public LoopVertex unRollIteration()

in common/src/main/java/org/apache/nemo/common/ir/vertex/LoopVertex.java [314:365]
40 lines of code
2 McCabe index (conditional complexity)

  public LoopVertex unRollIteration(final DAGBuilder<IRVertex, IREdge> dagBuilder) {
    final HashMap<IRVertex, IRVertex> originalToNewIRVertex = new HashMap<>();
    final DAG<IRVertex, IREdge> dagToAdd = getDAG();

    decreaseMaxNumberOfIterations();

    // add the DAG and internal edges to the dagBuilder.
    dagToAdd.topologicalDo(irVertex -> {
      final IRVertex newIrVertex = irVertex.getClone();
      originalToNewIRVertex.putIfAbsent(irVertex, newIrVertex);

      dagBuilder.addVertex(newIrVertex, dagToAdd);
      dagToAdd.getIncomingEdgesOf(irVertex).forEach(edge -> {
        final IRVertex newSrc = originalToNewIRVertex.get(edge.getSrc());
        final IREdge newIrEdge =
          new IREdge(edge.getPropertyValue(CommunicationPatternProperty.class).get(), newSrc, newIrVertex);
        edge.copyExecutionPropertiesTo(newIrEdge);
        dagBuilder.connectVertices(newIrEdge);
      });
    });

    // process the initial DAG incoming edges for the first loop.
    getDagIncomingEdges().forEach((dstVertex, irEdges) -> irEdges.forEach(edge -> {
      final IREdge newIrEdge = new IREdge(edge.getPropertyValue(CommunicationPatternProperty.class).get(),
        edge.getSrc(), originalToNewIRVertex.get(dstVertex));
      edge.copyExecutionPropertiesTo(newIrEdge);
      dagBuilder.connectVertices(newIrEdge);
    }));

    if (loopTerminationConditionMet()) {
      // if termination condition met, we process the last DAG outgoing edges for the final loop. Otherwise, we leave it
      getDagOutgoingEdges().forEach((srcVertex, irEdges) -> irEdges.forEach(edge -> {
        final IREdge newIrEdge = new IREdge(edge.getPropertyValue(CommunicationPatternProperty.class).get(),
          originalToNewIRVertex.get(srcVertex), edge.getDst());
        edge.copyExecutionPropertiesTo(newIrEdge);
        dagBuilder.addVertex(edge.getDst()).connectVertices(newIrEdge);
      }));
    }

    // process next iteration's DAG incoming edges, and add them as the next loop's incoming edges:
    // clear, as we're done with the current loop and need to prepare it for the next one.
    this.getDagIncomingEdges().clear();
    this.nonIterativeIncomingEdges.forEach((dstVertex, irEdges) -> irEdges.forEach(this::addDagIncomingEdge));
    this.iterativeIncomingEdges.forEach((dstVertex, irEdges) -> irEdges.forEach(edge -> {
      final IREdge newIrEdge = new IREdge(edge.getPropertyValue(CommunicationPatternProperty.class).get(),
        originalToNewIRVertex.get(edge.getSrc()), dstVertex);
      edge.copyExecutionPropertiesTo(newIrEdge);
      this.addDagIncomingEdge(newIrEdge);
    }));

    return this;
  }