/*

   Copyright 2002  The Apache Software Foundation 

   Licensed 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.batik.css.engine.sac;

import org.w3c.css.sac.DescendantSelector;
import org.w3c.css.sac.Selector;
import org.w3c.css.sac.SimpleSelector;

/**
 * This class provides an abstract implementation of the {@link
 * org.w3c.css.sac.DescendantSelector} interface.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id$
 */
public abstract class AbstractDescendantSelector
    implements DescendantSelector,
	       ExtendedSelector {

    /**
     * The ancestor selector.
     */
    protected Selector ancestorSelector;

    /**
     * The simple selector.
     */
    protected SimpleSelector simpleSelector;

    /**
     * Creates a new DescendantSelector object.
     */
    protected AbstractDescendantSelector(Selector ancestor,
                                         SimpleSelector simple) {
	ancestorSelector = ancestor;
	simpleSelector = simple;
    }

    /**
     * Indicates whether some other object is "equal to" this one.
     * @param obj the reference object with which to compare.
     */
    public boolean equals(Object obj) {
        if (obj == null || (obj.getClass() != getClass())) {
            return false;
        }
        AbstractDescendantSelector s = (AbstractDescendantSelector)obj;
        return s.simpleSelector.equals(simpleSelector);
    }

    /**
     * Returns the specificity of this selector.
     */
    public int getSpecificity() {
	return ((ExtendedSelector)ancestorSelector).getSpecificity() +
       	       ((ExtendedSelector)simpleSelector).getSpecificity();
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.DescendantSelector#getAncestorSelector()}.
     */    
    public Selector getAncestorSelector() {
	return ancestorSelector;
    }

    /**
     * <b>SAC</b>: Implements {@link
     * org.w3c.css.sac.DescendantSelector#getSimpleSelector()}.
     */    
    public SimpleSelector getSimpleSelector() {
	return simpleSelector;
    }
}
