ru.ming13.gambit.database.DatabaseOperator.java Source code

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Here is the source code for ru.ming13.gambit.database.DatabaseOperator.java

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/*
 * Copyright 2012 Artur Dryomov
 *
 * 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 ru.ming13.gambit.database;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.support.annotation.NonNull;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import ru.ming13.gambit.util.SqlBuilder;

public class DatabaseOperator {
    private static final String DATABASE_ALIAS = "db";
    private static final String DATABASE_PREFIX = "database";

    private final Context context;

    public static DatabaseOperator of(@NonNull Context context) {
        return new DatabaseOperator(context);
    }

    private DatabaseOperator(Context context) {
        this.context = context.getApplicationContext();
    }

    public void writeDatabaseContents(@NonNull OutputStream databaseContentsStream) {
        try {
            FileUtils.copyFile(getDatabaseFile(), databaseContentsStream);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private File getDatabaseFile() {
        return context.getDatabasePath(DatabaseSchema.DATABASE_NAME).getAbsoluteFile();
    }

    public void readDatabaseContents(@NonNull InputStream databaseContentsStream) {
        File sourceDatabaseFile = getDatabaseFile(databaseContentsStream);

        SQLiteDatabase sourceDatabase = new DatabaseOpenHelper(context, sourceDatabaseFile.getAbsolutePath())
                .getReadableDatabase();
        SQLiteDatabase destinationDatabase = new DatabaseOpenHelper(context).getWritableDatabase();

        deleteDatabaseContents(destinationDatabase);
        insertDatabaseContents(destinationDatabase, sourceDatabaseFile);

        sourceDatabase.close();
        destinationDatabase.close();

        sourceDatabaseFile.delete();
    }

    private File getDatabaseFile(InputStream databaseContentsStream) {
        try {
            File databaseFile = File.createTempFile(DATABASE_PREFIX, null, context.getCacheDir());

            FileUtils.copyInputStreamToFile(databaseContentsStream, databaseFile);

            return databaseFile;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private void deleteDatabaseContents(SQLiteDatabase database) {
        try {
            database.beginTransaction();

            database.execSQL(SqlBuilder.buildDeletionClause(DatabaseSchema.Tables.CARDS));
            database.execSQL(SqlBuilder.buildDeletionClause(DatabaseSchema.Tables.DECKS));

            database.setTransactionSuccessful();
        } finally {
            database.endTransaction();
        }
    }

    private void insertDatabaseContents(SQLiteDatabase database, File databaseFile) {
        database.execSQL(SqlBuilder.buildAttachingClause(databaseFile.getAbsolutePath(), DATABASE_ALIAS));

        try {
            database.beginTransaction();

            database.execSQL(SqlBuilder.buildInsertionClause(DatabaseSchema.Tables.DECKS, DATABASE_ALIAS));
            database.execSQL(SqlBuilder.buildInsertionClause(DatabaseSchema.Tables.CARDS, DATABASE_ALIAS));

            database.setTransactionSuccessful();
        } finally {
            database.endTransaction();
        }

        database.execSQL(SqlBuilder.buildDetachingClause(DATABASE_ALIAS));
    }
}