tec.uom.se.function.RationalConverter Maven / Gradle / Ivy
/*
* Units of Measurement Implementation for Java SE
* Copyright (c) 2005-2018, Jean-Marie Dautelle, Werner Keil, Otavio Santana.
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Neither the name of JSR-363 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 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package tec.uom.se.function;
import javax.measure.UnitConverter;
import tec.uom.lib.common.function.ValueSupplier;
import tec.uom.se.AbstractConverter;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;
import java.util.Objects;
import java.util.function.DoubleSupplier;
import java.util.function.Supplier;
/**
*
* This class represents a converter multiplying numeric values by an exact scaling factor (represented as the quotient of two BigInteger
* numbers).
*
*
* @author Jean-Marie Dautelle
* @author Werner Keil
* @version 1.0, Oct 11, 2016
* @since 1.0
*/
public final class RationalConverter extends AbstractConverter implements ValueSupplier, Supplier, DoubleSupplier {
/**
*
*/
private static final long serialVersionUID = 3563384008357680074L;
/**
* Holds the converter dividend.
*/
private final BigInteger dividend;
/**
* Holds the converter divisor (always positive).
*/
private final BigInteger divisor;
/**
* Creates a rational converter with the specified dividend and divisor.
*
* @param dividend
* the dividend.
* @param divisor
* the positive divisor.
* @throws IllegalArgumentException
* if divisor <= 0
* @throws IllegalArgumentException
* if dividend == divisor
*/
public RationalConverter(BigInteger dividend, BigInteger divisor) {
if (divisor.compareTo(BigInteger.ZERO) <= 0)
throw new IllegalArgumentException("Negative or zero divisor");
if (dividend.equals(divisor))
throw new IllegalArgumentException("Would result in identity converter");
this.dividend = dividend; // Exact conversion.
this.divisor = divisor; // Exact conversion.
}
/**
* Convenience method equivalent to new RationalConverter(BigInteger.valueOf(dividend), BigInteger.valueOf(divisor))
*
* @param dividend
* the dividend.
* @param divisor
* the positive divisor.
* @throws IllegalArgumentException
* if divisor <= 0
* @throws IllegalArgumentException
* if dividend == divisor
*/
public RationalConverter(long dividend, long divisor) {
this(BigInteger.valueOf(dividend), BigInteger.valueOf(divisor));
}
/**
* Convenience method equivalent to new RationalConverter(dividend, divisor)
*
* @param dividend
* the dividend.
* @param divisor
* the positive divisor.
* @throws IllegalArgumentException
* if divisor <= 0
* @throws IllegalArgumentException
* if dividend == divisor
*/
public static RationalConverter of(BigInteger dividend, BigInteger divisor) {
return new RationalConverter(dividend, divisor);
}
/**
* Convenience method equivalent to new RationalConverter(dividend, divisor)
*
* @param dividend
* the dividend.
* @param divisor
* the positive divisor.
* @throws IllegalArgumentException
* if divisor <= 0
* @throws IllegalArgumentException
* if dividend == divisor
*/
public static RationalConverter of(long dividend, long divisor) {
return new RationalConverter(dividend, divisor);
}
/**
* Convenience method equivalent to new RationalConverter(BigDecimal.valueOf(dividend).toBigInteger(),
* BigDecimal.valueOf(divisor).toBigInteger())
*
* @param dividend
* the dividend.
* @param divisor
* the positive divisor.
* @throws IllegalArgumentException
* if divisor <= 0
* @throws IllegalArgumentException
* if dividend == divisor
*/
public static RationalConverter of(double dividend, double divisor) {
return new RationalConverter(BigDecimal.valueOf(dividend).toBigInteger(), BigDecimal.valueOf(divisor).toBigInteger());
}
/**
* Returns the integer dividend for this rational converter.
*
* @return this converter dividend.
*/
public BigInteger getDividend() {
return dividend;
}
/**
* Returns the integer (positive) divisor for this rational converter.
*
* @return this converter divisor.
*/
public BigInteger getDivisor() {
return divisor;
}
@Override
public double convert(double value) {
return value * toDouble(dividend) / toDouble(divisor);
}
// Optimization of BigInteger.doubleValue() (implementation too
// inneficient).
private static double toDouble(BigInteger integer) {
return (integer.bitLength() < 64) ? integer.longValue() : integer.doubleValue();
}
@Override
public BigDecimal convert(BigDecimal value, MathContext ctx) throws ArithmeticException {
BigDecimal decimalDividend = new BigDecimal(dividend, 0);
BigDecimal decimalDivisor = new BigDecimal(divisor, 0);
return value.multiply(decimalDividend, ctx).divide(decimalDivisor, ctx);
}
@Override
public UnitConverter concatenate(UnitConverter converter) {
if (!(converter instanceof RationalConverter))
return super.concatenate(converter);
RationalConverter that = (RationalConverter) converter;
BigInteger newDividend = this.getDividend().multiply(that.getDividend());
BigInteger newDivisor = this.getDivisor().multiply(that.getDivisor());
BigInteger gcd = newDividend.gcd(newDivisor);
newDividend = newDividend.divide(gcd);
newDivisor = newDivisor.divide(gcd);
return (newDividend.equals(BigInteger.ONE) && newDivisor.equals(BigInteger.ONE)) ? IDENTITY : new RationalConverter(newDividend, newDivisor);
}
@Override
public RationalConverter inverse() {
return dividend.signum() == -1 ? new RationalConverter(getDivisor().negate(), getDividend().negate()) : new RationalConverter(getDivisor(),
getDividend());
}
@Override
public final String toString() {
return "RationalConverter(" + dividend + "," + divisor + ")";
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof RationalConverter) {
RationalConverter that = (RationalConverter) obj;
return Objects.equals(dividend, that.dividend) && Objects.equals(divisor, that.divisor);
}
return false;
}
@Override
public int hashCode() {
return Objects.hash(dividend, divisor);
}
@Override
public boolean isLinear() {
return true;
}
@Override
public Double getValue() {
return getAsDouble();
}
@Override
public double getAsDouble() {
return toDouble(dividend) / toDouble(divisor);
}
@Override
public Double get() {
return getValue();
}
}