GreenDao 万能升级

package com.xuan.parent;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.text.TextUtils;
import android.util.Log;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import de.greenrobot.dao.AbstractDao;
import de.greenrobot.dao.internal.DaoConfig;

public class MigrationHelper {

private static final String CONVERSION_CLASS_NOT_FOUND_EXCEPTION = "MIGRATION HELPER - CLASS DOESN'T MATCH WITH THE CURRENT PARAMETERS";
private static MigrationHelper instance;

public static MigrationHelper getInstance() {
if(instance == null) {
instance = new MigrationHelper();
}
return instance;
}

public void migrate(SQLiteDatabase db, Class<? extends AbstractDao<?, ?>>... daoClasses) {
generateTempTables(db, daoClasses);
DaoMaster.dropAllTables(db, true);
DaoMaster.createAllTables(db, false);
restoreData(db, daoClasses);
}

private void generateTempTables(SQLiteDatabase db, Class<? extends AbstractDao<?, ?>>... daoClasses) {
for(int i = 0; i < daoClasses.length; i++) {
DaoConfig daoConfig = new DaoConfig(db, daoClasses[i]);

String divider = "";
String tableName = daoConfig.tablename;
String tempTableName = daoConfig.tablename.concat("_TEMP");
ArrayList<String> properties = new ArrayList<>();

StringBuilder createTableStringBuilder = new StringBuilder();

createTableStringBuilder.append("CREATE TABLE ").append(tempTableName).append(" (");

for(int j = 0; j < daoConfig.properties.length; j++) {
String columnName = daoConfig.properties[j].columnName;

if(getColumns(db, tableName).contains(columnName)) {
properties.add(columnName);

String type = null;

try {
type = getTypeByClass(daoConfig.properties[j].type);
} catch (Exception exception) {
//Crashlytics.logException(exception);
}

createTableStringBuilder.append(divider).append(columnName).append(" ").append(type);

if(daoConfig.properties[j].primaryKey) {
createTableStringBuilder.append(" PRIMARY KEY");
}

divider = ",";
}
}
createTableStringBuilder.append(");");

db.execSQL(createTableStringBuilder.toString());

StringBuilder insertTableStringBuilder = new StringBuilder();

insertTableStringBuilder.append("INSERT INTO ").append(tempTableName).append(" (");
insertTableStringBuilder.append(TextUtils.join(",", properties));
insertTableStringBuilder.append(") SELECT ");
insertTableStringBuilder.append(TextUtils.join(",", properties));
insertTableStringBuilder.append(" FROM ").append(tableName).append(";");

db.execSQL(insertTableStringBuilder.toString());
}
}

private void restoreData(SQLiteDatabase db, Class<? extends AbstractDao<?, ?>>... daoClasses) {
for(int i = 0; i < daoClasses.length; i++) {
DaoConfig daoConfig = new DaoConfig(db, daoClasses[i]);

String tableName = daoConfig.tablename;
String tempTableName = daoConfig.tablename.concat("_TEMP");
ArrayList<String> properties = new ArrayList();

for (int j = 0; j < daoConfig.properties.length; j++) {
String columnName = daoConfig.properties[j].columnName;

if(getColumns(db, tempTableName).contains(columnName)) {
properties.add(columnName);
}
}

StringBuilder insertTableStringBuilder = new StringBuilder();

insertTableStringBuilder.append("INSERT INTO ").append(tableName).append(" (");
insertTableStringBuilder.append(TextUtils.join(",", properties));
insertTableStringBuilder.append(") SELECT ");
insertTableStringBuilder.append(TextUtils.join(",", properties));
insertTableStringBuilder.append(" FROM ").append(tempTableName).append(";");

StringBuilder dropTableStringBuilder = new StringBuilder();

dropTableStringBuilder.append("DROP TABLE ").append(tempTableName);

db.execSQL(insertTableStringBuilder.toString());
db.execSQL(dropTableStringBuilder.toString());
}
}

private String getTypeByClass(Class<?> type) throws Exception {
if(type.equals(String.class)) {
return "TEXT";
}
if(type.equals(Long.class) || type.equals(Integer.class) || type.equals(long.class)) {
return "INTEGER";
}
if(type.equals(Boolean.class)) {
return "BOOLEAN";
}

Exception exception = new Exception(CONVERSION_CLASS_NOT_FOUND_EXCEPTION.concat(" - Class: ").concat(type.toString()));
// Crashlytics.logException(exception);
throw exception;
}

private static List<String> getColumns(SQLiteDatabase db, String tableName) {
List<String> columns = new ArrayList<>();
Cursor cursor = null;
try {
cursor = db.rawQuery("SELECT * FROM " + tableName + " limit 1", null);
if (cursor != null) {
columns = new ArrayList<>(Arrays.asList(cursor.getColumnNames()));
}
} catch (Exception e) {
Log.v(tableName, e.getMessage(), e);
e.printStackTrace();
} finally {
if (cursor != null)
cursor.close();
}
return columns;
}
}

public static class DevOpenHelper extends OpenHelper {
public DevOpenHelper(Context context, String name, CursorFactory factory) {
super(context, name, factory);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables");
/* dropAllTables(db, true);
onCreate(db);*/
MigrationHelper.getInstance().migrate(db,
ChildDao.class,
ParentDao.class);

}
}