HSQLDB example source code file (SetFunction.java)
The HSQLDB SetFunction.java source code/* Copyright (c) 2001-2008, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package org.hsqldb;
import java.lang.Math;
import java.math.BigDecimal;
import java.math.BigInteger;
import org.hsqldb.lib.HashSet;
import org.hsqldb.store.ValuePool;
/**
* Implementation of SQL set functions (currently only aggregate functions).
* This reduces temporary Object creation by SUM and AVG functions for
* INTEGER and narrower types.
*
* @author fredt@users
* @author boucherb@users
* @version 1.7.3
* @since 1.7.2
*
*/
public class SetFunction {
private HashSet distinctValues;
private boolean isDistinct;
//
private int setType;
private int type;
//
private int count;
//
private boolean hasNull;
private boolean every = true;
private boolean some = false;
private long currentLong;
private double currentDouble;
private BigDecimal currentBigDecimal;
private Object currentValue;
SetFunction(int setType, int type, boolean isDistinct) {
this.setType = setType;
this.type = type;
if (isDistinct) {
this.isDistinct = true;
distinctValues = new HashSet();
}
if (setType == Expression.VAR_SAMP
|| setType == Expression.STDDEV_SAMP) {
this.sample = true;
}
}
void add(Session session, Object item) throws HsqlException {
if (item == null) {
hasNull = true;
return;
}
if (isDistinct && !distinctValues.add(item)) {
return;
}
count++;
switch (setType) {
case Expression.COUNT :
return;
case Expression.AVG :
case Expression.SUM : {
switch (type) {
case Types.TINYINT :
case Types.SMALLINT :
case Types.INTEGER :
currentLong += ((Number) item).intValue();
return;
case Types.BIGINT :
addLong(((Number) item).longValue());
return;
case Types.REAL :
case Types.FLOAT :
case Types.DOUBLE :
currentDouble += ((Number) item).doubleValue();
return;
case Types.NUMERIC :
case Types.DECIMAL :
if (currentBigDecimal == null) {
currentBigDecimal = (BigDecimal) item;
} else {
currentBigDecimal =
currentBigDecimal.add((BigDecimal) item);
}
return;
default :
throw Trace.error(Trace.SUM_OF_NON_NUMERIC);
}
}
case Expression.MIN : {
if (currentValue == null) {
currentValue = item;
return;
}
if (Column.compare(
session.database.collation, currentValue, item,
type) > 0) {
currentValue = item;
}
return;
}
case Expression.MAX : {
if (currentValue == null) {
currentValue = item;
return;
}
if (Column.compare(
session.database.collation, currentValue, item,
type) < 0) {
currentValue = item;
}
return;
}
case Expression.EVERY :
if (!(item instanceof Boolean)) {
throw Trace.error(Trace.WRONG_DATA_TYPE);
}
every &= ((Boolean) item).booleanValue();
return;
case Expression.SOME :
if (!(item instanceof Boolean)) {
throw Trace.error(Trace.WRONG_DATA_TYPE);
}
some |= ((Boolean) item).booleanValue();
return;
case Expression.STDDEV_POP :
case Expression.STDDEV_SAMP :
case Expression.VAR_POP :
case Expression.VAR_SAMP :
if (!(item instanceof Number)) {
throw Trace.error(Trace.WRONG_DATA_TYPE);
}
addDataPoint((Number) item);
return;
}
}
Object getValue() throws HsqlException {
if (setType == Expression.COUNT) {
return ValuePool.getInt(count);
}
if (count == 0) {
return null;
}
switch (setType) {
case Expression.AVG : {
switch (type) {
case Types.TINYINT :
case Types.SMALLINT :
case Types.INTEGER :
return new Long(currentLong / count);
case Types.BIGINT : {
long value = getLongSum().divide(
BigInteger.valueOf(count)).longValue();
return new Long(value);
}
case Types.REAL :
case Types.FLOAT :
case Types.DOUBLE :
return new Double(currentDouble / count);
case Types.NUMERIC :
case Types.DECIMAL :
return currentBigDecimal.divide(new BigDecimal(count),
BigDecimal.ROUND_DOWN);
default :
throw Trace.error(Trace.SUM_OF_NON_NUMERIC);
}
}
case Expression.SUM : {
switch (type) {
case Types.TINYINT :
case Types.SMALLINT :
case Types.INTEGER :
return new Long(currentLong);
case Types.BIGINT :
return new BigDecimal(getLongSum());
case Types.REAL :
case Types.FLOAT :
case Types.DOUBLE :
return new Double(currentDouble);
case Types.NUMERIC :
case Types.DECIMAL :
return currentBigDecimal;
default :
throw Trace.error(Trace.SUM_OF_NON_NUMERIC);
}
}
case Expression.MIN :
case Expression.MAX :
return currentValue;
case Expression.EVERY :
return every ? Boolean.TRUE
: Boolean.FALSE;
case Expression.SOME :
return some ? Boolean.TRUE
: Boolean.FALSE;
case Expression.STDDEV_POP :
case Expression.STDDEV_SAMP :
return getStdDev();
case Expression.VAR_POP :
case Expression.VAR_SAMP :
return getVariance();
default :
throw Trace.error(Trace.INVALID_CONVERSION);
}
}
/**
* During parsing and before an instance of SetFunction is created,
* getType is called with type parameter set to correct type when main
* SELECT statements contain aggregates. It is called with Types.NULL
* when SELECT statements within INSERT or UPDATE contian aggregates.
*
*/
static int getType(int setType, int type) throws HsqlException {
switch (setType) {
case Expression.COUNT :
return Types.INTEGER;
case Expression.AVG : {
switch (type) {
case Types.TINYINT :
case Types.SMALLINT :
case Types.INTEGER :
case Types.BIGINT :
return Types.BIGINT;
case Types.REAL :
case Types.FLOAT :
case Types.DOUBLE :
return Types.DOUBLE;
case Types.NUMERIC :
case Types.DECIMAL :
return Types.DECIMAL;
default :
return Types.NULL;
}
}
case Expression.SUM : {
switch (type) {
case Types.TINYINT :
case Types.SMALLINT :
case Types.INTEGER :
return Types.BIGINT;
case Types.BIGINT :
return Types.DECIMAL;
case Types.REAL :
case Types.FLOAT :
case Types.DOUBLE :
return Types.DOUBLE;
case Types.NUMERIC :
case Types.DECIMAL :
return Types.DECIMAL;
default :
return Types.NULL;
}
}
case Expression.MIN :
case Expression.MAX :
return type;
case Expression.EVERY :
case Expression.SOME :
return Types.BOOLEAN;
case Expression.STDDEV_POP :
case Expression.STDDEV_SAMP :
case Expression.VAR_POP :
case Expression.VAR_SAMP :
return Types.DOUBLE;
default :
throw Trace.error(Trace.INVALID_CONVERSION);
}
}
// long sum - originally a separate class
/**
* Maintain the sum of multiple long values without creating a new
* BigInteger object for each addition.
*/
static BigInteger multiplier = BigInteger.valueOf(0x0000000100000000L);
// BigInteger bigint = BigInteger.ZERO;
long hi;
long lo;
void addLong(long value) {
if (value == 0) {}
else if (value > 0) {
hi += value >> 32;
lo += value & 0x00000000ffffffffL;
} else {
if (value == Long.MIN_VALUE) {
hi -= 0x000000080000000L;
} else {
long temp = ~value + 1;
hi -= temp >> 32;
lo -= temp & 0x00000000ffffffffL;
}
}
// bigint = bigint.add(BigInteger.valueOf(value));
}
BigInteger getLongSum() throws HsqlException {
BigInteger biglo = BigInteger.valueOf(lo);
BigInteger bighi = BigInteger.valueOf(hi);
BigInteger result = (bighi.multiply(multiplier)).add(biglo);
/*
if ( result.compareTo(bigint) != 0 ){
throw Trace.error(Trace.GENERAL_ERROR, "longSum mismatch");
}
*/
return result;
}
// end long sum
// statistics support - written by Campbell
// this section was orginally an independent class
private double sk;
private double vk;
private long n;
private boolean initialized;
private boolean sample;
private void addDataPoint(Number x) { // optimized
double xi;
double xsi;
long nm1;
if (x == null) {
return;
}
xi = x.doubleValue();
if (!initialized) {
n = 1;
sk = xi;
vk = 0.0;
initialized = true;
return;
}
n++;
nm1 = (n - 1);
xsi = (sk - (xi * nm1));
vk += ((xsi * xsi) / n) / nm1;
sk += xi;
}
private Number getVariance() {
if (!initialized) {
return null;
}
return sample ? (n == 1) ? null // NULL (not NaN) is correct in this case
: new Double(vk / (double) (n - 1))
: new Double(vk / (double) (n));
}
private Number getStdDev() {
if (!initialized) {
return null;
}
return sample ? (n == 1) ? null // NULL (not NaN) is correct in this case
: new Double(Math.sqrt(vk / (double) (n - 1)))
: new Double(Math.sqrt(vk / (double) (n)));
}
// end statistics support
}
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