get old value when updating DataEntry

Author: HSGamer

agent/core/src/main/java/me/hsgamer/topper/agent/core/DataEntryAgent.java

@@ -7,7 +7,7 @@ default void onCreate(DataEntry<K, V> entry) {
         // EMPTY
     }
 
-    default void onUpdate(DataEntry<K, V> entry) {
+    default void onUpdate(DataEntry<K, V> entry, V oldValue) {
         // EMPTY
     }
 

agent/holder/src/main/java/me/hsgamer/topper/agent/holder/AgentDataHolder.java

@@ -39,8 +39,8 @@ protected final void onCreate(DataEntry<K, V> entry) {
     }
 
     @Override
-    protected final void onUpdate(DataEntry<K, V> entry) {
-        entryAgentList.forEach(agent -> agent.onUpdate(entry));
+    protected void onUpdate(DataEntry<K, V> entry, V oldValue) {
+        entryAgentList.forEach(agent -> agent.onUpdate(entry, oldValue));
     }
 
     @Override

agent/storage/src/main/java/me/hsgamer/topper/agent/storage/StorageAgent.java

@@ -102,7 +102,7 @@ public void beforeStop() {
     }
 
     @Override
-    public void onUpdate(DataEntry<K, V> entry) {
+    public void onUpdate(DataEntry<K, V> entry, V oldValue) {
         queue.add(new AbstractMap.SimpleImmutableEntry<>(entry.getKey(), entry.getValue()));
     }
 

core/src/main/java/me/hsgamer/topper/core/DataEntry.java

@@ -32,8 +32,9 @@ public void setValue(UnaryOperator<V> operator) {
 
     public void setValue(V value, boolean notify) {
         if (Objects.equals(this.value, value)) return;
+        V oldValue = this.value;
         this.value = value;
-        if (notify) holder.onUpdate(this);
+        if (notify) holder.onUpdate(this, oldValue);
     }
 
     public void setValue(UnaryOperator<V> operator, boolean notify) {

core/src/main/java/me/hsgamer/topper/core/DataHolder.java

@@ -23,7 +23,7 @@ protected void onCreate(DataEntry<K, V> entry) {
     protected void onRemove(DataEntry<K, V> entry) {
     }
 
-    protected void onUpdate(DataEntry<K, V> entry) {
+    protected void onUpdate(DataEntry<K, V> entry, V oldValue) {
     }
 
     public final String getName() {

spigot/plugin/src/main/java/me/hsgamer/topper/spigot/plugin/event/GenericEntryUpdateEvent.java

@@ -13,18 +13,20 @@ public class GenericEntryUpdateEvent extends Event {
     private final String group;
     private final String holder;
     private final UUID uuid;
+    private final @Nullable Double oldValue;
     private final @Nullable Double value;
 
-    public GenericEntryUpdateEvent(String group, String holder, UUID uuid, @Nullable Double value, boolean async) {
+    public GenericEntryUpdateEvent(String group, String holder, UUID uuid, @Nullable Double oldValue, @Nullable Double value, boolean async) {
         super(async);
         this.group = group;
         this.holder = holder;
         this.uuid = uuid;
+        this.oldValue = oldValue;
         this.value = value;
     }
 
-    public GenericEntryUpdateEvent(String holder, UUID uuid, @Nullable Double value, boolean async) {
-        this(DEFAULT_GROUP, holder, uuid, value, async);
+    public GenericEntryUpdateEvent(String holder, UUID uuid, @Nullable Double oldValue, @Nullable Double value, boolean async) {
+        this(DEFAULT_GROUP, holder, uuid, oldValue, value, async);
     }
 
     public static HandlerList getHandlerList() {
@@ -43,6 +45,10 @@ public UUID getUuid() {
         return uuid;
     }
 
+    public @Nullable Double getOldValue() {
+        return oldValue;
+    }
+
     public @Nullable Double getValue() {
         return value;
     }

spigot/plugin/src/main/java/me/hsgamer/topper/spigot/plugin/holder/NumberTopHolder.java

@@ -71,8 +71,8 @@ public void start() {
         });
         addEntryAgent(new DataEntryAgent<UUID, Double>() {
             @Override
-            public void onUpdate(DataEntry<UUID, Double> entry) {
-                Bukkit.getPluginManager().callEvent(new GenericEntryUpdateEvent(name, entry.getKey(), entry.getValue(), true));
+            public void onUpdate(DataEntry<UUID, Double> entry, Double oldValue) {
+                Bukkit.getPluginManager().callEvent(new GenericEntryUpdateEvent(name, entry.getKey(), oldValue, entry.getValue(), true));
             }
         });
     }