From 2b3ec3aec2fca17367c3fbb6ffb78991ec4d278f Mon Sep 17 00:00:00 2001
From: ioannispan <ioannis.panagiotas@neotechnology.com>
Date: Tue, 6 Aug 2024 13:27:55 +0200
Subject: [PATCH] Change the streaming mechanism

---
 .../WeightedAllShortestPaths.java             | 36 +++++++++++--------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/algo/src/main/java/org/neo4j/gds/allshortestpaths/WeightedAllShortestPaths.java b/algo/src/main/java/org/neo4j/gds/allshortestpaths/WeightedAllShortestPaths.java
index 5d4bff2885..2a2d25cf25 100644
--- a/algo/src/main/java/org/neo4j/gds/allshortestpaths/WeightedAllShortestPaths.java
+++ b/algo/src/main/java/org/neo4j/gds/allshortestpaths/WeightedAllShortestPaths.java
@@ -61,7 +61,7 @@ public class WeightedAllShortestPaths extends MSBFSASPAlgorithm {
     private final ExecutorService executorService;
     private final Graph graph;
     private final AtomicInteger counter; // nodeId counter (init with nodeCount, counts down for each node)
-
+    private final AtomicInteger runningTaskCounter = new AtomicInteger(0);
     private volatile boolean outputStreamOpen;
 
     public WeightedAllShortestPaths(Graph graph, ExecutorService executorService, Concurrency concurrency, TerminationFlag terminationFlag) {
@@ -93,6 +93,7 @@ public Stream<AllShortestPathsStreamResult> compute() {
 
         for (int i = 0; i < concurrency.value(); i++) {
             executorService.submit(new ShortestPathTask());
+            runningTaskCounter.incrementAndGet();
         }
 
         return AllShortestPathsStream.stream(resultQueue, () -> {
@@ -125,20 +126,23 @@ public void run() {
             int startNode;
             while (outputStreamOpen && terminationFlag.running() && (startNode = counter.getAndIncrement()) < nodeCount) {
                 compute(startNode);
-                for (int i = 0; i < nodeCount; i++) {
-                    var result = AllShortestPathsStreamResult.result(
-                        graph.toOriginalNodeId(startNode),
-                        graph.toOriginalNodeId(i),
-                        distance[i]
-                    );
-                    try {
-                        resultQueue.put(result);
-                    } catch (InterruptedException e) {
-                        Thread.currentThread().interrupt();
-                        throw new RuntimeException(e);
-                    }
-                }
-                progressTracker.logProgress();
+            }
+            if (runningTaskCounter.decrementAndGet() == 0 && outputStreamOpen) {
+                    resultQueue.add(AllShortestPathsStreamResult.DONE);
+            }
+        }
+
+        private  void streamResult(int source, int target, double distance){
+            var result = AllShortestPathsStreamResult.result(
+                graph.toOriginalNodeId(source),
+                graph.toOriginalNodeId(target),
+                distance
+            );
+            try {
+                resultQueue.put(result);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                throw new RuntimeException(e);
             }
         }
 
@@ -149,6 +153,7 @@ void compute(int startNode) {
             while (outputStreamOpen && !queue.isEmpty()) {
                 final int node = queue.pop();
                 final double sourceDistance = distance[node];
+                streamResult(startNode,node,sourceDistance);
                 threadLocalGraph.forEachRelationship(
                         node,
                         Double.NaN,
@@ -162,6 +167,7 @@ void compute(int startNode) {
                             return true;
                         }));
             }
+            progressTracker.logProgress();
         }
     }
 }