public abstract class CompositeOperator extends AbstractLogicalOperator
Group
operator: in the case of a key-less aggregation,
there is an initial parallel operator where partial aggregations are computed
connected to a non-parallel operator that combines the one-row from each partition
into a final result.
Here is an example of a CompositeOperator that consists of two sub-operators,
linked together:
public class MyComposite extendsCompositeOperator
{ //the input port for the composite private finalRecordPort
input=newRecordInput
("input"); //the output port for the composite private finalRecordPort
output=newRecordOutput
("output"); public MyComposite() { } //the input port for the composite publicRecordPort
getInput() { return input; } //the output port for the composite publicRecordPort
getOutput() { return output; }@Override
protected void compose(CompositionContext
ctx) { //perform any validation if (...) { throw new ...; } //add the two sub-operators SubOp1 op1= ctx.add
(new SubOp1()); SubOp2 op2= ctx.add
(new SubOp2()); //connect the composite's input port to the op1's input ctx.connect
(input,op1.getInput()); //connect op1's output to op2's input ctx.connect
(op1.getOutput(), op2.getInput()); //connect op2's output to the composite's output port ctx.connect
(op2.getOutput(), output); } }
Constructor and Description |
---|
CompositeOperator() |
Modifier and Type | Method and Description |
---|---|
protected abstract void |
compose(CompositionContext ctx)
Compose the body of this operator.
|
disableParallelism, getInputPorts, getOutputPorts, newInput, newInput, newOutput, newRecordInput, newRecordInput, newRecordOutput, notifyError
protected abstract void compose(CompositionContext ctx)
OperatorComposable.add(O)
OperatorComposable.connect(P, P)
. This includes
connections from the composite's input ports to sub-operators, connections between sub-operators, and
connections from sub-operators output ports to the composite's output portsctx
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