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/*
ConnectBot: simple, powerful, open-source SSH client for Android
Copyright (C) 2007-2008 Kenny Root, Jeffrey Sharkey
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.connectbot.util;
import java.util.LinkedList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
/**
* @author Kenny Root
*
*/
public abstract class RobustSQLiteOpenHelper extends SQLiteOpenHelper {
private static List<String> mTableNames = new LinkedList<String>();
private static List<String> mIndexNames = new LinkedList<String>();
public RobustSQLiteOpenHelper(Context context, String name,
CursorFactory factory, int version) {
super(context, name, factory, version);
}
protected static void addTableName(String tableName) {
mTableNames.add(tableName);
}
protected static void addIndexName(String indexName) {
mIndexNames.add(indexName);
}
@Override
public void onCreate(SQLiteDatabase db) {
dropAllTables(db);
}
@Override
public final void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
try {
onRobustUpgrade(db, oldVersion, newVersion);
} catch (SQLiteException e) {
// The database has entered an unknown state. Try to recover.
try {
regenerateTables(db);
} catch (SQLiteException e2) {
dropAndCreateTables(db);
}
}
}
public abstract void onRobustUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) throws SQLiteException;
private void regenerateTables(SQLiteDatabase db) {
dropAllTablesWithPrefix(db, "OLD_");
for (String tableName : mTableNames)
db.execSQL("ALTER TABLE " + tableName + " RENAME TO OLD_"
+ tableName);
onCreate(db);
for (String tableName : mTableNames)
repopulateTable(db, tableName);
dropAllTablesWithPrefix(db, "OLD_");
}
private void repopulateTable(SQLiteDatabase db, String tableName) {
String columns = getTableColumnNames(db, tableName);
StringBuilder sb = new StringBuilder();
sb.append("INSERT INTO ")
.append(tableName)
.append(" (")
.append(columns)
.append(") SELECT ")
.append(columns)
.append(" FROM OLD_")
.append(tableName);
String sql = sb.toString();
db.execSQL(sql);
}
private String getTableColumnNames(SQLiteDatabase db, String tableName) {
StringBuilder sb = new StringBuilder();
Cursor fields = db.rawQuery("PRAGMA table_info(" + tableName + ")", null);
while (fields.moveToNext()) {
if (!fields.isFirst())
sb.append(", ");
sb.append(fields.getString(1));
}
fields.close();
return sb.toString();
}
private void dropAndCreateTables(SQLiteDatabase db) {
dropAllTables(db);
onCreate(db);
}
private void dropAllTablesWithPrefix(SQLiteDatabase db, String prefix) {
for (String indexName : mIndexNames)
db.execSQL("DROP INDEX IF EXISTS " + prefix + indexName);
for (String tableName : mTableNames)
db.execSQL("DROP TABLE IF EXISTS " + prefix + tableName);
}
private void dropAllTables(SQLiteDatabase db) {
dropAllTablesWithPrefix(db, "");
}
}
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