UnitsConverter.java
/* Copyright 2002-2022 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.orekit.utils.units;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
/** Converter between units.
* <p>
* Instances of this class are immutable.
* </p>
* @author Luc Maisonobe
* @since 11.0
*/
public class UnitsConverter {
/** Identity converter. */
public static final UnitsConverter IDENTITY =
new UnitsConverter(Unit.ONE, Unit.ONE);
/** Percents to units converter. */
public static final UnitsConverter PERCENTS_TO_UNIT =
new UnitsConverter(Unit.PERCENT, Unit.ONE);
/** Arcseconds to radians converter. */
public static final UnitsConverter ARC_SECONDS_TO_RADIANS =
new UnitsConverter(Unit.parse("as"), Unit.RADIAN);
/** Milli arcseconds to radians converter. */
public static final UnitsConverter MILLI_ARC_SECONDS_TO_RADIANS =
new UnitsConverter(Unit.parse("mas"), Unit.RADIAN);
/** Milli seconds to seconds converter. */
public static final UnitsConverter MILLI_SECONDS_TO_SECONDS =
new UnitsConverter(Unit.parse("ms"), Unit.SECOND);
/** Days to seconds converter. */
public static final UnitsConverter DAYS_TO_SECONDS =
new UnitsConverter(Unit.DAY, Unit.SECOND);
/** Kilometres to metres converter. */
public static final UnitsConverter KILOMETRES_TO_METRES =
new UnitsConverter(Unit.KILOMETRE, Unit.METRE);
/** Square kilometres to square metres converter. */
public static final UnitsConverter KILOMETRES_2_TO_METRES_2 =
new UnitsConverter(Unit.parse("km²"), Unit.parse("m²"));
/** km³/s² to m³/s² converter. */
public static final UnitsConverter KM3_P_S2_TO_M3_P_S2 =
new UnitsConverter(Unit.parse("km³/s²"), Unit.parse("m³/s²"));
/** Source unit. */
private final Unit from;
/** Destination unit. */
private final Unit to;
/** Conversion factor. */
private final double factor;
/** Simple constructor.
* @param from source unit
* @param to destination unit
*/
public UnitsConverter(final Unit from, final Unit to) {
this.from = from;
this.to = to;
if (!from.sameDimension(to)) {
throw new OrekitException(OrekitMessages.INCOMPATIBLE_UNITS,
from.getName(), to.getName());
}
this.factor = from.getScale() / to.getScale();
}
/** Get the source unit.
* @return source unit
*/
public Unit getFrom() {
return from;
}
/** Get the destination unit.
* @return destination unit
*/
public Unit getTo() {
return to;
}
/** Convert a value.
* @param value value in the {@link #getFrom() source unit}
* @return value converted in the {@link #getTo() destination unit}
*/
public double convert(final double value) {
return factor * value;
}
/** {@inheritDoc} */
@Override
public String toString() {
return from.getName() + " → " + to.getName();
}
}