DBHelper.java

package com.jbirdvegas.mgerrit.database;

/*
 * Copyright (C) 2013 Android Open Kang Project (AOKP)
 *  Author: Evan Conway (P4R4N01D), 2013
 *
 *  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.
 */

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

class DBHelper extends SQLiteOpenHelper {
    static final String TAG = "DbHelper";

    // Don't forget to set this when a change to the database is made!
    // This must be strictly ascending, but can skip numbers
    private static final int DB_VERSION = 17;
    private static List<DatabaseTable> mTables;
    private Context mContext;

    /**
     * Constructor should be private to prevent direct instantiation.
     * make call to static factory method "getInstance()" instead.
     */
    protected DBHelper(Context context, String dbName) {
        super(context, dbName, null, DB_VERSION);
        mContext = context;
        registerTables();
    }

    // Called only once, first time the DB is created. Create all the tables here
    @Override
    public void onCreate(SQLiteDatabase db) {
        for (Class<? extends DatabaseTable> table : DatabaseTable.tables) {
            try {
                Method getTableInst = table.getDeclaredMethod("getInstance");
                DatabaseTable tableInst = (DatabaseTable) getTableInst.invoke(null);

                Method createTable = table.getDeclaredMethod("create", String.class, SQLiteDatabase.class);
                createTable.invoke(tableInst, TAG, db);
            } catch (Exception e) {
                throw new RuntimeException("Unable to create table for " + table.getSimpleName(), e);
            }
        }
    }

    // Called whenever newVersion > oldVersion. Can do some version number checking
    //  in here to avoid completely emptying the database, although it may be a good
    //  idea to re-create the lot again.
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        for (Class<? extends DatabaseTable> table : DatabaseTable.tables) {
            try {
                String tableName = table.getField("TABLE").get(null).toString();
                db.execSQL("drop table if exists " + tableName);
            } catch (IllegalAccessException e) {
                throw new IllegalAccessError(DatabaseTable.PRIVATE_TABLE_CONST);
            } catch (NoSuchFieldException e) {
                throw new NoSuchFieldError(DatabaseTable.NO_TABLE_CONST);
            }
        }

        Log.d(TAG, "Database Updated.");
        onCreate(db); // run onCreate to get new database
    }

    // Sanitise the names of the Gerrit instances so we do not create odd file names
    public static String getDatabaseName(String gerritURL) {
        String[] parts = gerritURL.split("\\.");
        String name;
        if (parts.length < 2)  name = parts[parts.length - 1];
        else name = parts[parts.length - 2];

        // Conservative naming scheme - allow only letters. digits and underscores.
        return name.toLowerCase().replaceAll("[^a-z0-9_]+", "") + ".db";
    }

    private static void instantiateTables() {
        mTables = new ArrayList<>();
        for (Class<? extends DatabaseTable> table : DatabaseTable.tables) {
            try {
                Method getTableInst = table.getDeclaredMethod("getInstance");
                DatabaseTable tableInst = (DatabaseTable) getTableInst.invoke(null);
                mTables.add(tableInst);
            } catch (Exception e) {
                throw new RuntimeException("Unable to instantiate table " + table.getSimpleName(), e);
            }
        }
    }

    private void registerTables() {
        instantiateTables();
        for (DatabaseTable table : mTables) {
            table.registerContentObserver(mContext);
        }
    }

    protected void shutdown() {
        this.close();
        for (DatabaseTable table : mTables) {
            table.unRegisterContentObserver(mContext);
        }
    }
}