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 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
 * 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 com.sun.javafx.css.PseudoClassState;

/**
 * PseudoClass represents one unique pseudo-class state. Introducing a 
 * pseudo-class into a JavaFX class only requires that the method
 * {@link javafx.scene.Node#pseudoClassStateChanged(javafx.css.PseudoClass, boolean)}
 * be called when the pseudo-class state changes. Typically, the
 * {@code pseudoClassStateChanged} method is called from the
 * {@code protected void invalidated()} method of one of the property base 
 * classes in the {@code javafx.beans.property} package.
 * <p>
 * Note that if a node has a default pseudo-class state, a horizontal orientation
 * for example, {@code pseudoClassStateChanged} should be called from the 
 * constructor to set the initial state. 
 * <p>
 * The following example would allow &quot;xyzzy&quot; to be used as a
 *  pseudo-class in a CSS selector.
 * <code>
 * <pre>
 *  public boolean isMagic() {
 *       return magic.get();
 *   }
 *
 *   public BooleanProperty magicProperty() {
 *       return magic;
 *   }
 *
 *   public BooleanProperty magic =
 *       new BooleanPropertyBase(false) {
 *
 *       {@literal @}Override protected void invalidated() {
 *           pseudoClassStateChanged(MAGIC_PSEUDO_CLASS. get());
 *       }
 *
 *       {@literal @}Override public Object getBean() {
 *           return MyControl.this;
 *       }
 *
 *       {@literal @}Override public String getName() {
 *           return "magic";
 *       }
 *   }
 *
 *   private static final PseudoClass
 *       MAGIC_PSEUDO_CLASS = PseudoClass.getPseudoClass("xyzzy");
 * </pre>
 * </code>
 * @since JavaFX 8.0
 */
public abstract class PseudoClass {

    /**
     * There is only one PseudoClass instance for a given pseudoClass.
     * @return The PseudoClass for the given pseudoClass. Will not return null.
     * @throws IllegalArgumentException if pseudoClass parameter is null or an empty String
     */
    public static PseudoClass getPseudoClass(String pseudoClass) {
        
        final PseudoClass instance = PseudoClassState.getPseudoClass(pseudoClass);
        return instance;
    }

    /** @return the pseudo-class state */
    abstract public String getPseudoClassName();

}
