iot.jcypher.query.factories.xpression

Class C

java.lang.Object

iot.jcypher.query.factories.xpression.C

public class C
extends Object

JCYPHER FACTORY FOR COLLECTION EXPRESSIONS

Constructor Summary

Constructors

Constructor and Description
C()

Method Summary

Methods

Modifier and Type	Method and Description
static EXProperty<CollectFrom>	COLLECT() JCYPHER collect properties from a collection of property containers (nodes or relations), ignore NULL s e.g. ...
static CTerminal	CREATE(IClause[] clauses) JCYPHER create a collection using a list of clauses.
static ExtractExpression	EXTRACT() JCYPHER go through a collection, run an expression on every element of the collection, and return the results as a collection of these values e.g. ...
static CFrom<CWhere>	FILTER() JCYPHER return all the elements in a collection that hold true for a predicate expression e.g. ...
static CFrom<ReduceTo>	REDUCE() JCYPHER run an expression against individual elements of a collection and store the result of the expression in an accumulator e.g. ...
static Collection	TAIL() JCYPHER return all but the first element in a collection e.g. ...
static CTerminal	TAIL(JcCollection collection) JCYPHER return all but the first element in a collection e.g. ...

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

C

public C()

Method Detail

COLLECT

public static EXProperty<CollectFrom> COLLECT()

JCYPHER

collect properties from a collection of property containers (nodes or relations), ignore NULL s

e.g. ...COLLECT().property("name").from(p.nodes)

CREATE

public static CTerminal CREATE(IClause[] clauses)

JCYPHER

create a collection using a list of clauses.

This allows to use complex statements as e.g. CASE WHEN ... to create collections

e.g. ...

C.CREATE(new IClause[]{
        CASE.result(),
        WHEN.valueOf(n.property("firstName")).EQUALS("John"),
          NATIVE.cypher("[1]"),
        ELSE.perform(),
          NATIVE.cypher("[]"),
        END.caseXpr()
        })

This will create an array of size 1 if property firstName equals 'John' and an empty array otherwise.
You can then e.g. use a FOR_EACH loop to conditionally execute statements.

EXTRACT

public static ExtractExpression EXTRACT()

JCYPHER

go through a collection, run an expression on every element of the collection,
and return the results as a collection of these values

e.g. ...EXTRACT().valueOf(n.numberProperty("age").div(2)).fromAll(n).IN_nodes(p)

FILTER

public static CFrom<CWhere> FILTER()

JCYPHER

return all the elements in a collection that hold true for a predicate expression

e.g. ...FILTER().fromAll(x).IN(a.collectionProperty("array")).WHERE()...

REDUCE

public static CFrom<ReduceTo> REDUCE()

JCYPHER

run an expression against individual elements of a collection
and store the result of the expression in an accumulator

e.g. ...REDUCE()
.fromAll(n).IN_nodes(p)
.to(totalAge)
.by(totalAge.plus(n.numberProperty("age")))
.startWith(0)

TAIL

public static Collection TAIL()

JCYPHER

return all but the first element in a collection

e.g. ...TAIL().FILTER()...

TAIL

public static CTerminal TAIL(JcCollection collection)

JCYPHER

return all but the first element in a collection

e.g. ...TAIL(p.nodes())