1 files changed, 103 insertions, 0 deletions
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdaterState.java b/updater_sample/src/com/example/android/systemupdatersample/UpdaterState.java
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index 000000000..36a90982e
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+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdaterState.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.android.systemupdatersample;
+
+import android.util.SparseArray;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Controls updater state.
+ */
+public class UpdaterState {
+
+    public static final int IDLE = 0;
+    public static final int ERROR = 1;
+    public static final int RUNNING = 2;
+    public static final int PAUSED = 3;
+    public static final int SLOT_SWITCH_REQUIRED = 4;
+    public static final int REBOOT_REQUIRED = 5;
+
+    private static final SparseArray<String> STATE_MAP = new SparseArray<>();
+
+    static {
+        STATE_MAP.put(0, "IDLE");
+        STATE_MAP.put(1, "ERROR");
+        STATE_MAP.put(2, "RUNNING");
+        STATE_MAP.put(3, "PAUSED");
+        STATE_MAP.put(4, "SLOT_SWITCH_REQUIRED");
+        STATE_MAP.put(5, "REBOOT_REQUIRED");
+    }
+
+    /**
+     * Allowed state transitions. It's a map: key is a state, value is a set of states that
+     * are allowed to transition to from key.
+     */
+    private static final ImmutableMap<Integer, ImmutableSet<Integer>> TRANSITIONS =
+            ImmutableMap.of(
+                    IDLE, ImmutableSet.of(RUNNING),
+                    RUNNING, ImmutableSet.of(ERROR, PAUSED, REBOOT_REQUIRED, SLOT_SWITCH_REQUIRED),
+                    PAUSED, ImmutableSet.of(RUNNING),
+                    SLOT_SWITCH_REQUIRED, ImmutableSet.of(ERROR)
+            );
+
+    private AtomicInteger mState;
+
+    public UpdaterState(int state) {
+        this.mState = new AtomicInteger(state);
+    }
+
+    /**
+     * Returns updater state.
+     */
+    public int get() {
+        return mState.get();
+    }
+
+    /**
+     * Sets the updater state.
+     *
+     * @throws InvalidTransitionException if transition is not allowed.
+     */
+    public void set(int newState) throws InvalidTransitionException {
+        int oldState = mState.get();
+        if (!TRANSITIONS.get(oldState).contains(newState)) {
+            throw new InvalidTransitionException(
+                    "Can't transition from " + oldState + " to " + newState);
+        }
+        mState.set(newState);
+    }
+
+    /**
+     * Converts status code to status name.
+     */
+    public static String getStateText(int state) {
+        return STATE_MAP.get(state);
+    }
+
+    /**
+     * Defines invalid state transition exception.
+     */
+    public static class InvalidTransitionException extends Exception {
+        public InvalidTransitionException(String msg) {
+            super(msg);
+        }
+    }
+}