core/sis-utility/src/main/java/org/apache/sis/internal/converter/AngleConverter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.sis.internal.converter;

import java.util.Set;
import org.apache.sis.measure.Angle;
import org.apache.sis.util.ObjectConverter;
import org.apache.sis.math.FunctionProperty;


/**
 * Handles conversions between {@link Angle} and {@link Double}.
 *
 * <div class="section">Immutability and thread safety</div>
 * This class is immutable and thus inherently thread-safe.
 * The same {@link #INSTANCE} can be passed between threads without synchronization.
 *
 * @author  Martin Desruisseaux (Geomatys)
 * @version 0.3
 * @since   0.3
 * @module
 */
public final class AngleConverter extends SystemConverter<Angle,Double> {
    /**
     * For cross-version compatibility.
     */
    private static final long serialVersionUID = -5124032874967170238L;

    /**
     * The unique instance.
     */
    static final AngleConverter INSTANCE = new AngleConverter();

    /**
     * Creates a new converter.
     */
    public AngleConverter() {                           // Instantiated by ServiceLoader.
        super(Angle.class, Double.class);
    }

    /**
     * Returns the unique instance.
     *
     * @return unique instance.
     */
    @Override
    public ObjectConverter<Angle,Double> unique() {
        return INSTANCE;
    }

    /**
     * Returns the inverse converter.
     *
     * @return {@link Inverse}.
     */
    @Override
    public ObjectConverter<Double,Angle> inverse() {
        return Inverse.INSTANCE;
    }

    /**
     * Declares that the converter is bijective.
     *
     * @return injective and surjective function properties (among others).
     */
    @Override
    public Set<FunctionProperty> properties() {
        return bijective();
    }

    /**
     * Converts the given angle.
     *
     * @param   object  the angle to convert.
     * @return  angular value in degrees.
     */
    @Override
    public Double apply(final Angle object) {
        return object.degrees();
    }


    /**
     * The inverse of {@link AngleConverter}.
     *
     * <div class="section">Thread safety</div>
     * This class is immutable, and thus inherently thread-safe.
     */
    public static final class Inverse extends SystemConverter<Double,Angle> {
        /**
         * For cross-version compatibility.
         */
        private static final long serialVersionUID = -1736966474591258159L;

        /**
         * The unique instance.
         */
        static final Inverse INSTANCE = new Inverse();

        /**
         * Creates a new converter.
         */
        public Inverse() {                              // Instantiated by ServiceLoader.
            super(Double.class, Angle.class);
        }

        /**
         * Returns the unique instance.
         *
         * @return the unique instance.
         */
        @Override
        public ObjectConverter<Double,Angle> unique() {
            return INSTANCE;
        }

        /**
         * Returns the inverse converter.
         *
         * @return {@link AngleConverter}.
         */
        @Override
        public ObjectConverter<Angle,Double> inverse() {
            return AngleConverter.INSTANCE;
        }

        /**
         * Declares that the converter is bijective.
         *
         * @return injective and surjective function properties (among others).
         */
        @Override
        public Set<FunctionProperty> properties() {
            return bijective();
        }

        /**
         * Converts the given angle.
         *
         * @param  object  angular value in degrees.
         * @return the angle object for the given value.
         */
        @Override
        public Angle apply(final Double object) {
            return new Angle(object);
        }
    }
}