Annotations for the storage api

src/main/java/net/minestom/server/storage/StorageLocation.java

@@ -5,6 +5,8 @@ import net.minestom.server.data.*;
 import net.minestom.server.utils.binary.BinaryReader;
 import net.minestom.server.utils.binary.BinaryWriter;
 import net.minestom.server.utils.validate.Check;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -37,10 +39,11 @@ public class StorageLocation {
      * Gets the data associated with a key using {@link StorageSystem#get(String)}.
      *
      * @param key the key
-     * @return the data associated to {@code key}
+     * @return the data associated to {@code key}, null if not any
      * @see StorageSystem#get(String)
      */
-    public byte[] get(String key) {
+    @Nullable
+    public byte[] get(@NotNull String key) {
         return storageSystem.get(key);
     }
 
@@ -51,7 +54,7 @@ public class StorageLocation {
      * @param data the data
      * @see StorageSystem#set(String, byte[])
      */
-    public void set(String key, byte[] data) {
+    public void set(@NotNull String key, byte[] data) {
         this.storageSystem.set(key, data);
     }
 
@@ -61,7 +64,7 @@ public class StorageLocation {
      * @param key the key
      * @see StorageSystem#delete(String)
      */
-    public void delete(String key) {
+    public void delete(@NotNull String key) {
         this.storageSystem.delete(key);
     }
 
@@ -85,7 +88,7 @@ public class StorageLocation {
      * @param type   the class of the data
      * @param <T>    the type of the data
      */
-    public <T> void set(String key, T object, Class<T> type) {
+    public <T> void set(@NotNull String key, @NotNull T object, @NotNull Class<T> type) {
         final DataType<T> dataType = DATA_MANAGER.getDataType(type);
         Check.notNull(dataType, "You can only save registered DataType type!");
 
@@ -109,7 +112,7 @@ public class StorageLocation {
      * @param <T>  the type of the data
      * @return the object associated to the key
      */
-    public <T> T get(String key, Class<T> type) {
+    public <T> T get(@NotNull String key, @NotNull Class<T> type) {
         final DataType<T> dataType = DATA_MANAGER.getDataType(type);
         Check.notNull(dataType, "You can only get registered DataType type!");
 
@@ -123,7 +126,7 @@ public class StorageLocation {
         return dataType.decode(binaryReader);
     }
 
-    public <T> T getOrDefault(String key, Class<T> type, T defaultValue) {
+    public <T> T getOrDefault(@NotNull String key, @NotNull Class<T> type, @Nullable T defaultValue) {
         T value;
         return (value = get(key, type)) != null ? value : defaultValue;
     }
@@ -135,7 +138,7 @@ public class StorageLocation {
      * @param key           the key of the data
      * @param dataContainer the {@link DataContainer} which will contain the new data
      */
-    public void getAndCloneData(String key, DataContainer dataContainer) {
+    public void getAndCloneData(@NotNull String key, @NotNull DataContainer dataContainer) {
         synchronized (cachedData) {
             // Copy data from the cachedMap
             if (cachedData.containsKey(key)) {
@@ -161,7 +164,7 @@ public class StorageLocation {
      * @param key           the key of the data
      * @param dataContainer the {@link DataContainer} which will contain the new data
      */
-    public void getAndCacheData(String key, DataContainer dataContainer) {
+    public void getAndCacheData(@NotNull String key, @NotNull DataContainer dataContainer) {
         synchronized (cachedData) {
             // Give the cached SerializableData if already loaded
             if (cachedData.containsKey(key)) {
@@ -184,7 +187,7 @@ public class StorageLocation {
      *
      * @param key the specified cached data key
      */
-    public void saveAndRemoveCachedData(String key) {
+    public void saveAndRemoveCachedData(@NotNull String key) {
         synchronized (cachedData) {
             final SerializableData serializableData = cachedData.get(key);
             if (serializableData == null)
@@ -212,7 +215,7 @@ public class StorageLocation {
      *
      * @param key the data key
      */
-    public void saveCachedData(String key) {
+    public void saveCachedData(@NotNull String key) {
         synchronized (cachedData) {
             final SerializableData data = cachedData.get(key);
             set(key, data.getIndexedSerializedData());
@@ -226,6 +229,7 @@ public class StorageLocation {
      *
      * @return the location
      */
+    @NotNull
     public String getLocation() {
         return location;
     }

src/main/java/net/minestom/server/storage/StorageManager.java

@@ -1,6 +1,8 @@
 package net.minestom.server.storage;
 
 import net.minestom.server.utils.validate.Check;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -33,7 +35,7 @@ public final class StorageManager {
      * @param storageSystem  the {@link StorageSystem} used in the specified location
      * @return the specified {@link StorageLocation}
      */
-    public StorageLocation getLocation(String location, StorageOptions storageOptions, StorageSystem storageSystem) {
+    public StorageLocation getLocation(@NotNull String location, @NotNull StorageOptions storageOptions, @NotNull StorageSystem storageSystem) {
         Check.notNull(storageOptions, "The storage option cannot be null");
         return locationMap.computeIfAbsent(location,
                 s -> new StorageLocation(storageSystem, location, storageOptions));
@@ -48,7 +50,7 @@ public final class StorageManager {
      * @return the {@link StorageLocation} at {@code location} with the default {@link StorageSystem}
      * @throws NullPointerException if no default {@link StorageSystem} is defined with {@link #defineDefaultStorageSystem(Supplier)}
      */
-    public StorageLocation getLocation(String location, StorageOptions storageOptions) {
+    public StorageLocation getLocation(@NotNull String location, @NotNull StorageOptions storageOptions) {
         Check.notNull(defaultStorageSystemSupplier,
                 "You need to either define a default storage system or specify your storage system for this specific location");
         final StorageSystem storageSystem = defaultStorageSystemSupplier.get();
@@ -63,7 +65,8 @@ public final class StorageManager {
      * @return the {@link StorageLocation} at {@code location} with the default {@link StorageSystem}
      * @throws NullPointerException if no default StorageSystem is defined {@link #defineDefaultStorageSystem(Supplier)}
      */
-    public StorageLocation getLocation(String location) {
+    @Nullable
+    public StorageLocation getLocation(@NotNull String location) {
         return getLocation(location, new StorageOptions());
     }
 
@@ -74,7 +77,7 @@ public final class StorageManager {
      * @param storageSystem the {@link StorageSystem} to use
      * @return true if the location exists, false otherwise
      */
-    public boolean locationExists(String location, StorageSystem storageSystem) {
+    public boolean locationExists(@NotNull String location, @NotNull StorageSystem storageSystem) {
         return storageSystem.exists(location);
     }
 
@@ -84,7 +87,7 @@ public final class StorageManager {
      * @param location the location
      * @return true if the location exists
      */
-    public boolean locationExists(String location) {
+    public boolean locationExists(@NotNull String location) {
         return locationExists(location, defaultStorageSystemSupplier.get());
     }
 
@@ -94,6 +97,7 @@ public final class StorageManager {
      *
      * @return an unmodifiable list of all the loaded {@link StorageLocation}
      */
+    @NotNull
     public Collection<StorageLocation> getLoadedLocations() {
         return Collections.unmodifiableCollection(locationMap.values());
     }
@@ -103,7 +107,7 @@ public final class StorageManager {
      *
      * @param storageSystemSupplier the supplier called to get the default {@link StorageSystem}
      */
-    public void defineDefaultStorageSystem(Supplier<StorageSystem> storageSystemSupplier) {
+    public void defineDefaultStorageSystem(@NotNull Supplier<StorageSystem> storageSystemSupplier) {
         if (this.defaultStorageSystemSupplier != null) {
             LOGGER.warn("The default storage-system has been changed. This could lead to issues!");
         }

src/main/java/net/minestom/server/storage/StorageSystem.java

@@ -1,5 +1,8 @@
 package net.minestom.server.storage;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 /**
  * Represents a way of storing data by key/value.
  * The location does not have to be a file or folder path. It is the 'identifier' of the data location.
@@ -12,7 +15,7 @@ public interface StorageSystem {
      * @param location the location
      * @return true if the location exists
      */
-    boolean exists(String location);
+    boolean exists(@NotNull String location);
 
     /**
      * Called when a {@link StorageLocation} is opened with this {@link StorageSystem}.
@@ -20,15 +23,16 @@ public interface StorageSystem {
      * @param location       the location name
      * @param storageOptions the {@link StorageOptions}
      */
-    void open(String location, StorageOptions storageOptions);
+    void open(@NotNull String location, @NotNull StorageOptions storageOptions);
 
     /**
      * Gets the data associated to a key.
      *
      * @param key the key to retrieve
-     * @return the retrieved data
+     * @return the retrieved data, null if the data doesn't exist
      */
-    byte[] get(String key);
+    @Nullable
+    byte[] get(@NotNull String key);
 
     /**
      * Sets the specified data to the defined key.
@@ -36,14 +40,14 @@ public interface StorageSystem {
      * @param key  the key of the data
      * @param data the data
      */
-    void set(String key, byte[] data);
+    void set(@NotNull String key, byte[] data);
 
     /**
      * Deletes the specified key from the database.
      *
      * @param key the key to delete
      */
-    void delete(String key);
+    void delete(@NotNull String key);
 
     /**
      * Called when the location is closed, generally during server shutdown.

src/main/java/net/minestom/server/storage/systems/FileStorageSystem.java

@@ -2,6 +2,7 @@ package net.minestom.server.storage.systems;
 
 import net.minestom.server.storage.StorageOptions;
 import net.minestom.server.storage.StorageSystem;
+import org.jetbrains.annotations.NotNull;
 import org.rocksdb.*;
 
 import java.nio.file.Files;
@@ -24,12 +25,12 @@ public class FileStorageSystem implements StorageSystem {
     private RocksDB rocksDB;
 
     @Override
-    public boolean exists(String location) {
+    public boolean exists(@NotNull String location) {
         return Files.isDirectory(Paths.get(location));
     }
 
     @Override
-    public void open(String location, StorageOptions storageOptions) {
+    public void open(@NotNull String location, @NotNull StorageOptions storageOptions) {
         Options options = new Options().setCreateIfMissing(true);
 
         if (storageOptions.hasCompression()) {
@@ -45,7 +46,7 @@ public class FileStorageSystem implements StorageSystem {
     }
 
     @Override
-    public byte[] get(String key) {
+    public byte[] get(@NotNull String key) {
         try {
             return rocksDB.get(getKey(key));
         } catch (RocksDBException e) {
@@ -55,7 +56,7 @@ public class FileStorageSystem implements StorageSystem {
     }
 
     @Override
-    public void set(String key, byte[] data) {
+    public void set(@NotNull String key, byte[] data) {
         try {
             this.rocksDB.put(getKey(key), data);
         } catch (RocksDBException e) {
@@ -64,7 +65,7 @@ public class FileStorageSystem implements StorageSystem {
     }
 
     @Override
-    public void delete(String key) {
+    public void delete(@NotNull String key) {
         try {
             this.rocksDB.delete(getKey(key));
         } catch (RocksDBException e) {