println("Node: id="+n.id+" props="+props)
    println("--Props keys: ")
    val x = props.keys
    props.keys.map( k=> println("----key: "+k+" val: "+props(k)))
    })
}.toList

Alternatively, you could just use .foreach instead of .map, which does this for you.

Update: Here's an example that has no return type:

Cypher("MATCH p = (n {id: 'n1'})-[*]-(m) RETURN nodes(p) as nodes;")().foreach { row =>
  println(row[Seq[org.anormcypher.NeoNode]]("nodes"))
  val nodes = row[Seq[org.anormcypher.NeoNode]]("nodes")

  nodes.map(n => {
    val props = n.props
    println("Node: id="+n.id+" props="+props)
    println("--Props keys: ")
    val x = props.keys
    props.keys.map( k=> println("----key: "+k+" val: "+props(k)))
    })
}

AnormCypher: How to get a complete path for a given node?

1 Answers