com.ibm.icu.number.Scale Maven / Gradle / Ivy
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// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
package com.ibm.icu.number;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;
import com.ibm.icu.impl.number.DecimalQuantity;
import com.ibm.icu.impl.number.RoundingUtils;
/**
* A class that defines a quantity by which a number should be multiplied when formatting.
*
*
* To create a Multiplier, use one of the factory methods.
*
* @stable ICU 62
* @see NumberFormatter
*/
public class Scale {
private static final Scale DEFAULT = new Scale(0, null);
private static final Scale HUNDRED = new Scale(2, null);
private static final Scale THOUSAND = new Scale(3, null);
private static final BigDecimal BIG_DECIMAL_100 = BigDecimal.valueOf(100);
private static final BigDecimal BIG_DECIMAL_1000 = BigDecimal.valueOf(1000);
final int magnitude;
final BigDecimal arbitrary;
final BigDecimal reciprocal;
final MathContext mc;
private Scale(int magnitude, BigDecimal arbitrary) {
this(magnitude, arbitrary, RoundingUtils.DEFAULT_MATH_CONTEXT_34_DIGITS);
}
private Scale(int magnitude, BigDecimal arbitrary, MathContext mc) {
if (arbitrary != null) {
// Attempt to convert the BigDecimal to a magnitude multiplier.
// ICU-20000: JDKs have inconsistent behavior on stripTrailingZeros() for Zero.
arbitrary =
arbitrary.compareTo(BigDecimal.ZERO) == 0
? BigDecimal.ZERO
: arbitrary.stripTrailingZeros();
if (arbitrary.precision() == 1 && arbitrary.unscaledValue().equals(BigInteger.ONE)) {
// Success!
magnitude -= arbitrary.scale();
arbitrary = null;
}
}
this.magnitude = magnitude;
this.arbitrary = arbitrary;
this.mc = mc;
// We need to use a math context in order to prevent non-terminating decimal expansions.
// This is only used when dividing by the multiplier.
if (arbitrary != null && BigDecimal.ZERO.compareTo(arbitrary) != 0) {
this.reciprocal = BigDecimal.ONE.divide(arbitrary, mc);
} else {
this.reciprocal = null;
}
}
/**
* Do not change the value of numbers when formatting or parsing.
*
* @return A Multiplier to prevent any multiplication.
* @stable ICU 62
* @see NumberFormatter
*/
public static Scale none() {
return DEFAULT;
}
/**
* Multiply numbers by 100 before formatting. Useful for combining with a percent unit:
*
*
* NumberFormatter.with().unit(NoUnit.PERCENT).multiplier(Multiplier.powerOfTen(2))
*
*
* @return A Multiplier for passing to the setter in NumberFormatter.
* @stable ICU 62
* @see NumberFormatter
*/
public static Scale powerOfTen(int power) {
if (power == 0) {
return DEFAULT;
} else if (power == 2) {
return HUNDRED;
} else if (power == 3) {
return THOUSAND;
} else {
return new Scale(power, null);
}
}
/**
* Multiply numbers by an arbitrary value before formatting. Useful for unit conversions.
*
* This method takes a BigDecimal; also see the version that takes a double.
*
* @return A Multiplier for passing to the setter in NumberFormatter.
* @stable ICU 62
* @see NumberFormatter
*/
public static Scale byBigDecimal(BigDecimal multiplicand) {
if (multiplicand.compareTo(BigDecimal.ONE) == 0) {
return DEFAULT;
} else if (multiplicand.compareTo(BIG_DECIMAL_100) == 0) {
return HUNDRED;
} else if (multiplicand.compareTo(BIG_DECIMAL_1000) == 0) {
return THOUSAND;
} else {
return new Scale(0, multiplicand);
}
}
/**
* Multiply numbers by an arbitrary value before formatting. Useful for unit conversions.
*
* This method takes a double; also see the version that takes a BigDecimal.
*
* @return A Multiplier for passing to the setter in NumberFormatter.
* @stable ICU 62
* @see NumberFormatter
*/
public static Scale byDouble(double multiplicand) {
if (multiplicand == 1) {
return DEFAULT;
} else if (multiplicand == 100.0) {
return HUNDRED;
} else if (multiplicand == 1000.0) {
return THOUSAND;
} else {
return new Scale(0, BigDecimal.valueOf(multiplicand));
}
}
/**
* Multiply a number by both a power of ten and by an arbitrary double value before formatting.
*
* @return A Multiplier for passing to the setter in NumberFormatter.
* @stable ICU 62
* @see NumberFormatter
*/
public static Scale byDoubleAndPowerOfTen(double multiplicand, int power) {
return new Scale(power, BigDecimal.valueOf(multiplicand));
}
/**
* Returns whether the multiplier will change the number.
*/
boolean isValid() {
return magnitude != 0 || arbitrary != null;
}
/**
* @internal
* @deprecated ICU 62 This API is ICU internal only.
*/
@Deprecated
public Scale withMathContext(MathContext mc) {
// TODO: Make this public?
if (this.mc.equals(mc)) {
return this;
}
return new Scale(magnitude, arbitrary, mc);
}
/**
* @internal
* @deprecated ICU 62 This API is ICU internal only.
*/
@Deprecated
public void applyTo(DecimalQuantity quantity) {
quantity.adjustMagnitude(magnitude);
if (arbitrary != null) {
quantity.multiplyBy(arbitrary);
}
}
/**
* @internal
* @deprecated ICU 62 This API is ICU internal only.
*/
@Deprecated
public void applyReciprocalTo(DecimalQuantity quantity) {
quantity.adjustMagnitude(-magnitude);
if (reciprocal != null) {
quantity.multiplyBy(reciprocal);
quantity.roundToMagnitude(quantity.getMagnitude() - mc.getPrecision(), mc);
}
}
}