Template functions for the most common neo4j queries using erictsangx/kotlin-neo4j

Neo4jQueryTemplates.kt

import github.etx.neo4j.CursorWrapper
import github.etx.neo4j.NeoQuery
import github.etx.neo4j.destruct
import github.etx.neo4j.DefaultNeoSerializer

val driver: Driver = GraphDatabase.driver(
	"bolt://localhost",
	AuthTokens.basic("neo4j", "demo")
)

val neo = NeoQuery(driver, DefaultNeoSerializer())

inline fun <reified T> CursorWrapper.convertAll(key: String) =
	map { mapper.convertValue<T>(it.unwrap(key).asMap(), T::class.java) }

inline fun <reified T> node(id: String, kv: Map<String,Any>): String {
	val props = kv.entries.joinToString { "${it.key}:{${it.value}}" }
	val cname = T::class.java.simpleName
	return "($id:$cname{$props})"
}

inline fun <reified T> node(id: String, k: Iterable<String>): String {
	val props = k.joinToString { "$it:{$it}"}
	val cname = T::class.java.simpleName
	return "($id:$cname{$props})"
}

inline fun <reified T> NeoQuery.getAll(vararg kv: Pair<String,Any>): Sequence<T> {
	val map = mapOf(*kv)
	return submit("match ${node<T>("r", map.keys)} return r", map).convertAll<T>("r")
}

inline fun <reified T> NeoQuery.getOne(vararg kv: Pair<String,Any>): T? {
	return getAll<T>(*kv).firstOrNull()
}

inline fun <reified T> NeoQuery.exists(vararg kv: Pair<String, Any>): Boolean {
	val map = mapOf(*kv)
	return submit("match ${node<T>("u", map.keys)} return count(u) > 0", map).unwrap("u").bool
}

inline fun <reified T: Any> NeoQuery.createNode(vararg nodes: T) {
	nodes.forEach { n -> submit("create ${node<T>("", propNamesOf<T>())}", n.destruct()) }
}