/*
 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/pattern/UnionPattern.java,v 1.8 2006/02/05 21:47:42 elharo Exp $
 * $Revision: 1.8 $
 * $Date: 2006/02/05 21:47:42 $
 *
 * ====================================================================
 *
 * Copyright 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   * Neither the name of the Jaxen Project nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ====================================================================
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Jaxen Project and was originally
 * created by bob mcwhirter <bob@werken.com> and
 * James Strachan <jstrachan@apache.org>.  For more information on the
 * Jaxen Project, please see <http://www.jaxen.org/>.
 *
 * $Id: UnionPattern.java,v 1.8 2006/02/05 21:47:42 elharo Exp $
 */

package org.orbeon.jaxen.pattern;

import org.orbeon.jaxen.Context;
import org.orbeon.jaxen.JaxenException;

/** <p><code>UnionPattern</code> represents a union pattern.</p>
  *
  * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
  * @version $Revision: 1.8 $
  */
public class UnionPattern extends Pattern {

    private Pattern lhs;
    private Pattern rhs;
    private short nodeType = ANY_NODE;
    private String matchesNodeName = null;


    public UnionPattern()
    {
    }

    public UnionPattern(Pattern lhs, Pattern rhs)
    {
        this.lhs = lhs;
        this.rhs = rhs;
        init();
    }


    public Pattern getLHS()
    {
        return lhs;
    }

    public void setLHS(Pattern lhs)
    {
        this.lhs = lhs;
        init();
    }

    public Pattern getRHS()
    {
        return rhs;
    }

    public void setRHS(Pattern rhs)
    {
        this.rhs = rhs;
        init();
    }


    // Pattern interface
    //-------------------------------------------------------------------------

    /** @return true if the pattern matches the given node
      */
    public boolean matches( Object node, Context context ) throws JaxenException
    {
        return lhs.matches( node, context ) || rhs.matches( node, context );
    }

    public Pattern[] getUnionPatterns()
    {
        return new Pattern[] { lhs, rhs };
    }


    public short getMatchType()
    {
        return nodeType;
    }


    public String getMatchesNodeName()
    {
        return matchesNodeName;
    }


    public Pattern simplify()
    {
        this.lhs = lhs.simplify();
        this.rhs = rhs.simplify();
        init();
        return this;
    }

    public String getText()
    {
        return lhs.getText() + " | " + rhs.getText();
    }

    public String toString()
    {
        return super.toString() + "[ lhs: " + lhs + " rhs: " + rhs + " ]";
    }

    // Implementation methods
    //-------------------------------------------------------------------------
    private void init()
    {
        short type1 = lhs.getMatchType();
        short type2 = rhs.getMatchType();
        this.nodeType = ( type1 == type2 ) ? type1 : ANY_NODE;

        String name1 = lhs.getMatchesNodeName();
        String name2 = rhs.getMatchesNodeName();

        this.matchesNodeName = null;
        if ( name1 != null && name2 != null && name1.equals( name2 ) )
        {
            this.matchesNodeName = name1;
        }
    }
}