From 32f61540d7bf4d15f1ae5fa1b8cf56789f4ee207 Mon Sep 17 00:00:00 2001
From: Tuukka Lehtonen <tuukka.lehtonen@semantum.fi>
Date: Wed, 26 Sep 2018 00:03:39 +0300
Subject: [PATCH] Prevent ConcurrentModificationException in
 StyledRouteGraphRenderer

Fixed via ThreadLocal-based caching of reused data structures.

gitlab #132

Change-Id: I42a3d3a160f1f7a9ed30d10cca84e1dc5b6488fa
---
 .../rendering/StyledRouteGraphRenderer.java      | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/bundles/org.simantics.diagram.connection/src/org/simantics/diagram/connection/rendering/StyledRouteGraphRenderer.java b/bundles/org.simantics.diagram.connection/src/org/simantics/diagram/connection/rendering/StyledRouteGraphRenderer.java
index b084e5875..dd9473042 100644
--- a/bundles/org.simantics.diagram.connection/src/org/simantics/diagram/connection/rendering/StyledRouteGraphRenderer.java
+++ b/bundles/org.simantics.diagram.connection/src/org/simantics/diagram/connection/rendering/StyledRouteGraphRenderer.java
@@ -36,9 +36,13 @@ public class StyledRouteGraphRenderer implements IRouteGraphRenderer, Serializab
 
 	protected final ConnectionStyle style;
 
+	private static class Cache {
+		Path2D path = new Path2D.Double();
+		THashSet<RoutePoint> branchPoints = new THashSet<>();
+	}
+
 	// Caches to avoid creating new objects all the time during rendering
-	protected transient Path2D path;
-	protected transient THashSet<RoutePoint> branchPoints;
+	protected static ThreadLocal<Cache> caches = ThreadLocal.withInitial(() -> new Cache());
 
 	public StyledRouteGraphRenderer(ConnectionStyle style) {
 		if (style == null)
@@ -52,14 +56,14 @@ public class StyledRouteGraphRenderer implements IRouteGraphRenderer, Serializab
 
 	@Override
 	public void render(Graphics2D g, RouteGraph rg) {
-		if (path == null)
-			path = new Path2D.Double();
+		Cache cache = caches.get();
+		Path2D path = cache.path;
+		THashSet<RoutePoint> branchPoints = cache.branchPoints;
+
 		path.reset();
 		rg.getPath2D(path);
 		style.drawPath(g, path, false);
 
-		if (branchPoints == null)
-			branchPoints = new THashSet<RoutePoint>();
 		branchPoints.clear();
 		for(RouteLine line : rg.getLines()) {
 		    renderLine(g, line, false);
-- 
2.43.2