--- a/minecraft/server/BlockRedstoneComparator.java
+++ b/minecraft/server/BlockRedstoneComparator.java
@@ -5,6 +5,8 @@
 import java.util.Random;
 import javax.annotation.Nullable;
 
+import org.bukkit.craftbukkit.event.CraftEventFactory; // CraftBukkit
+
 public class BlockRedstoneComparator extends BlockDiodeAbstract implements ITileEntity {
 
     public static final BlockStateBoolean POWERED = BlockStateBoolean.of("powered");
@@ -164,8 +166,18 @@
             boolean flag1 = this.A(iblockdata);
 
             if (flag1 && !flag) {
+                // CraftBukkit start
+                if (CraftEventFactory.callRedstoneChange(world, blockposition.getX(), blockposition.getY(), blockposition.getZ(), 15, 0).getNewCurrent() != 0) {
+                    return;
+                }
+                // CraftBukkit end
                 world.setTypeAndData(blockposition, iblockdata.set(BlockRedstoneComparator.POWERED, Boolean.valueOf(false)), 2);
             } else if (!flag1 && flag) {
+                // CraftBukkit start
+                if (CraftEventFactory.callRedstoneChange(world, blockposition.getX(), blockposition.getY(), blockposition.getZ(), 0, 15).getNewCurrent() != 15) {
+                    return;
+                }
+                // CraftBukkit end
                 world.setTypeAndData(blockposition, iblockdata.set(BlockRedstoneComparator.POWERED, Boolean.valueOf(true)), 2);
             }