package com.icl.saxon.pattern;
import com.icl.saxon.Context;
import com.icl.saxon.om.*;
import com.icl.saxon.expr.XPathException;

/**
* A pattern formed as the union (or) of two other patterns
*/

public class UnionPattern extends Pattern {

    protected Pattern p1, p2;
    private short nodeType = NodeInfo.NODE;

    /**
    * Constructor
    * @param p1 the left-hand operand
    * @param p2 the right-hand operand
    */

    public UnionPattern(Pattern p1, Pattern p2) {
        this.p1 = p1;
        this.p2 = p2;
        if (p1.getNodeType()==p2.getNodeType()) nodeType = p1.getNodeType();
    }

    /**
    * Simplify the pattern: perform any context-independent optimisations
    */

    public Pattern simplify() throws XPathException {
        return new UnionPattern(p1.simplify(), p2.simplify());
    }

	/**
	* Set the original text
	*/
	
	public void setOriginalText(String pattern) {
		this.originalText = pattern;
		p1.setOriginalText(pattern);
		p2.setOriginalText(pattern);
	}

    /**
    * Determine if the supplied node matches the pattern
    * @e the node to be compared
    * @return true if the node matches either of the operand patterns
    */

    public boolean matches(NodeInfo e, Context c) throws XPathException {
        return p1.matches(e, c) || p2.matches(e, c);
    }

    /**
    * Determine the types of nodes to which this pattern applies. Used for optimisation.
    * For patterns that match nodes of several types, return Node.NODE
    * @return the type of node matched by this pattern. e.g. Node.ELEMENT or Node.TEXT
    */

    public short getNodeType() {
        return nodeType;
    }

    /**
    * Get the LHS of the union
    */

    public Pattern getLHS() {
        return p1;
    }

    /**
    * Get the RHS of the union
    */

    public Pattern getRHS() {
        return p2;
    }

}

//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/ 
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License. 
//
// The Original Code is: all this file. 
//
// The Initial Developer of the Original Code is
// Michael Kay of International Computers Limited (mhkay@iclway.co.uk).
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved. 
//
// Contributor(s): none. 
//