From b54c7ad6624d430a0bd27077411fa75a2b54d24d Mon Sep 17 00:00:00 2001
From: Florian CUNY <poslovitch@gmail.com>
Date: Mon, 13 Aug 2018 21:45:43 +0200
Subject: [PATCH] Rewrote IslandGrid to use Table<> from Guava

It also prepares further implementation for reserved "locations"
---
 .../bentobox/managers/island/IslandGrid.java  | 92 +++++++++++--------
 1 file changed, 53 insertions(+), 39 deletions(-)

diff --git a/src/main/java/world/bentobox/bentobox/managers/island/IslandGrid.java b/src/main/java/world/bentobox/bentobox/managers/island/IslandGrid.java
index 3a002c191..08cbbc247 100644
--- a/src/main/java/world/bentobox/bentobox/managers/island/IslandGrid.java
+++ b/src/main/java/world/bentobox/bentobox/managers/island/IslandGrid.java
@@ -1,17 +1,21 @@
 package world.bentobox.bentobox.managers.island;
 
-import java.util.Map.Entry;
-import java.util.TreeMap;
-
+import com.google.common.collect.Table;
+import com.google.common.collect.TreeBasedTable;
 import world.bentobox.bentobox.database.objects.Island;
 
 /**
- * Handles the island location grid for each world
+ * Handles the island location grid for each world.
  * @author tastybento
- *
  */
 public class IslandGrid {
-    private TreeMap<Integer, TreeMap<Integer, Island>> grid = new TreeMap<>();
+
+    /**
+     * Row : x location
+     * Column : z location
+     * Value : Island
+     */
+    private Table<Integer, Integer, Cell> grid = TreeBasedTable.create();
 
     /**
      * Adds island to grid
@@ -19,21 +23,13 @@ public class IslandGrid {
      * @return true if successfully added, false if island already exists, or there is an overlap
      */
     public boolean addToGrid(Island island) {
-        if (grid.containsKey(island.getMinX())) {
-            TreeMap<Integer, Island> zEntry = grid.get(island.getMinX());
-            if (zEntry.containsKey(island.getMinZ())) {
-                return false;
-            } else {
-                // Add island
-                zEntry.put(island.getMinZ(), island);
-                grid.put(island.getMinX(), zEntry);
-            }
-        } else {
-            // Add island
-            TreeMap<Integer, Island> zEntry = new TreeMap<>();
-            zEntry.put(island.getMinZ(), island);
-            grid.put(island.getMinX(), zEntry);
+        if (grid.contains(island.getMinX(), island.getMinZ())) {
+            // It is either occupied or reserved, so return false
+            return false;
         }
+
+        // All clear, add the island to the grid.
+        grid.put(island.getMinX(), island.getMinZ(), new Cell(CellState.OCCUPIED, island));
         return true;
     }
     
@@ -45,16 +41,10 @@ public class IslandGrid {
     public boolean removeFromGrid(Island island) {
         // Remove from grid
         if (island != null) {
-            int x = island.getMinX();
-            int z = island.getMinZ();
-            if (grid.containsKey(x)) {
-                TreeMap<Integer, Island> zEntry = grid.get(x);
-                if (zEntry.containsKey(z)) {
-                    // Island exists - delete it
-                    zEntry.remove(z);
-                    grid.put(x, zEntry);
-                    return true;
-                }
+            if (grid.contains(island.getMinX(), island.getMinZ())) {
+                // TODO add support for RESERVED cells
+                grid.remove(island.getMinX(), island.getMinZ());
+                return true;
             }
         }
         return false;
@@ -69,17 +59,41 @@ public class IslandGrid {
      * @return Island or null
      */
     public Island getIslandAt(int x, int z) {
-        Entry<Integer, TreeMap<Integer, Island>> en = grid.floorEntry(x);
-        if (en != null) {
-            Entry<Integer, Island> ent = en.getValue().floorEntry(z);
-            if (ent != null) {
-                // Check if in the island range
-                Island island = ent.getValue();
-                if (island.inIslandSpace(x, z)) {
-                    return island;
-                }
+        if (grid.contains(x, z)) {
+            Cell cell = grid.get(x, z);
+            if (cell.getState().equals(CellState.OCCUPIED)) {
+                return (Island) cell.getObject();
             }
         }
         return null;
     }
+
+    /**
+     * @author Poslovitch
+     */
+    private class Cell {
+        private CellState state;
+        private Object object;
+
+        private Cell(CellState state, Object object) {
+            this.state = state;
+            this.object = object;
+        }
+
+        private CellState getState() {
+            return state;
+        }
+
+        private Object getObject() {
+            return object;
+        }
+    }
+
+    /**
+     * @author Poslovitch
+     */
+    private enum CellState {
+        RESERVED,
+        OCCUPIED
+    }
 }