}
try {
// Insert a split and its corresponding SplitOutput nodes into the plan
// between node 0 and 1 / 2.
String scope = nodes.get(0).getOperatorKey().scope;
NodeIdGenerator idGen = NodeIdGenerator.getGenerator();
LOSplit splitOp = new LOSplit(mPlan, new OperatorKey(scope,
idGen.getNextNodeId(scope)), new ArrayList<LogicalOperator>());
splitOp.setAlias(nodes.get(0).getAlias());
mPlan.add(splitOp);
// Find all the successors and connect appropriately with split
// and splitoutput operators. Keep our own copy
// of the list, as we're changing the graph by doing these calls
// and that will change the list of predecessors.
List<LogicalOperator> succs =
new ArrayList<LogicalOperator>(mPlan.getSuccessors(nodes.get(0)));
int index = -1;
// For two successors of nodes.get(0) here is a pictorial
// representation of the change required:
// BEFORE:
// Succ1 Succ2
// \ /
// nodes.get(0)
// SHOULD BECOME:
// AFTER:
// Succ1 Succ2
// | |
// SplitOutput SplitOutput
// \ /
// Split
// |
// nodes.get(0)
// Here is how this will be accomplished.
// First (the same) Split Operator will be "inserted between" nodes.get(0)
// and all its successors. The "insertBetween" API is used which makes sure
// the ordering of operators in the graph is preserved. So we get the following:
// Succ1 Succ2
// | |
// Split Split
// \ /
// nodes.get(0)
// Then all but the first connection between nodes.get(0) and the Split
// Operator are removed using "disconnect" - so we get the following:
// Succ1 Succ2
// \ /
// Split
// |
// nodes.get(0)
// Now a new SplitOutputOperator is "inserted between" the Split operator
// and the successors. So we get:
// Succ1 Succ2
// | |
// SplitOutput SplitOutput
// \ /
// Split
// |
// nodes.get(0)
for (LogicalOperator succ : succs) {
mPlan.insertBetween(nodes.get(0), splitOp, succ);
}
for(int i = 1; i < succs.size(); i++) {
mPlan.disconnect(nodes.get(0), splitOp);
}
for (LogicalOperator succ : succs) {
LogicalPlan condPlan = new LogicalPlan();
LOConst cnst = new LOConst(mPlan, new OperatorKey(scope,
idGen.getNextNodeId(scope)), Boolean.valueOf(true));
cnst.setType(DataType.BOOLEAN);
condPlan.add(cnst);
LOSplitOutput splitOutput = new LOSplitOutput(mPlan,
new OperatorKey(scope, idGen.getNextNodeId(scope)), ++index, condPlan);
splitOp.addOutput(splitOutput);
mPlan.add(splitOutput);
mPlan.insertBetween(splitOp, splitOutput, succ);
splitOutput.setAlias(splitOp.getAlias());
}