diff --git a/src/main/java/org/holoeasy/line/BlockLine.kt b/src/main/java/org/holoeasy/line/BlockLine.kt
index 21b38ba..f64ac52 100644
--- a/src/main/java/org/holoeasy/line/BlockLine.kt
+++ b/src/main/java/org/holoeasy/line/BlockLine.kt
@@ -8,12 +8,16 @@ import org.bukkit.inventory.ItemStack
 import org.bukkit.plugin.Plugin
 import org.holoeasy.ext.send
 import org.holoeasy.packet.IPacket
+import org.holoeasy.reactive.MutableState
+
+class BlockLine(plugin: Plugin, obj: ItemStack) : ILine<ItemStack> {
 
-class BlockLine(plugin: Plugin, override var obj: ItemStack) : ILine<ItemStack> {
 
     private val line: Line = Line(plugin, EntityType.DROPPED_ITEM)
     private val resetVelocity = IPacket.get(IPacket.Type.VELOCITY).velocity(line.entityID, 0, 0,0)
 
+    private val _mutableStateOf = MutableState(obj)
+
     override val plugin: Plugin
         get() = line.plugin
 
@@ -26,6 +30,12 @@ class BlockLine(plugin: Plugin, override var obj: ItemStack) : ILine<ItemStack>
     override val location: Location?
         get() = line.location
 
+    override var obj : ItemStack
+        get() = _mutableStateOf.get()
+        set(value) = _mutableStateOf.set(value)
+
+    override lateinit var pvt: ILine.PrivateConfig
+
     override fun setLocation(value: Location) {
         line.location = value
     }
diff --git a/src/main/java/org/holoeasy/line/ClickableTextLine.kt b/src/main/java/org/holoeasy/line/ClickableTextLine.kt
index d3a7563..a10b020 100644
--- a/src/main/java/org/holoeasy/line/ClickableTextLine.kt
+++ b/src/main/java/org/holoeasy/line/ClickableTextLine.kt
@@ -69,6 +69,8 @@ class ClickableTextLine(private val line: TextLine, minHitDistance: Float, maxHi
             line.obj = value
         }
 
+    override var pvt: ILine.PrivateConfig = line.pvt
+
     override fun setLocation(value: Location) {
         line.setLocation(value)
         this.updateHitBox()
diff --git a/src/main/java/org/holoeasy/line/ILine.kt b/src/main/java/org/holoeasy/line/ILine.kt
index 7aeacd7..2ad7d08 100644
--- a/src/main/java/org/holoeasy/line/ILine.kt
+++ b/src/main/java/org/holoeasy/line/ILine.kt
@@ -3,10 +3,22 @@ package org.holoeasy.line
 import org.bukkit.Location
 import org.bukkit.entity.Player
 import org.bukkit.plugin.Plugin
+import org.holoeasy.hologram.Hologram
+import org.holoeasy.reactive.Observer
 import org.jetbrains.annotations.ApiStatus
 
 interface ILine<T> {
 
+    data class PrivateConfig(private val line: ILine<*>) : Observer {
+
+        var hologram : Hologram? = null
+        override fun observerUpdate() {
+            hologram?.let {
+                line.update(it.seeingPlayers)
+            }
+        }
+    }
+
     val plugin: Plugin
 
     val type: Type
@@ -17,6 +29,8 @@ interface ILine<T> {
 
     var obj: T
 
+    var pvt : PrivateConfig
+
     fun setLocation(value: Location)
 
     fun hide(player: Player)
diff --git a/src/main/java/org/holoeasy/line/TextLine.kt b/src/main/java/org/holoeasy/line/TextLine.kt
index d9a08fa..adad372 100644
--- a/src/main/java/org/holoeasy/line/TextLine.kt
+++ b/src/main/java/org/holoeasy/line/TextLine.kt
@@ -15,6 +15,7 @@ class TextLine(plugin: Plugin, obj: String, override val args: Array<PlayerFun>?
 
     private val line: Line = Line(plugin, EntityType.ARMOR_STAND)
 
+
     override var obj: String = ""
 
     var clickEvent : ClickEvent? = null
@@ -60,6 +61,9 @@ class TextLine(plugin: Plugin, obj: String, override val args: Array<PlayerFun>?
     override val location: Location?
         get() = line.location
 
+
+    override lateinit var pvt: ILine.PrivateConfig
+
     override fun setLocation(value: Location) {
         line.location = value
         if (clickable) {
diff --git a/src/main/java/org/holoeasy/reactive/MutableState.kt b/src/main/java/org/holoeasy/reactive/MutableState.kt
new file mode 100644
index 0000000..8816d72
--- /dev/null
+++ b/src/main/java/org/holoeasy/reactive/MutableState.kt
@@ -0,0 +1,29 @@
+package org.holoeasy.reactive
+
+data class MutableState<T>(private var value : T) {
+
+    private val observers= mutableListOf<Observer>()
+
+    fun get() : T {
+        return value
+    }
+
+    fun set(newValue : T) {
+        value = newValue
+        this.notifyObservers()
+    }
+
+    fun addObserver(observer: Observer) {
+        observers.add(observer)
+    }
+
+    fun removeObserver(observer: Observer) {
+        observers.remove(observer)
+    }
+
+    private fun notifyObservers() {
+        for (observer in observers) {
+            observer.observerUpdate()
+        }
+    }
+}
diff --git a/src/main/java/org/holoeasy/reactive/Observer.kt b/src/main/java/org/holoeasy/reactive/Observer.kt
new file mode 100644
index 0000000..162dfbb
--- /dev/null
+++ b/src/main/java/org/holoeasy/reactive/Observer.kt
@@ -0,0 +1,5 @@
+package org.holoeasy.reactive
+
+interface Observer {
+    fun observerUpdate()
+}
\ No newline at end of file