Initial version.

.gitignore

@@ -10,3 +10,11 @@
 
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
+
+# Eclipse
+.classpath
+.project
+.settings
+classes
+bin
+

README.md

@@ -1,2 +1,6 @@
-# SafeCrystals
+SafeCrystals
+------------
 Prevent Ender Crystals from exploding and breaking blocks or damaging entities.
+
+Players who can build in a region can break the crystals causing them to drop
+as an item.  That event is recorded in the server log.

plugin.yml

@@ -0,0 +1,14 @@
+name: ${project.name}
+version: ${project.version}
+author: totemo
+authors: [totemo]
+description: ${project.description}
+website: ${project.url}
+main: nu.nerd.safecrystals.SafeCrystals
+
+depend: [WorldGuard]
+
+permissions: {}
+
+commands: {}
+

pom.xml

@@ -0,0 +1,79 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>nu.nerd</groupId>
+	<name>SafeCrystals</name>
+	<artifactId>${project.name}</artifactId>
+	<version>0.1.0</version>
+	<packaging>jar</packaging>
+	<description>Prevent Ender Crystals from exploding and breaking blocks or damaging entities.</description>
+	<url>https://github.com/totemo/${project.name}</url>
+	<scm>
+		<connection>scm:git:git://github.com/NerdNu/${project.name}.git</connection>
+		<url>https://github.com/NerdNu/${project.name}</url>
+		<developerConnection>scm:git:git://github.com/NerdNu/${project.name}.git</developerConnection>
+	</scm>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	</properties>
+	<repositories>
+		<repository>
+			<id>spigot-repo</id>
+			<url>https://hub.spigotmc.org/nexus/content/groups/public/</url>
+		</repository>
+		<repository>
+			<id>sk89q-repo</id>
+			<url>http://maven.sk89q.com/repo/</url>
+		</repository>
+	</repositories>
+	<dependencies>
+		<dependency>
+			<groupId>org.spigotmc</groupId>
+			<artifactId>spigot-api</artifactId>
+			<version>1.9-R0.1-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>com.sk89q</groupId>
+			<artifactId>worldguard</artifactId>
+			<version>6.0.0-SNAPSHOT</version>
+		</dependency>
+	</dependencies>
+	<build>
+		<defaultGoal>clean package</defaultGoal>
+		<sourceDirectory>${basedir}/src</sourceDirectory>
+		<resources>
+			<resource>
+				<targetPath>.</targetPath>
+				<filtering>true</filtering>
+				<directory>${basedir}</directory>
+				<includes>
+					<include>plugin.yml</include>
+				</includes>
+			</resource>
+		</resources>
+		<pluginManagement>
+			<plugins>
+				<plugin>
+					<groupId>org.apache.maven.plugins</groupId>
+					<artifactId>maven-jar-plugin</artifactId>
+					<version>2.1</version>
+					<configuration>
+						<archive>
+							<addMavenDescriptor>false</addMavenDescriptor>
+						</archive>
+						<finalName>${project.artifactId}-${project.version}</finalName>
+					</configuration>
+				</plugin>
+				<plugin>
+					<groupId>org.apache.maven.plugins</groupId>
+					<artifactId>maven-compiler-plugin</artifactId>
+					<version>2.0.2</version>
+					<configuration>
+						<source>1.7</source>
+						<target>1.7</target>
+					</configuration>
+				</plugin>
+			</plugins>
+		</pluginManagement>
+	</build>
+</project>

src/nu/nerd/safecrystals/SafeCrystals.java

@@ -0,0 +1,125 @@
+package nu.nerd.safecrystals;
+
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.EntityType;
+import org.bukkit.entity.Player;
+import org.bukkit.entity.Projectile;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.entity.EntityDamageByEntityEvent;
+import org.bukkit.event.entity.EntityExplodeEvent;
+import org.bukkit.event.player.PlayerInteractEvent;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.plugin.java.JavaPlugin;
+
+import com.sk89q.worldguard.bukkit.WorldGuardPlugin;
+
+// ----------------------------------------------------------------------------
+/**
+ * Prevent Ender Crystals from exploding and breaking blocks or damaging
+ * entities.
+ *
+ * Players who have permission to build in a WorldGuard region can break the
+ * crystals into dropped items.
+ *
+ * WorldGuard build permission is checked before allowing a player to place an
+ * Ender Crystal in a region.
+ */
+public class SafeCrystals extends JavaPlugin implements Listener {
+
+    // ------------------------------------------------------------------------
+    /**
+     * @see org.bukkit.plugin.java.JavaPlugin#onEnable()
+     */
+    @Override
+    public void onEnable() {
+        _worldGuard = (WorldGuardPlugin) getServer().getPluginManager().getPlugin("WorldGuard");
+        Bukkit.getPluginManager().registerEvents(this, this);
+    }
+
+    // ------------------------------------------------------------------------
+    /**
+     * Prevent Ender Crystals from exploding.
+     *
+     * Remove and drop as item when appropriate.
+     */
+    @EventHandler(ignoreCancelled = true)
+    public void onEntityExplode(EntityExplodeEvent event) {
+        Entity entity = event.getEntity();
+        if (entity.getType() == EntityType.ENDER_CRYSTAL) {
+            event.setCancelled(true);
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    /**
+     * Prevent Ender Crystals from being damaged by other entities.
+     *
+     * If the damager is a player who can build, drop the crystal as an item.
+     * Projectiles are handled the same as the player who shot them.
+     */
+    @EventHandler()
+    public void onEntityDamageByEntity(EntityDamageByEntityEvent event) {
+        Entity entity = event.getEntity();
+        if (entity.getType() == EntityType.ENDER_CRYSTAL) {
+            event.setCancelled(true);
+
+            if (event.getDamager() instanceof Player) {
+                tryBreakEnderCrystal(entity, (Player) event.getDamager());
+            } else if (event.getDamager() instanceof Projectile) {
+                Projectile projectile = (Projectile) event.getDamager();
+                if (projectile.getShooter() instanceof Player) {
+                    tryBreakEnderCrystal(entity, (Player) projectile.getShooter());
+                }
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    /**
+     * Check that a player can build before placing an Ender Crystal.
+     *
+     * Minecraft will place an Ender Crystal on top of obsidian or bedrock even
+     * when the player clicks the sides or underside of the block. Therefore, we
+     * always check build permissions <i>above</i> the clicked block.
+     */
+    @EventHandler()
+    public void onPlayerInteract(PlayerInteractEvent event) {
+        if (event.getMaterial() == Material.END_CRYSTAL && event.getAction() == Action.RIGHT_CLICK_BLOCK) {
+            Block destination = event.getClickedBlock().getRelative(BlockFace.UP);
+            if (!_worldGuard.canBuild(event.getPlayer(), destination.getLocation())) {
+                event.setCancelled(true);
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    /**
+     * Handle a specific player's attempt to can break an Ender Crystal.
+     *
+     * @param crystal the crystal.
+     * @param player the player.
+     */
+    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));
+            getLogger().info(player.getName() + " broke an Ender Crystal at " +
+                             loc.getWorld().getName() + ", " +
+                             loc.getBlockX() + ", " + loc.getBlockY() + ", " + loc.getBlockZ());
+        }
+    }
+
+    // ------------------------------------------------------------------------
+    /**
+     * Reference to WorldGuard.
+     */
+    protected WorldGuardPlugin _worldGuard;
+} // class SafeCrystals