Implement persistent data

src/dev/w1zzrd/invtweaks/DataStore.java

@@ -0,0 +1,62 @@
+package dev.w1zzrd.invtweaks;
+
+import org.bukkit.Bukkit;
+import org.bukkit.configuration.InvalidConfigurationException;
+import org.bukkit.configuration.file.FileConfiguration;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.configuration.serialization.ConfigurationSerializable;
+import org.bukkit.plugin.Plugin;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class DataStore {
+
+    private static final Logger logger = Bukkit.getLogger();
+
+    private final File storeFile;
+    private final FileConfiguration config;
+
+    public DataStore(final String storeName, final Plugin plugin) {
+        storeFile = new File(plugin.getDataFolder(), storeName + ".yml");
+        config = YamlConfiguration.loadConfiguration(storeFile);
+
+        // Save config in case it doesn't exist
+        saveData();
+    }
+
+    public <T extends ConfigurationSerializable> T loadData(final String path, final DefaultGetter<T> defaultValue) {
+        final T value = (T) config.get(path);
+        return value == null ? defaultValue.get() : value;
+    }
+
+    public <T extends ConfigurationSerializable> void storeData(final String path, final T value) {
+        config.set(path, value);
+    }
+
+    public void saveData() {
+        try {
+            config.save(storeFile);
+        } catch (IOException e) {
+            logger.log(Level.SEVERE, Logger.GLOBAL_LOGGER_NAME + " Could not save data due to an I/O error", e);
+        }
+    }
+
+    public void loadData() {
+        try {
+            config.load(storeFile);
+        } catch (IOException | InvalidConfigurationException e) {
+            logger.log(Level.SEVERE, Logger.GLOBAL_LOGGER_NAME + " Could not load data due to an I/O error", e);
+        }
+    }
+
+    /**
+     * Functional interface for constructing default values
+     * @param <T> Type to construct
+     */
+    public interface DefaultGetter<T> {
+        T get();
+    }
+}

src/dev/w1zzrd/invtweaks/serialization/UUIDList.java

@@ -0,0 +1,30 @@
+package dev.w1zzrd.invtweaks.serialization;
+
+import org.bukkit.configuration.serialization.ConfigurationSerializable;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class UUIDList implements ConfigurationSerializable {
+
+    public final List<UUID> uuids;
+
+    public UUIDList(final List<UUID> backingList) {
+        uuids = backingList;
+    }
+
+    public UUIDList() {
+        this(new ArrayList<>());
+    }
+
+    public UUIDList(final Map<String, Object> values) {
+        this();
+        if (values.containsKey("values"))
+            uuids.addAll(((Collection<String>)values.get("values")).stream().map(UUID::fromString).collect(Collectors.toSet()));
+    }
+
+    @Override
+    public Map<String, Object> serialize() {
+        return Collections.singletonMap("values", uuids.stream().map(UUID::toString).collect(Collectors.toList()));
+    }
+}