Handle running multiple platforms at a time better.

src/main/java/com/sk89q/worldedit/extension/platform/Platform.java

@@ -89,4 +89,31 @@ public interface Platform {
      */
     LocalConfiguration getConfiguration();
 
+    /**
+     * Get the version of WorldEdit that this platform provides.
+     * </p>
+     * This version should match WorldEdit releases because it may be
+     * checked to match.
+     *
+     * @return the version
+     */
+    String getVersion();
+
+    /**
+     * Get a friendly name of the platform.
+     * </p>
+     * The name can be anything (reasonable). An example name may be
+     * "Bukkit" or "Forge".
+     *
+     * @return the platform name
+     */
+    String getPlatformName();
+
+    /**
+     * Get the version of the platform, which can be anything.
+     *
+     * @return the platform version
+     */
+    String getPlatformVersion();
+
 }

src/main/java/com/sk89q/worldedit/extension/platform/PlatformManager.java

@@ -64,11 +64,30 @@ public class PlatformManager {
      */
     public synchronized void register(Platform platform) throws PlatformRejectionException {
         checkNotNull(platform);
-        logger.log(Level.INFO, "Got request to register " + platform.getClass() + " with WorldEdit [" + super.toString() + "]");
+        logger.log(Level.FINE, "Got request to register " + platform.getClass() + " with WorldEdit [" + super.toString() + "]");
         platforms.add(platform);
+
+        // Register primary platform
         if (this.primary == null) {
             commandManager.register(platform);
             this.primary = platform;
+        } else {
+            // Make sure that versions are in sync
+            if (!primary.getVersion().equals(platform.getVersion())) {
+                logger.log(Level.WARNING,
+                        "\n**********************************************\n" +
+                        "** There is a mismatch in available WorldEdit platforms!\n" +
+                        "**\n" +
+                        "** {0} v{1} is trying to register WE version v{2}\n" +
+                        "** but the primary platform, {3} v{4}, uses WE version v{5}\n" +
+                        "**\n" +
+                        "** Things may break! Please make sure that your WE versions are in sync.\n" +
+                        "**********************************************\n",
+                        new Object[]{
+                                platform.getClass(), platform.getPlatformVersion(), platform.getVersion(),
+                                primary.getClass(), primary.getPlatformVersion(), primary.getVersion()
+                        });
+            }
         }
     }
 
@@ -91,6 +110,26 @@ public class PlatformManager {
         return removed;
     }
 
+    /**
+     * Get a list of loaded platforms.
+     * </p>
+     * The returned list is a copy of the original and is mutable.
+     *
+     * @return a list of platforms
+     */
+    public synchronized List<Platform> getPlatforms() {
+        return new ArrayList<Platform>(platforms);
+    }
+
+    /**
+     * Get the primary platform.
+     *
+     * @return the primary platform (may be null)
+     */
+    public @Nullable Platform getPrimaryPlatform() {
+        return primary;
+    }
+
     /**
      * Get the command manager.
      *

src/main/java/com/sk89q/worldedit/extension/platform/ServerInterfaceAdapter.java

@@ -91,4 +91,19 @@ class ServerInterfaceAdapter extends ServerInterface {
         return platform.getConfiguration();
     }
 
+    @Override
+    public String getVersion() {
+        return platform.getVersion();
+    }
+
+    @Override
+    public String getPlatformName() {
+        return platform.getPlatformName();
+    }
+
+    @Override
+    public String getPlatformVersion() {
+        return platform.getPlatformVersion();
+    }
+
 }