nz.co.gregs.dbvolution.internal.sqlite.MissingStandardFunctions Maven / Gradle / Ivy
/*
* Copyright 2015 gregorygraham.
*
* 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 nz.co.gregs.dbvolution.internal.sqlite;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import nz.co.gregs.dbvolution.databases.SQLiteDB;
import org.sqlite.Function;
/**
*
* Support DBvolution at
* Patreon
*
* @author gregorygraham
*/
public class MissingStandardFunctions {
/**
*
* @param db
* @param connection
* @throws SQLException
*/
public static void addFunctions(SQLiteDB db, Connection connection) throws SQLException {
Function.create(connection, "TRUNC", new Trunc());
Function.create(connection, "LOCATION_OF", new LocationOf());
Function.create(connection, "CURRENT_USER", new CurrentUser(db.getUsername()));
Function.create(connection, "STDEV", new StandardDeviation());
Function.create(connection, "REGEXP_REPLACE", new RegexpReplace());
}
private static class RegexpReplace extends Function {
@Override
protected void xFunc() throws SQLException {
String original = value_text(0);
String regexp = value_text(1);
String replace = value_text(2);
result(original.replaceAll(regexp, replace));
}
}
private static class Trunc extends Function {
@Override
protected void xFunc() throws SQLException {
Double original = value_double(0);
result(original.longValue());
}
}
private static class LocationOf extends Function {
@Override
protected void xFunc() throws SQLException {
String original = value_text(0);
String find = value_text(1);
result(original.indexOf(find) + 1);
}
}
private static class CurrentUser extends Function {
private final String currentUser;
public CurrentUser(String currentUser) {
this.currentUser = currentUser;
}
@Override
protected void xFunc() throws SQLException {
result(currentUser);
}
}
// Function.create(conn, "mySum", new Function.Aggregate() {
private static class StandardDeviation extends Function.Aggregate {
private final List longs = new ArrayList();
/**
* Performed for each row during the aggregation process
*
* 1 Database exceptions may be thrown
*/
@Override
protected void xStep() throws SQLException {
Long longValue = value_long(0);
longs.add(longValue);
}
/**
* Produces the final result from the aggregation process.
*
* 1 Database exceptions may be thrown
*/
@Override
protected void xFinal() throws SQLException {
double sum = 0.0;
for (Long long1 : longs) {
sum += long1;
}
Double mean = sum / longs.size();
List squaredDistances = new ArrayList();
for (Long long1 : longs) {
final double dist = mean - long1;
squaredDistances.add(dist * dist);
}
for (Double dist : squaredDistances) {
sum += dist;
}
double variance = sum / squaredDistances.size();
result(Math.sqrt(variance));
}
@Override
public Object clone() throws CloneNotSupportedException {
return super.clone(); //To change body of generated methods, choose Tools | Templates.
}
}
private MissingStandardFunctions() {
}
}