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Units of Measurement Implementation for Java SE - JDK Integration of Unit-API / JSR 363
/*
* 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 java.math.BigDecimal;
import java.math.MathContext;
import java.util.Objects;
import tec.uom.lib.common.function.ValueSupplier;
import tec.uom.se.AbstractConverter;
/**
*
* This class represents a exponential converter of limited precision. Such converter is used to create inverse of logarithmic unit.
*
*
* This class is package private, instances are created using the {@link LogConverter#inverse()} method.
*
*
* @author Jean-Marie Dautelle
* @author Werner Keil
* @version 1.0, Oct 10, 2016
* @since 1.0
*/
public final class ExpConverter extends AbstractConverter implements ValueSupplier {
/**
*
*/
private static final long serialVersionUID = -8851436813812059827L;
/**
* Holds the logarithmic base.
*/
private final double base;
/**
* Holds the natural logarithm of the base.
*/
private final double logOfBase;
/**
* Creates a logarithmic converter having the specified base.
*
* @param base
* the logarithmic base (e.g. Math.E
for the Natural Logarithm).
*/
public ExpConverter(double base) {
this.base = base;
this.logOfBase = Math.log(base);
}
/**
* Returns the exponential base of this converter.
*
* @return the exponential base (e.g. Math.E
for the Natural Exponential).
*/
public double getBase() {
return base;
}
@Override
public AbstractConverter inverse() {
return new LogConverter(base);
}
@Override
public final String toString() {
if (base == Math.E) {
return "e";
} else {
return "Exp(" + base + ")";
}
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof ExpConverter) {
ExpConverter that = (ExpConverter) obj;
return Objects.equals(base, that.base);
}
return false;
}
@Override
public int hashCode() {
return Objects.hash(base);
}
@Override
public double convert(double amount) {
return Math.exp(logOfBase * amount);
}
@Override
public BigDecimal convert(BigDecimal value, MathContext ctx) throws ArithmeticException {
return BigDecimal.valueOf(convert(value.doubleValue())); // Reverts to
// double
// conversion.
}
@Override
public boolean isLinear() {
return false;
}
@Override
public String getValue() {
return toString();
}
}