fix more compile errors

worldedit-core/src/main/java/com/boydti/fawe/beta/DelegateFilterBlock.java

@@ -650,6 +650,11 @@ public class DelegateFilterBlock extends FilterBlock {
         return parent.getBlock(position);
     }
 
+    @Override
+    public BlockType getBlockType(BlockVector3 position) {
+        return parent.getBlockType(position);
+    }
+
     @Override
     public BaseBlock getFullBlock(BlockVector3 position) {
         return parent.getFullBlock(position);

worldedit-core/src/main/java/com/boydti/fawe/object/FawePlayer.java

@@ -265,18 +265,18 @@ public abstract class FawePlayer<T> extends Metadatable {
 
     // Queue for async tasks
     private AtomicInteger runningCount = new AtomicInteger();
-    private SimpleAsyncNotifyQueue asyncNotifyQueue = new SimpleAsyncNotifyQueue((t, e) -> {
-        while (e.getCause() != null) {
-            e = e.getCause();
+    private SimpleAsyncNotifyQueue asyncNotifyQueue = new SimpleAsyncNotifyQueue((thread, throwable) -> {
+        while (throwable.getCause() != null) {
+            throwable = throwable.getCause();
         }
-        if (e instanceof WorldEditException) {
-            sendMessage(e.getLocalizedMessage());
+        if (throwable instanceof WorldEditException) {
+            sendMessage(throwable.getLocalizedMessage());
         } else {
-            FaweException fe = FaweException.get(e);
+            FaweException fe = FaweException.get(throwable);
             if (fe != null) {
                 sendMessage(fe.getMessage());
             } else {
-                e.printStackTrace();
+                throwable.printStackTrace();
             }
         }
     });

worldedit-core/src/main/java/com/sk89q/worldedit/EditSession.java

@@ -103,6 +103,7 @@ import com.sk89q.worldedit.internal.expression.runtime.ExpressionTimeoutExceptio
 import com.sk89q.worldedit.internal.expression.runtime.RValue;
 import com.sk89q.worldedit.math.BlockVector2;
 import com.sk89q.worldedit.math.BlockVector3;
+import com.sk89q.worldedit.math.MathUtils;
 import com.sk89q.worldedit.math.MutableBlockVector2;
 import com.sk89q.worldedit.math.MutableBlockVector3;
 import com.sk89q.worldedit.math.Vector2;
@@ -1403,6 +1404,29 @@ public class EditSession extends AbstractDelegateExtent implements SimpleWorld,
         return replaceBlocks(region, mask, pattern);
     }
 
+    /**
+     * Sets the blocks at the center of the given region to the given pattern.
+     * If the center sits between two blocks on a certain axis, then two blocks
+     * will be placed to mark the center.
+     *
+     * @param region the region to find the center of
+     * @param pattern the replacement pattern
+     * @return the number of blocks placed
+     * @throws MaxChangedBlocksException thrown if too many blocks are changed
+     */
+    public int center(Region region, Pattern pattern) throws MaxChangedBlocksException {
+        checkNotNull(region);
+        checkNotNull(pattern);
+
+        Vector3 center = region.getCenter();
+        Region centerRegion = new CuboidRegion(
+            getWorld(), // Causes clamping of Y range
+            BlockVector3.at(((int) center.getX()), ((int) center.getY()), ((int) center.getZ())),
+            BlockVector3.at(MathUtils.roundHalfUp(center.getX()),
+                center.getY(), MathUtils.roundHalfUp(center.getZ())));
+        return setBlocks(centerRegion, pattern);
+    }
+
     /**
      * Make the faces of the given region as if it was a {@link CuboidRegion}.
      *

worldedit-core/src/main/java/com/sk89q/worldedit/command/ClipboardCommands.java

@@ -126,7 +126,8 @@ public class ClipboardCommands {
         BlockVector3 min = region.getMinimumPoint();
         BlockVector3 max = region.getMaximumPoint();
 
-        long volume = (((long) max.getX() - (long) min.getX() + 1) * ((long) max.getY() - (long) min.getY() + 1) * ((long) max.getZ() - (long) min.getZ() + 1));
+        long volume =
+            ((long) max.getX() - (long) min.getX() + 1) * ((long) max.getY() - (long) min.getY() + 1) * ((long) max.getZ() - (long) min.getZ() + 1);
         FaweLimit limit = FawePlayer.wrap(player).getLimit();
         if (volume >= limit.MAX_CHECKS) {
             throw FaweException.MAX_CHECKS;

worldedit-core/src/main/java/com/sk89q/worldedit/command/MaskCommands.java

@@ -88,8 +88,7 @@ public class MaskCommands {
     }
 
     @Command(
-            name = "false",
-            aliases = {"#false"},
+            name = "#false",
             desc = "Always false"
     )
     public Mask falseMask(Extent extent) {
@@ -97,8 +96,7 @@ public class MaskCommands {
     }
 
     @Command(
-            name = "true",
-            aliases = {"#true"},
+            name = "#true",
             desc = "Always true"
     )
     public Mask trueMask(Extent extent) {

worldedit-core/src/main/java/com/sk89q/worldedit/command/RegionCommands.java

@@ -547,7 +547,7 @@ public class RegionCommands {
                          boolean skipEntities,
                      @Switch(name = 'a', desc = "Ignore air blocks")
                          boolean ignoreAirBlocks,
-                     @Switch(name = 'm', desc = "Source mask")
+                     @ArgFlag(name = "m", desc = "Source mask")
                          Mask sourceMask,
                     InjectedValueAccess context) throws WorldEditException {
         player.checkConfirmationStack(() -> {
@@ -677,7 +677,7 @@ public class RegionCommands {
                           int thickness,
                       @Arg(desc = "The pattern of blocks to replace the hollowed area with", def = "air")
                           Pattern pattern,
-        @Switch(name = 'm', desc = "Mask to hollow with") Mask mask,
+        @ArgFlag(name = "m", desc = "Mask to hollow with") Mask mask,
                        InjectedValueAccess context) throws WorldEditException {
         checkCommandArgument(thickness >= 0, "Thickness must be >= 0");
         Mask finalMask = mask == null ? new SolidBlockMask(editSession) : mask;

worldedit-core/src/main/java/com/sk89q/worldedit/command/SchematicCommands.java

@@ -577,7 +577,7 @@ public class SchematicCommands {
                          boolean oldFirst,
                      @Switch(name = 'n', desc = "Sort by date, newest first")
                          boolean newFirst,
-                     @Switch(name = 'f', desc = "Restricts by format.")
+                     @ArgFlag(name = 'f', desc = "Restricts by format.")
                          String formatName,
                     @Arg(name = "filter", desc = "Filter for schematics", def = "all")
                         String filter) throws WorldEditException {

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/Actor.java

@@ -83,7 +83,7 @@ public interface Actor extends Identifiable, SessionOwner, Subject {
      */
     void print(Component component);
 
-    /**
+    /**F
      * Returns true if the actor can destroy bedrock.
      *
      * @return true if bedrock can be broken by the actor

worldedit-core/src/main/java/com/sk89q/worldedit/extent/Extent.java

@@ -52,7 +52,6 @@ import com.sk89q.worldedit.registry.state.PropertyGroup;
 import com.sk89q.worldedit.session.ClipboardHolder;
 import com.sk89q.worldedit.util.Countable;
 import com.sk89q.worldedit.util.Location;
-import com.sk89q.worldedit.world.World;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockState;
@@ -620,8 +619,4 @@ public interface Extent extends InputExtent, OutputExtent {
         return count;
     }
 
-    default World getWorld() {
-        return null;
-    }
-
 }