Java tutorial
/* * This file is part of Goko. * * Goko is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Goko is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Goko. If not, see <http://www.gnu.org/licenses/>. */ package org.goko.core.common.measure.quantity; import java.math.BigDecimal; import java.math.MathContext; import java.util.List; import org.apache.commons.lang3.StringUtils; import org.goko.core.common.exception.GkException; import org.goko.core.common.exception.GkTechnicalException; import org.goko.core.common.measure.converter.UnitConverter; import org.goko.core.common.measure.units.AbstractUnit; import org.goko.core.common.measure.units.Unit; public abstract class AbstractQuantity<Q extends Quantity<Q>> implements Quantity<Q> { private BigDecimal value; private Unit<Q> unit; protected AbstractQuantity(BigDecimal value, Unit<Q> unit) { super(); this.value = value; this.unit = unit; } protected AbstractQuantity(Q quantity) { super(); this.value = quantity.value(quantity.getUnit()); this.unit = quantity.getUnit(); } protected UnitConverter getConverterTo(Unit<Q> unit) throws GkTechnicalException { if (unit instanceof AbstractUnit<?>) { throw new GkTechnicalException("Incompatible units..."); } return this.getUnit().getConverterToReferenceUnit().then(unit.getConverterToReferenceUnit().inverse()); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#to(org.goko.core.common.measure.units.Unit) */ @Override public Q to(Unit<Q> unit) { if (unit == getUnit()) { return createQuantity(value, unit); } UnitConverter converter = getUnit().getConverterTo(unit); return createQuantity(converter.convert(value), unit); } /** * @return the unit */ public Unit<Q> getUnit() { return unit; } /** * @param unit the unit to set */ public void setUnit(Unit<Q> unit) { this.unit = unit; } public boolean equals(Q obj) { return value.compareTo(obj.value(getUnit())) == 0; } public boolean almostEquals(Q obj, double error) { return value.subtract(obj.value(getUnit())).abs().doubleValue() <= error; } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#value(org.goko.core.common.measure.units.Unit) */ @Override public BigDecimal value(Unit<Q> unit) { if (unit == getUnit()) { return value; } return to(unit).value(unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#doubleValue(org.goko.core.common.measure.units.Unit) */ @Override public double doubleValue(Unit<Q> unit) { return value(unit).doubleValue(); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#add(org.goko.core.common.measure.quantity.Quantity) */ @Override public Q add(Q q) { return createQuantity(value.add(q.value(this.unit)), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#subtract(org.goko.core.common.measure.quantity.Quantity) */ @Override public Q subtract(Q q) { return createQuantity(value.subtract(q.value(this.unit)), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#multiply(java.lang.Number) */ @Override public Q multiply(BigDecimal n) { return createQuantity(value.multiply(n), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#multiply(int) */ @Override public Q multiply(int n) { return createQuantity(value.multiply(new BigDecimal(n)), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#divide(java.lang.Number) */ @Override public Q divide(BigDecimal n) { return createQuantity(value.divide(n, MathContext.DECIMAL64), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#divide(int) */ @Override public Q divide(int n) { return createQuantity(value.divide(new BigDecimal(n), MathContext.DECIMAL64), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#divide(org.goko.core.common.measure.quantity.Quantity) */ @Override public BigDecimal divide(Q q) { return value.divide(q.value(unit), MathContext.DECIMAL64); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#abs() */ @Override public Q abs() { return createQuantity(value.abs(), unit); } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#negate() */ @Override public Q negate() { return createQuantity(value.negate(), unit); } protected abstract Q createQuantity(BigDecimal value, Unit<Q> unit); /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#lowerThan(org.goko.core.common.measure.quantity.Quantity) */ @Override public boolean lowerThan(Q quantity) { return value.compareTo(quantity.value(getUnit())) < 0; } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#lowerThanOrEqualTo(org.goko.core.common.measure.quantity.Quantity) */ @Override public boolean lowerThanOrEqualTo(Q quantity) { return value.compareTo(quantity.value(getUnit())) <= 0; } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#greaterThan(org.goko.core.common.measure.quantity.Quantity) */ @Override public boolean greaterThan(Q quantity) { return value.compareTo(quantity.value(getUnit())) > 0; } /** (inheritDoc) * @see org.goko.core.common.measure.quantity.Quantity#greaterThanOrEqualTo(org.goko.core.common.measure.quantity.Quantity) */ @Override public boolean greaterThanOrEqualTo(Q quantity) { return value.compareTo(quantity.value(getUnit())) >= 0; } protected Q parse(String value, List<Unit<Q>> lstUnit) throws GkException { // Try to extract unit String leftNumericValue = value; Unit<Q> foundUnit = null; for (Unit<Q> existingUnit : lstUnit) { if (StringUtils.contains(value, existingUnit.getSymbol())) { leftNumericValue = StringUtils.remove(value, existingUnit.getSymbol()).trim(); foundUnit = (Unit<Q>) existingUnit; break; } } if (foundUnit == null) { throw new GkTechnicalException("No unit found in quantity [" + leftNumericValue + "]"); } return createQuantity(new BigDecimal(leftNumericValue), foundUnit); } /** (inheritDoc) * @see java.lang.Object#hashCode() */ @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((unit == null) ? 0 : unit.hashCode()); result = prime * result + ((value == null) ? 0 : value.hashCode()); return result; } /** (inheritDoc) * @see java.lang.Object#equals(java.lang.Object) */ @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; AbstractQuantity<Q> other = (AbstractQuantity<Q>) obj; if (unit == null) { if (other.unit != null) return false; } else if (!unit.equals(other.unit)) return false; if (value == null) { if (other.value != null) return false; } else if (!value.equals(other.value)) return false; return true; } /** (inheritDoc) * @see java.lang.Object#toString() */ @Override public String toString() { return QuantityUtils.format((Q) this); } }