Operator (nebulastream-java-client 0.0.86 API)

java.lang.Object
- stream.nebula.operators.Operator

Direct Known Subclasses:

FilterOperator, InferModelOperator, JavaUdfOperator, JoinOperator, KeyedWindowOperator, LogicalSourceOperator, MapOperator, ProjectionOperator, RenameSourceOperator, UnionOperator, WatermarkStrategyOperator
```
public class Operator
extends java.lang.Object
```
The Operator class is the base class for operators which encode the manipulation of a NebulaStream source with the Query API.
A query created with NebulaStreamRuntime.readFromSource(java.lang.String) contains a LogicalSourceOperator which encodes the source stream and forms the beginning of an operator chain. Subsequent Query API calls extend the operator chain by building a (singly) linked list of Operator classes. Therefore, each Operator (except for the LogicalSourceOperator has a single child which can be accessed by the getChildOperator() of this class.
Operators which conceptually have two children, i.e., UnionOperator and JoinOperator store the second child in a branch of this main operator chain link that can be accessed through UnionOperator.getOtherQuery() and JoinOperator.getJoinedOperator().
In the Java client, Sinks are not operators because the API does not require it.

- Field Summary
  
  Fields
  Modifier and Type Field Description
  
  protected Operator childOperator
- Constructor Summary
  
  Constructors
  Constructor Description
  
  Operator(@Nullable Operator childOperator)
  Create a new operator and set its child.
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  Operator getChildOperator()
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - childOperator
```
protected final Operator childOperator
```
- Constructor Detail
  - Operator
```
public Operator(@Nullable Operator childOperator)
```
    Create a new operator and set its child.
    
    Parameters:
    
    childOperator - The child operator in a singly linked operator chain.
- Method Detail
  - getChildOperator
```
public Operator getChildOperator()
```