Add checkstyle validation for formatting, fix issues

config/checkstyle/checkstyle.xml

@@ -53,5 +53,13 @@
     <!-- <module name="PackageName"/> Unlikely that we would miss this in a PR -->
     <module name="ParameterName"/>
     <!-- <module name="TypeName"/> Unlikely that we would miss this in a PR -->
+    <!-- Validate assignment operators -->
+    <module name="WhitespaceAround">
+      <property name="tokens" value="ASSIGN"/>
+    </module>
+  </module>
+  <!-- Validate that command annotations are formatted correctly -->
+  <module name="RegexpMultiline">
+    <property name="format" value="^( +)@(Arg|Switch|Command)\(.*?\n\1 {5,}"/>
   </module>
 </module>

worldedit-core/src/legacy/java/com/sk89q/worldedit/blocks/MobSpawnerBlock.java

@@ -90,7 +90,7 @@ public class MobSpawnerBlock extends BaseBlock {
 
     /**
      * Get the spawn delay.
-     * 
+     *
      * @return the delay
      */
     public short getDelay() {
@@ -99,13 +99,13 @@ public class MobSpawnerBlock extends BaseBlock {
 
     /**
      * Set the spawn delay.
-     * 
+     *
      * @param delay the delay to set
      */
     public void setDelay(short delay) {
         this.delay = delay;
     }
-    
+
     @Override
     public boolean hasNbtData() {
         return true;
@@ -208,7 +208,7 @@ public class MobSpawnerBlock extends BaseBlock {
             this.spawnCount = spawnCountTag.getValue();
         }
         if (spawnRangeTag != null) {
-            this.spawnRange =spawnRangeTag.getValue();
+            this.spawnRange = spawnRangeTag.getValue();
         }
         if (minSpawnDelayTag != null) {
             this.minSpawnDelay = minSpawnDelayTag.getValue();

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

@@ -19,8 +19,6 @@
 
 package com.sk89q.worldedit.command;
 
-import static com.sk89q.worldedit.command.util.Logging.LogMode.REGION;
-
 import com.sk89q.worldedit.EditSession;
 import com.sk89q.worldedit.LocalSession;
 import com.sk89q.worldedit.WorldEdit;
@@ -59,6 +57,8 @@ import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
+import static com.sk89q.worldedit.command.util.Logging.LogMode.REGION;
+
 /**
  * Implements biome-related commands such as "/biomelist".
  */
@@ -97,9 +97,9 @@ public class BiomeCommands {
     )
     @CommandPermissions("worldedit.biome.info")
     public void biomeInfo(Player player, LocalSession session,
-                          @Switch(name = 't', desc="Use the block you are looking at.")
+                          @Switch(name = 't', desc = "Use the block you are looking at.")
                               boolean useLineOfSight,
-                          @Switch(name = 'p', desc="Use the block you are currently in.")
+                          @Switch(name = 'p', desc = "Use the block you are currently in.")
                               boolean usePosition) throws WorldEditException {
         BiomeRegistry biomeRegistry = WorldEdit.getInstance().getPlatformManager()
                 .queryCapability(Capability.GAME_HOOKS).getRegistries().getBiomeRegistry();

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

@@ -223,9 +223,9 @@ public class GeneralCommands {
                            @Arg(desc = "Item query")
                                String query,
                            @Switch(name = 'b', desc = "Only search for blocks")
-                                   boolean blocksOnly,
+                               boolean blocksOnly,
                            @Switch(name = 'i', desc = "Only search for items")
-                                   boolean itemsOnly) throws WorldEditException {
+                               boolean itemsOnly) throws WorldEditException {
         ItemType type = ItemTypes.get(query);
 
         if (type != null) {

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

@@ -227,8 +227,8 @@ public class GenerationCommands {
     }
 
     @Command(
-            name = "/hpyramid",
+        name = "/hpyramid",
-            desc = "Generate a hollow pyramid"
+        desc = "Generate a hollow pyramid"
     )
     @CommandPermissions("worldedit.generation.pyramid")
     @Logging(PLACEMENT)

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

@@ -137,8 +137,8 @@ public class ToolCommands {
     }
 
     @Command(
-            name = "deltree",
+        name = "deltree",
-            desc = "Floating tree remover tool"
+        desc = "Floating tree remover tool"
     )
     @CommandPermissions("worldedit.tool.deltree")
     public void deltree(Player player, LocalSession session) throws WorldEditException {
@@ -150,8 +150,8 @@ public class ToolCommands {
     }
 
     @Command(
-            name = "farwand",
+        name = "farwand",
-            desc = "Wand at a distance tool"
+        desc = "Wand at a distance tool"
     )
     @CommandPermissions("worldedit.tool.farwand")
     public void farwand(Player player, LocalSession session) throws WorldEditException {