[Settings] Code refactor for availability session

Code refactor for session design of availability status config.

Bug: 141833767
Test: manual
Change-Id: Ia4982bc4036abbcff5ee1a4bba69bdf6f70ad657

src/com/android/settings/network/telephony/TelephonyStatusControlSession.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2020 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.android.settings.network.telephony;
+
+import android.util.Log;
+
+import com.android.settings.core.BasePreferenceController;
+import com.android.settingslib.core.AbstractPreferenceController;
+import com.android.settingslib.utils.ThreadUtils;
+
+import java.util.Collection;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+/**
+ * Session for controlling the status of TelephonyPreferenceController(s).
+ *
+ * Within this session, result of {@link BasePreferenceController#availabilityStatus()}
+ * would be under control.
+ */
+public class TelephonyStatusControlSession implements AutoCloseable {
+
+    private static final String LOG_TAG = "TelephonyStatusControlSS";
+
+    private Collection<AbstractPreferenceController> mControllers;
+    private Future<Boolean> mResult;
+
+    /**
+     * Buider of session
+     */
+    public static class Builder {
+        private Collection<AbstractPreferenceController> mControllers;
+
+        /**
+         * Constructor
+         *
+         * @param controllers is a collection of {@link AbstractPreferenceController}
+         *        which would have {@link BasePreferenceController#availabilityStatus()}
+         *        under control within this session.
+         */
+        public Builder(Collection<AbstractPreferenceController> controllers) {
+            mControllers = controllers;
+        }
+
+        /**
+         * Method to build this session.
+         * @return {@link TelephonyStatusControlSession} session been setup.
+         */
+        public TelephonyStatusControlSession build() {
+            return new TelephonyStatusControlSession(mControllers);
+        }
+    }
+
+    private TelephonyStatusControlSession(Collection<AbstractPreferenceController> controllers) {
+        mControllers = controllers;
+        mResult = ThreadUtils.postOnBackgroundThread(() ->
+            setupAvailabilityStatus(controllers)
+        );
+    }
+
+    /**
+     * Close the session.
+     *
+     * No longer control the status.
+     */
+    public void close() {
+        //check the background thread is finished then unset the status of availability.
+        try {
+            mResult.get();
+        } catch (ExecutionException | InterruptedException exception) {
+            Log.e(LOG_TAG, "setup availability status failed!", exception);
+        }
+        unsetAvailabilityStatus(mControllers);
+    }
+
+    private Boolean setupAvailabilityStatus(
+            Collection<AbstractPreferenceController> controllerLists) {
+        try {
+            controllerLists.stream()
+                    .filter(controller -> controller instanceof TelephonyAvailabilityHandler)
+                    .map(TelephonyAvailabilityHandler.class::cast)
+                    .forEach(controller -> {
+                        int status = ((BasePreferenceController) controller)
+                                .getAvailabilityStatus();
+                        controller.setAvailabilityStatus(status);
+                    });
+            return true;
+        } catch (Exception exception) {
+            Log.e(LOG_TAG, "Setup availability status failed!", exception);
+            return false;
+        }
+    }
+
+    private void unsetAvailabilityStatus(
+            Collection<AbstractPreferenceController> controllerLists) {
+        controllerLists.stream()
+                .filter(controller -> controller instanceof TelephonyAvailabilityHandler)
+                .map(TelephonyAvailabilityHandler.class::cast)
+                .forEach(controller -> {
+                    controller.unsetAvailabilityStatus();
+                });
+    }
+}