make it thread safe

1 files changed, 4 insertions, 3 deletions

diff --git a/src/main/java/gregtech/api/util/GT_Recipe.java b/src/main/java/gregtech/api/util/GT_Recipe.java
index 315d70a522..d970175560 100644
--- a/src/main/java/gregtech/api/util/GT_Recipe.java
+++ b/src/main/java/gregtech/api/util/GT_Recipe.java
@@ -23,6 +23,7 @@ import net.minecraftforge.fluids.FluidStack;
 import net.minecraftforge.fluids.IFluidContainerItem;
 
 import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static gregtech.api.enums.GT_Values.*;
@@ -388,7 +389,7 @@ public class GT_Recipe implements Comparable<GT_Recipe> {
 
         if (mInputs.length > 0 && aInputs == null) return false;
 
-        HashSet<Integer> isUsed = new HashSet<>();
+        ConcurrentHashMap<Integer, Boolean> isUsed = new ConcurrentHashMap<>();
 
         for (ItemStack tStack : mInputs) {
             ItemStack unified_tStack = GT_OreDictUnificator.get_nocopy(true, tStack);
@@ -398,8 +399,8 @@ public class GT_Recipe implements Comparable<GT_Recipe> {
                 int it = 0;
                 for (ItemStack aStack : aInputs) {
                     it ++;
-                    if (GT_OreDictUnificator.isInputStackEqual(aStack, unified_tStack) && !isUsed.contains(it)) {
-                        isUsed.add(it);
+                    if (GT_OreDictUnificator.isInputStackEqual(aStack, unified_tStack) && !isUsed.containsKey(it)) {
+                        isUsed.put(it, true);
                         if (GTppRecipeHelper) {//remove once the fix is out
                             if (GT_Utility.areStacksEqual(aStack, Ic2Items.FluidCell.copy(), true) || GT_Utility.areStacksEqual(aStack, ItemList.Tool_DataStick.get(1L), true) || GT_Utility.areStacksEqual(aStack, ItemList.Tool_DataOrb.get(1L), true)) {
                                 if (!GT_Utility.areStacksEqual(aStack, tStack, false))