cmnode.java

java1.6众多例子参考

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2002 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
 *    the documentation and/or other materials provided with the
 *    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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 * 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 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 com.sun.org.apache.xerces.internal.impl.dtd.models;

/**
 * A content model node.
 * 
 * @xerces.internal
 *
 * @version $Id: CMNode.java,v 1.2 2005/08/16 22:53:45 jeffsuttor Exp $
 */
public abstract class CMNode
{
    // -------------------------------------------------------------------
    //  Constructors
    // -------------------------------------------------------------------
    public CMNode(int type) 
    {
        fType = type;
    }


    // -------------------------------------------------------------------
    //  Package, abstract methods
    // -------------------------------------------------------------------
    // made this public so it could be implemented and used outside this package -neilg.
    public abstract boolean isNullable() ;


    // -------------------------------------------------------------------
    //  Package final methods
    // -------------------------------------------------------------------
    public final int type()
    {
        return fType;
    }

    // made this public so it could be implemented and used outside this package -neilg.
    public final CMStateSet firstPos() 
    {
        if (fFirstPos == null)
        {
            fFirstPos = new CMStateSet(fMaxStates);
            calcFirstPos(fFirstPos);
        }
        return fFirstPos;
    }

    // made this public so it could be implemented and used outside this package -neilg.
    public final CMStateSet lastPos() 
    {
        if (fLastPos == null)
        {
            fLastPos = new CMStateSet(fMaxStates);
            calcLastPos(fLastPos);
        }
        return fLastPos;
    }

    final void setFollowPos(CMStateSet setToAdopt)
    {
        fFollowPos = setToAdopt;
    }

    public final void setMaxStates(int maxStates)
    {
        fMaxStates = maxStates;
    }

    /**
     * Allows the user to set arbitrary data on this content model
     * node. This is used by the a{n,m} optimization that runs
     * in constant space.
     */
    public void setUserData(Object userData) {
        fUserData = userData;
    }
    
    /**
     * Allows the user to get arbitrary data set on this content 
     * model node. This is used by the a{n,m} optimization that runs
     * in constant space.
     */
    public Object getUserData() {
        return fUserData;
    }

    // -------------------------------------------------------------------
    //  Protected, abstract methods
    // -------------------------------------------------------------------
    protected abstract void calcFirstPos(CMStateSet toSet) ;

    protected abstract void calcLastPos(CMStateSet toSet) ;


    // -------------------------------------------------------------------
    //  Private data members
    //
    //  fType
    //      The type of node. This indicates whether its a leaf or an
    //      operation. Though we also do derived classes for these types,
    //      it is too expensive to use runtime typing to find this out.
    //      This is one of the ContentSpecNode.NODE_XXX types.
    //
    //  fFirstPos
    //      The set of NFA states that represent the entry states of this
    //      node in the DFA.
    //
    //  fFollowPos
    //      The set of NFA states that can be gotten to from from this
    //      node in the DFA.
    //
    //  fLastPos
    //      The set of NFA states that represent the final states of this
    //      node in the DFA.
    //
    //  fMaxStates
    //      The maximum number of states that the NFA has, which means the
    //      max number of NFA states that have to be traced in the state
    //      sets during the building of the DFA. Its unfortunate that it
    //      has to be stored redundantly, but we need to fault in the
    //      state set members and they have to be sized to this size. We
    //      init to to -1 so it will cause an error if its used without
    //      being initialized.
    // -------------------------------------------------------------------
    private int         fType;
    private CMStateSet  fFirstPos   = null;
    private CMStateSet  fFollowPos  = null;
    private CMStateSet  fLastPos    = null;
    private int         fMaxStates  = -1;
    private Object      fUserData   = null;
};