blub

.gitignore

@@ -0,0 +1 @@
+/target/

src/main/java/de/welterde/em/Entity.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em;
+
+/**
+ *
+ * @author welterde
+ */
+public abstract class Entity {
+    protected final EntityStorage ctx;
+    protected final int id;
+        
+    public Entity(EntityStorage ctx, int id) {
+        this.id = id;
+        this.ctx = ctx;
+    }
+    
+    public int getEntityId() {
+        return this.id;
+    }
+}

src/main/java/de/welterde/em/EntityRef.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em;
+
+import java.lang.ref.WeakReference;
+
+/**
+ *
+ * @author welterde
+ * @param <X>
+ */
+public class EntityRef<X extends Entity> {
+    protected final EntityStorage ctx;
+    
+    protected WeakReference<X> ref;
+    protected final int entityId;
+    protected boolean invalid;
+    
+    public EntityRef(EntityStorage ctx, X entity) {
+        this.ctx = ctx;
+        this.entityId = entity.getEntityId();
+        this.invalid = false;
+    }
+    
+    public X get() {
+        if(this.invalid)
+            throw new InvalidEntityReference(this.entityId);
+        
+        var e = this.ref.get();
+        if(e != null)
+            return e;
+        
+        synchronized(this) {
+            var ee = this.ctx.getEntity(this.entityId);
+            // check if entity was already destroyed
+            if (ee == null) {
+                this.invalid = true;
+                throw new InvalidEntityReference(this.entityId);
+            }
+            
+            // try to cast it to the correct type and since we do not reuse
+            // entity ids this should not go wrong, but maybe it did..
+            try {
+                X eee = (X) ee;
+                this.ref = new WeakReference(eee);
+                return eee;
+            } catch(ClassCastException exc) {
+                this.invalid = true;
+                throw new InvalidEntityReference(this.entityId);
+            }
+        }
+    }
+}

src/main/java/de/welterde/em/EntityStorage.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em;
+
+/**
+ *
+ * @author welterde
+ */
+public interface EntityStorage {
+    public Entity getEntity(int entityId);
+}

src/main/java/de/welterde/em/InvalidEntityReference.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em;
+
+/**
+ *
+ * @author welterde
+ */
+public class InvalidEntityReference extends RuntimeException {
+
+    /**
+     * Creates a new instance of <code>InvalidEntityReference</code> without
+     * detail message.
+     */
+    public InvalidEntityReference() {
+    }
+
+    /**
+     * Constructs an instance of <code>InvalidEntityReference</code> with the
+     * specified detail message.
+     *
+     * @param msg the detail message.
+     */
+    public InvalidEntityReference(int eid) {
+        super("Invalid entity reference to entity=" + eid);
+    }
+}

src/main/java/de/welterde/em/data/CounterName.java

@@ -21,6 +21,9 @@ package de.welterde.em.data;
  * @author welterde
  */
 public enum CounterName {
+    COUNTRY_IDX,
+    DIMENSION_IDX,
+    AREA_IDX,
     LOCATION_IDX,
     ENTITY_IDX,
 }

src/main/java/de/welterde/em/data/Entity.java

@@ -37,6 +37,12 @@ public interface Entity {
      */
     public Location getLocation();
     
+    /**
+     * Relative position within location
+     * @return 
+     */
+    public LocationPos getLocationPos();
+    
     public boolean isMovable();
     
     public MovementStatus getMovementStatus();

src/main/java/de/welterde/em/data/LocationPos.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em.data;
+
+/**
+ *
+ * @author welterde
+ */
+public interface LocationPos {
+    
+}

src/main/java/de/welterde/em/w/Area.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em.w;
+
+import de.welterde.em.data.Location;
+import de.welterde.em.data.TerrainGen;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+/**
+ *
+ * @author welterde
+ */
+public class Area {
+    protected final int id;
+    protected final ReadWriteLock structLock;
+    
+    protected final AreaMap map;
+    protected final Map<Integer, Location> locations;
+    
+    public Area(int id, TerrainGen gen) {
+        this.id = id;
+        this.structLock = new ReentrantReadWriteLock();
+        
+        this.map = new AreaMap(gen);
+        this.locations = new HashMap<>();
+    }
+}

src/main/java/de/welterde/em/w/AreaMap.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em.w;
+
+import de.welterde.em.data.MapCoord;
+import de.welterde.em.data.TerrainGen;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+/**
+ *
+ * @author welterde
+ */
+public class AreaMap {
+    protected final Map<MapCoord, Block> blockMap;
+    protected final TerrainGen gen;
+    protected final ReadWriteLock structLock;
+    
+    public AreaMap(TerrainGen gen) {
+        this.gen = gen;
+        this.blockMap = new HashMap<>();
+        this.structLock = new ReentrantReadWriteLock();
+    }
+    
+    public Block getBlock(MapCoord c) {
+        if(!this.blockMap.containsKey(c)) {
+            // default to the terrain generator
+            return this.gen.generateBlock(this, c);
+        } else {
+            return this.tiles.get(c);
+        }
+    }
+}

src/main/java/de/welterde/em/w/Block.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em.w;
+
+/**
+ * 5m x 5m block of the world
+ * @author welterde
+ */
+public class Block {
+    
+}

src/main/java/de/welterde/em/w/BlockCoord.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2026 welterde
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package de.welterde.em.w;
+
+/**
+ *
+ * @author welterde
+ */
+class BlockCoord {
+    
+}

src/main/java/de/welterde/em/w/Country.java

@@ -16,10 +16,17 @@
  */
 package de.welterde.em.w;
 
+import de.welterde.em.Entity;
+import de.welterde.em.EntityStorage;
+
 /**
  *
  * @author welterde
  */
-public class Country {
+public class Country  extends Entity {
+    
+    public Country(EntityStorage ctx, int id) {
+        super(ctx, id);
+    }
     
 }

src/main/java/de/welterde/em/w/Dimension.java

@@ -16,10 +16,39 @@
  */
 package de.welterde.em.w;
 
+import de.welterde.em.Entity;
+import de.welterde.em.data.CounterName;
+import de.welterde.em.data.TerrainGen;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
 /**
  *
  * @author welterde
  */
-public class Dimension {
+public class Dimension extends Entity {
+    protected final ReadWriteLock structLock;
     
+    protected final Map<Integer, Area> areas;
+    
+    public Dimension(World ctx, int id) {
+        super(ctx, id);
+        this.structLock = new ReentrantReadWriteLock();
+        
+        this.areas = new HashMap<>();
+    }
+    
+    public Area addArea(TerrainGen gen) {
+        this.structLock.writeLock().lock();
+        try {
+            var areaId = this.ctx.allocateId(CounterName.AREA_IDX);
+            var area = new Area(areaId, gen);
+            this.areas.put(areaId, area);
+            return area;
+        } finally {
+            this.structLock.writeLock().unlock();
+        }
+    }
 }

src/main/java/de/welterde/em/w/World.java

@@ -16,10 +16,72 @@
  */
 package de.welterde.em.w;
 
+import de.welterde.em.Entity;
+import de.welterde.em.EntityRef;
+import de.welterde.em.EntityStorage;
+import de.welterde.em.data.CounterName;
+import java.util.ArrayList;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
 /**
  *
  * @author welterde
  */
-public class World {
+public class World implements EntityStorage {
+    protected final ArrayList<Entity> entities;
+    protected final EnumMap<CounterName, Integer> counters;
+    protected final ArrayList<EntityRef<Dimension>> dimensions;
+    protected final Map<Integer, EntityRef<Country>> countries;
+    protected final ReadWriteLock structLock;
     
+    public World() {
+        this.counters = new EnumMap<>(CounterName.class);
+        this.dimensions = new ArrayList<>();
+        this.countries = new HashMap<>();
+        this.entities = new ArrayList<>();
+        
+        this.structLock = new ReentrantReadWriteLock();
+    }
+    
+    
+    public int allocateId(CounterName name) {
+        synchronized(this.counters) {
+            // start counter at zero if not yet a thing
+            if(!this.counters.containsKey(name))
+                this.counters.put(name, 0);
+            
+            var nextVal = this.counters.get(name) + 1;
+            this.counters.put(name, nextVal);
+            return nextVal;
+        }
+    }
+    
+    public Dimension addDimension() {
+        this.structLock.writeLock().lock();
+        try{
+            var dim = new Dimension(this, this.dimensions.size());
+            this.dimensions.add(dim);
+            return dim;
+        } finally {
+            this.structLock.writeLock().unlock();
+        }
+    }
+    public Dimension getDimension(int id) {
+        this.structLock.readLock().lock();
+        try {
+            return this.dimensions.get(id);
+        } finally {
+            this.structLock.readLock().unlock();
+        }
+    }
+
+    @Override
+    public Entity getEntity(int entityId) {
+        return this.entities.get(entityId);
+    }
 }