Suppress ender crystal drops in a radius around the end portal (end s…

…ide) to prevent their recovery when the dragon has already started spawning.

config.yml

@@ -0,0 +1,10 @@
+end-portal:
+  radius: 7.0
+  location:
+    ==: org.bukkit.Location
+    world: world_the_end
+    x: 0.0
+    y: 62.0
+    z: 0.0
+    pitch: 0.0
+    yaw: 0.0

pom.xml

@@ -4,7 +4,7 @@
 	<groupId>nu.nerd</groupId>
 	<name>SafeCrystals</name>
 	<artifactId>${project.name}</artifactId>
-	<version>0.1.0</version>
+	<version>1.0.0</version>
 	<packaging>jar</packaging>
 	<description>Prevent Ender Crystals from exploding and breaking blocks or damaging entities.</description>
 	<url>https://github.com/totemo/${project.name}</url>
@@ -48,6 +48,7 @@
 				<directory>${basedir}</directory>
 				<includes>
 					<include>plugin.yml</include>
+					<include>config.yml</include>
 				</includes>
 			</resource>
 		</resources>

src/nu/nerd/safecrystals/Configuration.java

@@ -0,0 +1,30 @@
+package nu.nerd.safecrystals;
+
+import org.bukkit.Location;
+
+// ----------------------------------------------------------------------------
+/**
+ * Configuration wrapper.
+ */
+public class Configuration {
+    /**
+     * Radius around END_PORTAL_LOCATION where broken ender crystals don't drop.
+     */
+    public double END_PORTAL_RADIUS;
+
+    /**
+     * Location of the (assumed only) end-side end portal.
+     */
+    public Location END_PORTAL_LOCATION;
+
+    // ------------------------------------------------------------------------
+    /**
+     * Reload the configuration.
+     */
+    public void reload() {
+        SafeCrystals.PLUGIN.reloadConfig();
+
+        END_PORTAL_RADIUS = SafeCrystals.PLUGIN.getConfig().getDouble("end-portal.radius");
+        END_PORTAL_LOCATION = (Location) SafeCrystals.PLUGIN.getConfig().get("end-portal.location");
+    }
+} // class Configuration

src/nu/nerd/safecrystals/SafeCrystals.java

@@ -32,13 +32,26 @@
  * Ender Crystal in a region.
  */
 public class SafeCrystals extends JavaPlugin implements Listener {
+    /**
+     * Singleton-like reference to this plugin.
+     */
+    public static SafeCrystals PLUGIN;
+
+    /**
+     * Configuration instance.
+     */
+    public static Configuration CONFIG = new Configuration();
 
     // ------------------------------------------------------------------------
     /**
      * @see org.bukkit.plugin.java.JavaPlugin#onEnable()
      */
     @Override
     public void onEnable() {
+        PLUGIN = this;
+        saveDefaultConfig();
+        CONFIG.reload();
+
         _worldGuard = (WorldGuardPlugin) getServer().getPluginManager().getPlugin("WorldGuard");
         Bukkit.getPluginManager().registerEvents(this, this);
     }
@@ -110,13 +123,43 @@ protected void tryBreakEnderCrystal(Entity crystal, Player player) {
         Location loc = crystal.getLocation();
         if (_worldGuard.canBuild(player, loc)) {
             crystal.remove();
-            loc.getWorld().dropItemNaturally(loc, new ItemStack(Material.END_CRYSTAL));
+            String suppressed;
+            if (isDragonSpawningCrystal(loc)) {
+                suppressed = " - drop suppressed because dragon may spawn";
+            } else {
+                loc.getWorld().dropItemNaturally(loc, new ItemStack(Material.END_CRYSTAL));
+                suppressed = "";
+            }
             getLogger().info(player.getName() + " broke an Ender Crystal at " +
                              loc.getWorld().getName() + ", " +
-                             loc.getBlockX() + ", " + loc.getBlockY() + ", " + loc.getBlockZ());
+                             loc.getBlockX() + ", " + loc.getBlockY() + ", " + loc.getBlockZ() + suppressed);
         }
     }
 
+    // ------------------------------------------------------------------------
+    /**
+     * Return true if the crystal is in a position that can be used to summon
+     * the dragon.
+     *
+     * When summoning the dragon, players can break the crystals on the frame
+     * before the dragon CreatureSpawnEvent (reason DEFAULT) occurs, and
+     * potentially recover them, if they don't burn up in the fire underneath.
+     * This method is used to detect that situation and prevent recovery of the
+     * crystals.
+     *
+     * Getting delicate about the exact coordinates of the crystal won't work
+     * because a determined player will move the crystals with pistons
+     * (verified). Any crystals too close to the portal would normally be blown
+     * up by the explosion when the dragon spawns, anyway.
+     *
+     * @param loc the location of the crystal.
+     * @return true if the crystal is in a position that can be used to summon
+     *         the dragon.
+     */
+    protected boolean isDragonSpawningCrystal(Location loc) {
+        return (loc.distance(CONFIG.END_PORTAL_LOCATION) < CONFIG.END_PORTAL_RADIUS);
+    }
+
     // ------------------------------------------------------------------------
     /**
      * Reference to WorldGuard.