src/org/apache/xerces/impl/xs/models/XSCMLeaf.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999,2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
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 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
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 * 5. Products derived from this software may not be called "Apache",
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 * 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 Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.xerces.impl.xs.models;

import org.apache.xerces.impl.dtd.models.CMNode;
import org.apache.xerces.impl.dtd.models.CMStateSet;
import org.apache.xerces.impl.xs.XSElementDecl;
import org.apache.xerces.impl.xs.XSParticleDecl;
import org.apache.xerces.impl.xs.XSWildcardDecl;

/**
 * Content model leaf node.
 *
 * @author Neil Graham, IBM
 * @version $$
 */
public class XSCMLeaf
    extends CMNode {

    //
    // Data
    //

    /** This is the leaf particle. */
    private XSParticleDecl fLeaf = null;

    /**
     * Part of the algorithm to convert a regex directly to a DFA
     * numbers each leaf sequentially. If its -1, that means its an
     * epsilon node. Zero and greater are non-epsilon positions.
     */
    private int fPosition = -1;

    //
    // Constructors
    //

    /** Constructs a content model leaf. */
    public XSCMLeaf(XSParticleDecl leaf, int position)  {
        super(leaf.fType);

        // Store the element index and position
        fLeaf = leaf;
        fPosition = position;
    }

    /** Constructs a content model leaf. */
    public XSCMLeaf(XSParticleDecl leaf)  {
        this(leaf, -1);
    }

    //
    // Package methods
    //

    final XSParticleDecl getLeaf() {
        return fLeaf;
    }

    final int getPosition() {
        return fPosition;
    }

    final void setPosition(int newPosition) {
        fPosition = newPosition;
    }

    //
    // CMNode methods
    //

    // package

    public boolean isNullable() {
        // Leaf nodes are never nullable unless its an epsilon node
        return (fPosition == -1);
    }

    public String toString() {
        StringBuffer strRet = new StringBuffer(fLeaf.fValue.toString());
        if (fPosition >= 0) {
            strRet.append
            (
                " (Pos:"
                + new Integer(fPosition).toString()
                + ")"
            );
        }
        return strRet.toString();
    }

    // protected

    protected void calcFirstPos(CMStateSet toSet) {
        // If we are an epsilon node, then the first pos is an empty set
        if (fPosition == -1)
            toSet.zeroBits();

        // Otherwise, its just the one bit of our position
        else
            toSet.setBit(fPosition);
    }

    protected void calcLastPos(CMStateSet toSet) {
        // If we are an epsilon node, then the last pos is an empty set
        if (fPosition == -1)
            toSet.zeroBits();

        // Otherwise, its just the one bit of our position
        else
            toSet.setBit(fPosition);
    }

} // class XSCMLeaf