FixedTransformProvider.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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 * See the License for the specific language governing permissions and
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package org.orekit.frames;

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

import org.hipparchus.CalculusFieldElement;
import org.hipparchus.Field;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.FieldAbsoluteDate;

/**
** Transform provider using fixed transform.
 * @author Luc Maisonobe
 */
public class FixedTransformProvider implements TransformProvider {

    /** Fixed transform. */
    private final Transform transform;

    /** Cached field-based transforms. */
    private final transient Map<Field<? extends CalculusFieldElement<?>>, FieldTransform<? extends CalculusFieldElement<?>>> cached;

    /** Simple constructor.
     * @param transform fixed transform
     */
    public FixedTransformProvider(final Transform transform) {
        this.transform = transform;
        this.cached    = new HashMap<>();
    }

    /** {@inheritDoc} */
    public Transform getTransform(final AbsoluteDate date) {
        return transform;
    }

    /** {@inheritDoc} */
    @SuppressWarnings("unchecked")
    @Override
    public <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date) {
        synchronized (cached) {
            return (FieldTransform<T>) cached.computeIfAbsent(date.getField(),
                                                            f -> new FieldTransform<>((Field<T>) f, transform));
        }
    }

}