WindUpFactory.java

/* Copyright 2002-2025 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,
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package org.orekit.estimation.measurements.gnss;

import java.util.HashMap;
import java.util.Map;

import org.orekit.gnss.SatelliteSystem;

/** Factory for {@link WindUp wind-up} modifiers.
 * <p>
 * The factory ensures the same instance is returned for all
 * satellite/receiver pair, thus preserving phase continuity
 * for successive measurements involving the same pair.
 * </p>
 * @author Luc Maisonobe
 * @since 10.1
 */
public class WindUpFactory {

    /** Modifiers cache. */
    private final Map<SatelliteSystem, Map<Integer, Map<String, WindUp>>> modifiers;

    /** Simple constructor.
     */
    public WindUpFactory() {
        this.modifiers = new HashMap<>();
    }

    /** Get a modifier for a satellite/receiver pair.
     * @param system system the satellite belongs to
     * @param prnNumber PRN number
     * @param emitterDipole emitter dipole
     * @param receiverName name of the receiver
     * @return modifier for the satellite/receiver pair
     */
    public WindUp getWindUp(final SatelliteSystem system, final int prnNumber,
                            final Dipole emitterDipole, final String receiverName) {
        // select satellite system
        final Map<Integer, Map<String, WindUp>> systemModifiers;
        synchronized (modifiers) {
            systemModifiers = modifiers.computeIfAbsent(system, s -> new HashMap<>());

            // select satellite
            final Map<String, WindUp> satelliteModifiers =
                systemModifiers.computeIfAbsent(prnNumber, n -> new HashMap<>());

            // select receiver
            return satelliteModifiers.computeIfAbsent(receiverName, r -> new WindUp(emitterDipole));

        }

    }

}