Fixes #3041

CHANGELOG.md

@@ -61,6 +61,7 @@
 * Fixed #3013
 * Fixed #3027
 * Fixed #2978
+* Fixed #3041
 * Possibly fixed #2927
 
 ## Release Candidate 22 (18 Apr 2021)

src/main/java/io/github/thebusybiscuit/slimefun4/core/networks/NetworkManager.java

@@ -1,9 +1,11 @@
 package io.github.thebusybiscuit.slimefun4.core.networks;
 
 import java.util.ArrayList;
-import java.util.LinkedList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.logging.Level;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -12,6 +14,7 @@ import org.apache.commons.lang.Validate;
 import org.bukkit.Location;
 import org.bukkit.Server;
 
+import io.github.thebusybiscuit.cscorelib2.blocks.BlockPosition;
 import io.github.thebusybiscuit.cscorelib2.config.Config;
 import io.github.thebusybiscuit.slimefun4.api.MinecraftVersion;
 import io.github.thebusybiscuit.slimefun4.api.network.Network;
@@ -25,6 +28,7 @@ import me.mrCookieSlime.Slimefun.api.BlockStorage;
  * and providing some utility methods that would have probably been static otherwise.
  * 
  * @author TheBusyBiscuit
+ * @author meiamsome
  * 
  * @see Network
  * @see NetworkListener
@@ -35,7 +39,16 @@ public class NetworkManager {
     private final int maxNodes;
     private final boolean enableVisualizer;
     private final boolean deleteExcessItems;
-    private final List<Network> networks = new LinkedList<>();
+
+    /**
+     * Fixes #3041
+     * 
+     * We use a {@link CopyOnWriteArrayList} here to ensure thread-safety.
+     * This {@link List} is also much more frequently read than being written to.
+     * Therefore a {@link CopyOnWriteArrayList} should be perfect for this, even
+     * if insertions come at a slight cost.
+     */
+    private final List<Network> networks = new CopyOnWriteArrayList<>();
 
     /**
      * This creates a new {@link NetworkManager} with the given capacity.
@@ -96,12 +109,13 @@ public class NetworkManager {
 
     /**
      * This returns a {@link List} of every {@link Network} on the {@link Server}.
+     * The returned {@link List} is not modifiable.
      * 
      * @return A {@link List} containing every {@link Network} on the {@link Server}
      */
     @Nonnull
     public List<Network> getNetworkList() {
-        return networks;
+        return Collections.unmodifiableList(networks);
     }
 
     @Nonnull
@@ -172,26 +186,30 @@ public class NetworkManager {
     public void updateAllNetworks(@Nonnull Location l) {
         Validate.notNull(l, "The Location cannot be null");
 
-        /*
-         * No need to create a sublist and loop through it if
-         * there aren't even any networks on the server.
-         */
-        if (networks.isEmpty()) {
-            return;
-        }
+        try {
+            /*
+             * No need to create a sublist and loop through it if
+             * there aren't even any networks on the server.
+             */
+            if (networks.isEmpty()) {
+                return;
+            }
 
-        /*
-         * Only a Slimefun block can be part of a Network.
-         * This check helps to speed up performance.
-         * 
-         * (Skip for Unit Tests as they don't support block info yet)
-         */
-        if (!BlockStorage.hasBlockInfo(l) && SlimefunPlugin.getMinecraftVersion() != MinecraftVersion.UNIT_TEST) {
-            return;
-        }
+            /*
+             * Only a Slimefun block can be part of a Network.
+             * This check helps to speed up performance.
+             * 
+             * (Skip for Unit Tests as they don't support block info yet)
+             */
+            if (!BlockStorage.hasBlockInfo(l) && SlimefunPlugin.getMinecraftVersion() != MinecraftVersion.UNIT_TEST) {
+                return;
+            }
 
-        for (Network network : getNetworksFromLocation(l, Network.class)) {
-            network.markDirty(l);
+            for (Network network : getNetworksFromLocation(l, Network.class)) {
+                network.markDirty(l);
+            }
+        } catch (Exception x) {
+            SlimefunPlugin.logger().log(Level.SEVERE, x, () -> "An Exception was thrown while causing a networks update @ " + new BlockPosition(l));
         }
     }