Added Redstone event support for detector rails.

src/main/java/net/minecraft/server/BlockMinecartDetector.java

@@ -0,0 +1,101 @@
+package net.minecraft.server;
+
+import java.util.List;
+import java.util.Random;
+
+// CraftBukkit start
+import org.bukkit.Bukkit;
+import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.block.Action;
+import org.bukkit.event.block.BlockRedstoneEvent;
+// CraftBukkit end
+
+public class BlockMinecartDetector extends BlockMinecartTrack {
+
+    public BlockMinecartDetector(int i, int j) {
+        super(i, j, true);
+        this.a(true);
+    }
+
+    public int c() {
+        return 20;
+    }
+
+    public boolean isPowerSource() {
+        return true;
+    }
+
+    public void a(World world, int i, int j, int k, Entity entity) {
+        if (!world.isStatic) {
+            int l = world.getData(i, j, k);
+
+            if ((l & 8) == 0) {
+                this.g(world, i, j, k, l);
+            }
+        }
+    }
+
+    public void a(World world, int i, int j, int k, Random random) {
+        if (!world.isStatic) {
+            int l = world.getData(i, j, k);
+
+            if ((l & 8) != 0) {
+                this.g(world, i, j, k, l);
+            }
+        }
+    }
+
+    public boolean a(IBlockAccess iblockaccess, int i, int j, int k, int l) {
+        return (iblockaccess.getData(i, j, k) & 8) != 0;
+    }
+
+    public boolean c(World world, int i, int j, int k, int l) {
+        return (world.getData(i, j, k) & 8) == 0 ? false : l == 1;
+    }
+
+    private void g(World world, int i, int j, int k, int l) {
+        boolean flag = (l & 8) != 0;
+        boolean flag1 = false;
+        float f = 0.125F;
+        List list = world.a(EntityMinecart.class, AxisAlignedBB.b((double) ((float) i + f), (double) j, (double) ((float) k + f), (double) ((float) (i + 1) - f), (double) j + 0.25D, (double) ((float) (k + 1) - f)));
+
+        if (list.size() > 0) {
+            flag1 = true;
+        }
+
+        // CraftBukkit start
+        if (flag != flag1) {
+            CraftServer server = world.getServer();
+            CraftWorld craftWorld = world.getWorld();
+            CraftBlock block = (CraftBlock) craftWorld.getBlockAt(i, j, k);
+
+            BlockRedstoneEvent eventRedstone = new BlockRedstoneEvent(block, flag ? 1 : 0, flag1 ? 1 : 0);
+            server.getPluginManager().callEvent(eventRedstone);
+
+            flag1 = eventRedstone.getNewCurrent() > 0;
+        }
+        // CraftBukkit end
+
+        if (flag1 && !flag) {
+            world.setData(i, j, k, l | 8);
+            world.applyPhysics(i, j, k, this.id);
+            world.applyPhysics(i, j - 1, k, this.id);
+            world.b(i, j, k, i, j, k);
+        }
+
+        if (!flag1 && flag) {
+            world.setData(i, j, k, l & 7);
+            world.applyPhysics(i, j, k, this.id);
+            world.applyPhysics(i, j - 1, k, this.id);
+            world.b(i, j, k, i, j, k);
+        }
+
+        if (flag1) {
+            world.c(i, j, k, this.id, this.c());
+        }
+    }
+}