add simple file storage for objects

src/main/java/com/songoda/core/configuration/Config.java

@@ -126,16 +126,18 @@ public class Config extends ConfigSection {
         fileName = file;
     }
 
-    public Config(@NotNull Plugin plugin, @NotNull String directory, @NotNull String file) {
+    public Config(@NotNull Plugin plugin, @Nullable String directory, @NotNull String file) {
         this.plugin = plugin;
         dirName = directory;
         fileName = file;
     }
 
+    @NotNull
     public ConfigFileConfigurationAdapter getFileConfig() {
         return config;
     }
 
+    @NotNull
     public File getFile() {
         if (file == null) {
             if (dirName != null) {
@@ -175,6 +177,7 @@ public class Config extends ConfigSection {
      * @param autosaveInterval time in seconds
      * @return this class
      */
+    @NotNull
     public Config setAutosaveInterval(int autosaveInterval) {
         this.autosaveInterval = autosaveInterval;
         return this;
@@ -202,6 +205,7 @@ public class Config extends ConfigSection {
     /**
      * Default comment applied to config nodes
      */
+    @Nullable
     public ConfigFormattingRules.CommentStyle getDefaultNodeCommentFormat() {
         return defaultNodeCommentFormat;
     }
@@ -211,7 +215,8 @@ public class Config extends ConfigSection {
      * 
      * @return this config
      */
-    public Config setDefaultNodeCommentFormat(ConfigFormattingRules.CommentStyle defaultNodeCommentFormat) {
+    @NotNull
+    public Config setDefaultNodeCommentFormat(@Nullable ConfigFormattingRules.CommentStyle defaultNodeCommentFormat) {
         this.defaultNodeCommentFormat = defaultNodeCommentFormat;
         return this;
     }
@@ -219,6 +224,7 @@ public class Config extends ConfigSection {
     /**
      * Default comment applied to section nodes
      */
+    @Nullable
     public ConfigFormattingRules.CommentStyle getDefaultSectionCommentFormat() {
         return defaultSectionCommentFormat;
     }
@@ -228,7 +234,8 @@ public class Config extends ConfigSection {
      * 
      * @return this config
      */
-    public Config setDefaultSectionCommentFormat(ConfigFormattingRules.CommentStyle defaultSectionCommentFormat) {
+    @NotNull
+    public Config setDefaultSectionCommentFormat(@Nullable ConfigFormattingRules.CommentStyle defaultSectionCommentFormat) {
         this.defaultSectionCommentFormat = defaultSectionCommentFormat;
         return this;
     }
@@ -245,6 +252,7 @@ public class Config extends ConfigSection {
      * 
      * @return this config
      */
+    @NotNull
     public Config setRootNodeSpacing(int rootNodeSpacing) {
         this.rootNodeSpacing = rootNodeSpacing;
         return this;
@@ -264,6 +272,7 @@ public class Config extends ConfigSection {
      * 
      * @return this config
      */
+    @NotNull
     public Config setCommentSpacing(int commentSpacing) {
         this.commentSpacing = commentSpacing;
         return this;

src/main/java/com/songoda/core/configuration/DataStoreObject.java

@@ -0,0 +1,35 @@
+package com.songoda.core.configuration;
+
+import org.bukkit.configuration.ConfigurationSection;
+
+public interface DataStoreObject<T> {
+
+    /**
+     * @return a unique hashable instance of T to store this value under
+     */
+    public abstract T getKey();
+
+    /**
+     * @return a unique identifier for saving this value with
+     */
+    public abstract String getConfigKey();
+
+    /**
+     * Save this data to a ConfigurationSection
+     *
+     * @param sec
+     */
+    public abstract void saveToSection(ConfigurationSection sec);
+
+    /**
+     * @return true if this data has changed from the state saved to file
+     */
+    public boolean hasChanged();
+
+    /**
+     * Mark this data as needing a save or not
+     *
+     * @param isChanged
+     */
+    public void setChanged(boolean isChanged);
+}

src/main/java/com/songoda/core/configuration/SimpleDataStore.java

@@ -0,0 +1,220 @@
+package com.songoda.core.configuration;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.function.Function;
+import java.util.logging.Level;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.InvalidConfigurationException;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.plugin.Plugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Used to easily store a set of one data value
+ *
+ * @param <K> Key value that DataObject class uses to uniquely identify values
+ * @param <T> DataObject class that is used to store the data
+ * @since 2019-09-06
+ * @author jascotty2
+ */
+public class SimpleDataStore<K, T extends DataStoreObject<K>> {
+
+    protected final Plugin plugin;
+    protected final String filename, dirName;
+    private final Function<ConfigurationSection, T> getFromSection;
+    protected final HashMap<K, T> data = new HashMap();
+    private File file;
+    private final Object lock = new Object();
+    SaveTask saveTask;
+    Timer autosaveTimer;
+    /**
+     * time in seconds to start a save after a change is made
+     */
+    int autosaveInterval = 60;
+
+    public SimpleDataStore(@NotNull Plugin plugin, @NotNull String filename, Function<ConfigurationSection, T> loadFunction) {
+        this.plugin = plugin;
+        this.filename = filename;
+        dirName = null;
+        this.getFromSection = loadFunction;
+    }
+
+    public SimpleDataStore(@NotNull Plugin plugin, @Nullable String directory, @NotNull String filename, @NotNull Function<ConfigurationSection, T> loadFunction) {
+        this.plugin = plugin;
+        this.filename = filename;
+        this.dirName = directory;
+        this.getFromSection = loadFunction;
+    }
+
+    @NotNull
+    public File getFile() {
+        if (file == null) {
+            if (dirName != null) {
+                this.file = new File(plugin.getDataFolder() + dirName, filename != null ? filename : "data.yml");
+            } else {
+                this.file = new File(plugin.getDataFolder(), filename != null ? filename : "data.yml");
+            }
+        }
+        return file;
+    }
+
+    /**
+     * @return a directly-modifiable instance of the data mapping for this storage
+     */
+    public Map<K, T> getData() {
+        return data;
+    }
+
+    /**
+     * Returns the value to which the specified key is mapped,
+     * or {@code null} if this map contains no mapping for the key.
+     *
+     * @param key key whose mapping is to be retrieved from this storage
+     * @return the value associated with <tt>key</tt>, or
+     * <tt>null</tt> if there was no mapping for <tt>key</tt>.
+     */
+    @Nullable
+    public T get(K key) {
+        return data.get(key);
+    }
+
+    /**
+     * Removes the mapping for the specified key from this storage if present.
+     *
+     * @param key key whose mapping is to be removed from this storage
+     * @return the previous value associated with <tt>key</tt>, or
+     * <tt>null</tt> if there was no mapping for <tt>key</tt>.
+     */
+    @Nullable
+    public T remove(@NotNull K key) {
+        T temp;
+        synchronized (lock) {
+            temp = data.remove(key);
+        }
+        save();
+        return temp;
+    }
+
+    /**
+     * Removes the mapping for the specified key from this storage if present.
+     *
+     * @param value value whose mapping is to be removed from this storage
+     * @return the previous value associated with <tt>key</tt>, or
+     * <tt>null</tt> if there was no mapping for <tt>key</tt>.
+     */
+    @Nullable
+    public T remove(@NotNull T value) {
+        if (value == null) {
+            return null;
+        }
+        T temp;
+        synchronized (lock) {
+            temp = data.remove(value.getKey());
+        }
+        save();
+        return temp;
+    }
+
+    /**
+     * Adds the specified value in this storage. If the map previously contained
+     * a mapping for the key, the old value is replaced.
+     *
+     * @param value value to be added
+     * @return the previous value associated with <tt>value.getKey()</tt>, or
+     * <tt>null</tt> if there was no mapping for <tt>value.getKey()</tt>.
+     */
+    @Nullable
+    public T add(@NotNull T value) {
+        if (value == null) {
+            return null;
+        }
+        T temp;
+        synchronized (lock) {
+            temp = data.put(value.getKey(), value);
+        }
+        save();
+        return temp;
+    }
+
+    /**
+     * Load data from the associated file
+     */
+    public void load() {
+        if (!getFile().exists()) {
+            return;
+        }
+        try {
+            YamlConfiguration f = new YamlConfiguration();
+            f.options().pathSeparator('\0');
+            f.load(file);
+
+            synchronized (lock) {
+                data.clear();
+                f.getValues(false).entrySet().stream()
+                        .filter(d -> d.getValue() instanceof ConfigurationSection)
+                        .map(Map.Entry::getValue)
+                        .map(v -> getFromSection.apply((ConfigurationSection) v))
+                        .forEach(v -> data.put(v.getKey(), v));
+            }
+        } catch (IOException | InvalidConfigurationException ex) {
+            plugin.getLogger().log(Level.SEVERE, "Failed to load data from " + file.getName(), ex);
+        }
+    }
+
+    /**
+     * Optionally save this storage's data to file if there have been changes made
+     */
+    public void saveChanges() {
+        if (saveTask != null || data.values().stream().anyMatch(v -> v.hasChanged())) {
+            flushSave();
+        }
+    }
+
+    /**
+     * Save this file data. This saves later asynchronously.
+     */
+    public void save() {
+        // save async even if no plugin or if plugin disabled
+        if (saveTask == null) {
+            autosaveTimer = new Timer((plugin != null ? plugin.getName() + "-DataStoreSave-" : "DataStoreSave-") + getFile().getName());
+            autosaveTimer.schedule(saveTask = new SaveTask(), autosaveInterval * 1000L);
+        }
+    }
+
+    /**
+     * Force a new save of this storage's data
+     */
+    public void flushSave() {
+        if (saveTask != null) {
+            //Close Threads
+            saveTask.cancel();
+            autosaveTimer.cancel();
+            saveTask = null;
+            autosaveTimer = null;
+        }
+        YamlConfiguration f = new YamlConfiguration();
+        synchronized (lock) {
+            data.values().stream().forEach(e -> e.saveToSection(f.createSection(e.getConfigKey())));
+        }
+        try {
+            f.save(getFile());
+            data.values().stream().forEach(e -> e.setChanged(false));
+        } catch (IOException ex) {
+            plugin.getLogger().log(Level.SEVERE, "Failed to save data to " + file.getName(), ex);
+        }
+    }
+
+    class SaveTask extends TimerTask {
+
+        @Override
+        public void run() {
+            flushSave();
+        }
+    }
+}