Implement ConnectionStatusManager class including a implementation of a FSM to...

Implement ConnectionStatusManager class including a implementation of a FSM to handle connection states

app/src/main/java/chat/rocket/android/ConnectionStatusManager.kt

+package chat.rocket.android
+
+import chat.rocket.android.service.KeepAliveJob
+import unquietcode.tools.esm.EnumStateMachine
+import unquietcode.tools.esm.TransitionException
+
+object ConnectionStatusManager {
+    enum class State {
+        OFFLINE, CONNECTING, ONLINE
+    }
+
+    private const val DEBUG = false
+    private val stateMachine: EnumStateMachine<State>
+
+    init {
+        stateMachine = EnumStateMachine(State.OFFLINE)
+
+        stateMachine.addTransitions(State.OFFLINE, State.CONNECTING)
+        stateMachine.addTransitions(State.CONNECTING, State.ONLINE, State.OFFLINE)
+        stateMachine.addTransitions(State.ONLINE, State.OFFLINE)
+    }
+
+    @Synchronized
+    fun currentState() = stateMachine.currentState()
+
+    @Synchronized
+    fun setOnline(callback: TransitionCallback) {
+        KeepAliveJob.cancelPendingJobRequests()
+        tryTransitionTo(State.ONLINE, callback)
+    }
+
+    @Synchronized
+    fun setConnecting(callback: TransitionCallback) {
+        KeepAliveJob.cancelPendingJobRequests()
+        tryTransitionTo(State.CONNECTING, callback)
+    }
+
+    @Synchronized
+    fun setConnectionError(callback: TransitionCallback) {
+        KeepAliveJob.schedule()
+        tryTransitionTo(State.OFFLINE, callback)
+    }
+
+    private fun tryTransitionTo(newState: State, callback: TransitionCallback) {
+        try {
+            stateMachine.transition(newState)
+            callback.onTransitioned(true)
+        } catch (e: TransitionException) {
+            if (DEBUG) {
+                e.printStackTrace()
+            }
+            callback.onTransitioned(false)
+        }
+    }
+
+    interface TransitionCallback {
+        fun onTransitioned(success: Boolean)
+    }
+}
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