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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package javafx.css;

import javafx.scene.text.Font;

/**
 * A representation of a parsed CSS value. {@code V} is the type of the parsed
 * value, {@code T} is the {@code StyleableProperty} type of the converted value.
 * Instances of {@code ParsedValue} are created by the CSS parser. For example,
 * the parser creates a {@code ParsedValue<String,Color>} when it parses a 
 * web Color. 
 * <p>
 * A ParsedValue is meaningful to the code that calculates actual values from
 * parsed CSS values. Elsewhere the value returned by 
 * {@link #getValue()} is likely to be obscure, abstruse and perplexing. 
 * @since JavaFX 8.0
 */
public class ParsedValue<V, T> {

    /**
     * The CSS property value as created by the parser.
     */
    final protected V value;
    
    /**
     * @return The CSS property value as created by the parser, which may be null
     * or otherwise incomprehensible.
     */
    public final V getValue() { return value; }

    /**
     * The {@code StyleConverter} which converts the parsed value to 
     * the type of the {@link StyleableProperty}. This may be null, in which
     * case {@link #convert(javafx.scene.text.Font) convert}
     * will return {@link #getValue() getValue()}
     */
    final protected StyleConverter<V, T> converter;
    
    /**
     * A {@code StyleConverter} converts the parsed value to 
     * the type of the {@link StyleableProperty}. If the {@code StyleConverter}
     * is null, {@link #convert(javafx.scene.text.Font)}
     * will return {@link #getValue()}
     * @return The {@code StyleConverter} which converts the parsed value to 
     * the type of the {@link StyleableProperty}. May return null.
     */
    public final StyleConverter<V, T> getConverter() { return converter; }

    /**
     * Convenience method for calling 
     * {@link StyleConverter#convert(javafx.css.ParsedValue, javafx.scene.text.Font) convert}
     * on this {@code ParsedValue}.
     * @param font         The {@link Font} to use when converting a
     * <a href="http://www.w3.org/TR/css3-values/#relative-lengths">relative</a>
     * value.
     * @return The value converted to the type of the {@link StyleableProperty}
     * @see #getConverter() 
     */
    @SuppressWarnings("unchecked")
    public T convert(Font font) {
        // unchecked!
        return (T)((converter != null) ? converter.convert(this, font) : value);
    }
    
    /**
     * Create an instance of ParsedValue where the value type V is converted to
     * the target type T using the given converter.
     * If {@code converter} is null, then it is assumed that the type of value 
     * {@code V} and the type of target {@code T} are the same and
     * do not need converted.
     */
    protected ParsedValue(V value, StyleConverter<V, T> converter) {
        this.value = value;
        this.converter = converter;
    }

}
