src/com/android/tv/dvr/provider/DvrDbFuture.java

/*
 * Copyright (C) 2015 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.tv.dvr.provider;

import android.content.Context;
import android.database.Cursor;
import android.support.annotation.Nullable;
import android.util.Log;
import com.android.tv.common.concurrent.NamedThreadFactory;
import com.android.tv.dvr.data.ScheduledRecording;
import com.android.tv.dvr.data.SeriesRecording;
import com.android.tv.dvr.provider.DvrContract.Schedules;
import com.android.tv.dvr.provider.DvrContract.SeriesRecordings;
import com.android.tv.util.MainThreadExecutor;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executors;

/** {@link DvrDbFuture} that defaults to executing on its own single threaded Executor Service. */
public abstract class DvrDbFuture<ParamsT, ResultT> {
    private static final NamedThreadFactory THREAD_FACTORY =
        new NamedThreadFactory(DvrDbFuture.class.getSimpleName());
    private static final ListeningExecutorService DB_EXECUTOR =
        MoreExecutors.listeningDecorator(Executors.newSingleThreadExecutor(THREAD_FACTORY));

    private static DvrDatabaseHelper sDbHelper;
    private ListenableFuture<ResultT> mFuture;

    final Context mContext;

    private DvrDbFuture(Context context) {
        mContext = context;
    }

    /** Execute the task on the {@link #DB_EXECUTOR} thread and return Future*/
    @SafeVarargs
    public final ListenableFuture<ResultT> executeOnDbThread(
        FutureCallback<ResultT> callback, ParamsT... params) {
            if (sDbHelper == null) {
                sDbHelper = new DvrDatabaseHelper(mContext.getApplicationContext());
            }
            mFuture = DB_EXECUTOR.submit(() -> dbHelperInBackground(params));
            Futures.addCallback(mFuture, callback, MainThreadExecutor.getInstance());
            return mFuture;
    }

    /** Executes in the background after initializing DbHelper} */
    @Nullable
    protected abstract ResultT dbHelperInBackground(ParamsT... params);

    public final boolean isCancelled() {
        return mFuture.isCancelled();
    }

    /** Inserts schedules. */
    public static class AddScheduleFuture
            extends DvrDbFuture<ScheduledRecording, Void> {
        public AddScheduleFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(ScheduledRecording... params) {
            sDbHelper.insertSchedules(params);
            return null;
        }
    }

    /** Update schedules. */
    public static class UpdateScheduleFuture
            extends DvrDbFuture<ScheduledRecording, Void> {
        public UpdateScheduleFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(ScheduledRecording... params) {
            sDbHelper.updateSchedules(params);
            return null;
        }
    }

    /** Delete schedules. */
    public static class DeleteScheduleFuture
            extends DvrDbFuture<ScheduledRecording, Void> {
        public DeleteScheduleFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(ScheduledRecording... params) {
            sDbHelper.deleteSchedules(params);
            return null;
        }
    }

    /** Returns all {@link ScheduledRecording}s. */
    public static class DvrQueryScheduleFuture
            extends DvrDbFuture<Void, List<ScheduledRecording>> {
        public DvrQueryScheduleFuture(Context context) {
            super(context);
        }

        @Override
        @Nullable
        protected final List<ScheduledRecording> dbHelperInBackground(Void... params) {
            if (isCancelled()) {
                return null;
            }
            List<ScheduledRecording> scheduledRecordings = new ArrayList<>();
            try (Cursor c = sDbHelper.query(Schedules.TABLE_NAME, ScheduledRecording.PROJECTION)) {
                while (c.moveToNext() && !isCancelled()) {
                    scheduledRecordings.add(ScheduledRecording.fromCursor(c));
                }
            }
            return scheduledRecordings;
        }
    }

    /** Inserts series recordings. */
    public static class AddSeriesRecordingFuture
            extends DvrDbFuture<SeriesRecording, Void> {
        public AddSeriesRecordingFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(SeriesRecording... params) {
            sDbHelper.insertSeriesRecordings(params);
            return null;
        }
    }

    /** Update series recordings. */
    public static class UpdateSeriesRecordingFuture
            extends DvrDbFuture<SeriesRecording, Void> {
        public UpdateSeriesRecordingFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(SeriesRecording... params) {
            sDbHelper.updateSeriesRecordings(params);
            return null;
        }
    }

    /** Delete series recordings. */
    public static class DeleteSeriesRecordingFuture
            extends DvrDbFuture<SeriesRecording, Void> {
        public DeleteSeriesRecordingFuture(Context context) {
            super(context);
        }

        @Override
        protected final Void dbHelperInBackground(SeriesRecording... params) {
            sDbHelper.deleteSeriesRecordings(params);
            return null;
        }
    }

    /** Returns all {@link SeriesRecording}s. */
    public static class DvrQuerySeriesRecordingFuture
            extends DvrDbFuture<Void, List<SeriesRecording>> {
        private static final String TAG = "DvrQuerySeriesRecording";

        public DvrQuerySeriesRecordingFuture(Context context) {
            super(context);
        }

        @Override
        @Nullable
        protected final List<SeriesRecording> dbHelperInBackground(Void... params) {
            if (isCancelled()) {
                return null;
            }
            List<SeriesRecording> scheduledRecordings = new ArrayList<>();
            try (Cursor c =
                    sDbHelper.query(SeriesRecordings.TABLE_NAME, SeriesRecording.PROJECTION)) {
                while (c.moveToNext() && !isCancelled()) {
                    scheduledRecordings.add(SeriesRecording.fromCursor(c));
                }
            } catch (Exception e) {
                Log.w(TAG, "Can't query dvr series recording data", e);
            }
            return scheduledRecordings;
        }
    }
}