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/*
* ConnectBot: simple, powerful, open-source SSH client for Android
* Copyright 2007 Kenny Root, Jeffrey Sharkey
*
* 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 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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