/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 * 
 *    (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
 *    
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library 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
 *    Lesser General Public License for more details.
 */
package org.geotools.styling;

import javax.measure.quantity.Length;
import javax.measure.unit.NonSI;
import javax.measure.unit.SI;
import javax.measure.unit.Unit;

/**
 * Defines the Units of Measure (UOMs) specified by the OGC SE standard and their mappings to Java
 * Units defined in <code>javax.measure.unit</code>. Each entry in this enum provides both the Java
 * Unit for the given UOM and the corresponding String that is defined by the SE standard.
 *
 * @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/main/src/main/java/org/geotools/styling/UomOgcMapping.java $
 */
public enum UomOgcMapping {

    METRE(SI.METER, "http://www.opengeospatial.org/se/units/metre"), FOOT(NonSI.FOOT,
            "http://www.opengeospatial.org/se/units/foot"), PIXEL(NonSI.PIXEL,
            "http://www.opengeospatial.org/se/units/pixel");

    private String seString;

    private Unit<Length> unit;

    /**
     * Internal constructor: specifies the UOM mapping passing a specific Java Unit and the
     * corresponding OGC SE string.
     * 
     * @param unit
     *            a Java Unit (e.g., <code>SI.METER</code>).
     * @param seString
     *            a String that follows the OGC SE specification.
     */
    private UomOgcMapping(Unit<Length> unit, String seString) {
        this.unit = unit;
        this.seString = seString;
    }

    @Override
    public String toString() {
        return seString;
    }

    /**
     * Returns the String defined by the OGC SE specification for the unit of measure.
     * 
     * @return a String that follows the OGC SE specification
     */
    public String getSEString() {
        return seString;
    }

    /**
     * Returns the Java Unit that corresponds to the unit of measure.
     * 
     * @return a Java Unit (e.g., <code>SI.METER</code>).
     */
    public Unit<Length> getUnit() {
        return unit;
    }

    /**
     * Returns the appropriate UOM mapping for a given OGC SE standard string.
     * 
     * @param seString
     *            a String that follows the OGC SE specification.
     * @return the corresponding UnitOfMeasure.
     * @throws IllegalArgumentException
     *             if the provided String is not a valid OGC SE value.
     */
    public static UomOgcMapping get(String seString) throws IllegalArgumentException {
        for (UomOgcMapping uom : UomOgcMapping.values()) {
            if (uom.getSEString().equals(seString))
                return uom;
        }
        throw new IllegalArgumentException("'" + seString
                + "' is not a valid OGC SE standard Unit of Measure");
    }

    /**
     * Returns the appropriate UOM mapping for a given Java Unit.
     * 
     * @param unit
     *            a Java Unit (e.g., <code>SI.METER</code>).
     * @return the corresponding UnitOfMeasure.
     * @throws IllegalArgumentException
     *             if the provided Unit is not part of the OGC SE specification.
     */
    public static UomOgcMapping get(Unit<Length> unit) throws IllegalArgumentException {
        for (UomOgcMapping uom : UomOgcMapping.values()) {
            if (uom.getUnit().equals(unit))
                return uom;
        }
        throw new IllegalArgumentException("'" + unit
                + "' is not a valid OGC SE standard Unit of Measure");
    }
}