Package stream.nebula.operators

Class JoinOperator

java.lang.Object

stream.nebula.operators.Operator

stream.nebula.operators.JoinOperator

public class JoinOperator
extends Operator

Operator class that encodes the Query.joinWith(stream.nebula.runtime.Query) method.

This class follows the builder pattern. Methods such as Query.joinWith(stream.nebula.runtime.Query), JoinOperator.JoinWhere.where(stream.nebula.expression.FieldAccessExpression), and JoinOperator.JoinEqualsTo.equalsTo(stream.nebula.expression.FieldAccessExpression) return the helper classes JoinOperator.JoinWhere, JoinOperator.JoinEqualsTo and JoinOperator.JoinWindow which manipulate the state of this JoinOperator instance; finally JoinOperator.JoinWindow.window(stream.nebula.operators.window.TimeBasedWindowDefinition) returns the original Query instance.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	JoinOperator.JoinEqualsTo	Helper inner class to set the right-hand-side joined attributed in the JoinOperator.JoinEqualsTo.equalsTo(stream.nebula.expression.FieldAccessExpression) method.
class	JoinOperator.JoinWhere	Helper inner class to set the left-hand-side joined attributed in the JoinOperator.JoinWhere.where(stream.nebula.expression.FieldAccessExpression) method.
class	JoinOperator.JoinWindow	Helper inner class to define the join window in the JoinOperator.JoinWindow.window(stream.nebula.operators.window.TimeBasedWindowDefinition) method.

Field Summary

Fields inherited from class stream.nebula.operators.Operator

childOperator

Constructor Summary

Constructors

Constructor	Description
JoinOperator(@NonNull Operator childOperator, @NonNull Query joinedQuery, @NonNull Query query)	Create a new JoinOperator which joins query on the left-hand-side with otherQuery on the right-hand-side.

Method Summary

Modifier and Type	Method	Description
Operator	getJoinedOperator()	Access the joined query.
FieldAccessExpression	getLhs()	Access the left-hand-side attribute of this JoinOperator.
FieldAccessExpression	getRhs()	Access the right-hand-side attribute of this JoinOperator.
TimeBasedWindowDefinition	getWindowDefinition()	Access the join window definition of this JoinOperator.

Methods inherited from class stream.nebula.operators.Operator

getChildOperator

Methods inherited from class java.lang.Object

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

Constructor Detail

JoinOperator

public JoinOperator(@NonNull Operator childOperator,
                    @NonNull Query joinedQuery,
                    @NonNull Query query)
             throws java.lang.IllegalArgumentException

Create a new JoinOperator which joins query on the left-hand-side with otherQuery on the right-hand-side.

Parameters:

childOperator - The previous operator in the operator chain of query.

joinedQuery - The joined query.

query - The Query instance on which Query.joinWith(stream.nebula.runtime.Query) was called.

Throws:

java.lang.IllegalArgumentException - If joinedQuery is null.

Method Detail

getJoinedOperator

public Operator getJoinedOperator()

Access the joined query.

Returns:

The joined query.

getLhs

public FieldAccessExpression getLhs()

Access the left-hand-side attribute of this JoinOperator.

Returns:

The left-hand-side join attribute.

getRhs

public FieldAccessExpression getRhs()

Access the right-hand-side attribute of this JoinOperator.

Returns:

The right-hand-side join attribute.

getWindowDefinition

public TimeBasedWindowDefinition getWindowDefinition()

Access the join window definition of this JoinOperator.

Returns:

The join window.