/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2000-2002 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.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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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;

import com.sun.org.apache.xerces.internal.xni.grammars.XMLGrammarDescription;
import com.sun.org.apache.xerces.internal.xni.XMLResourceIdentifier;
import com.sun.org.apache.xerces.internal.xni.parser.XMLInputSource;

import com.sun.org.apache.xerces.internal.util.XMLResourceIdentifierImpl;
import java.util.Vector;

/*
 * All information specific to dTD grammars.  
 * 
 * @author Neil Graham, IBM
 * @version $Id: XMLDTDDescription.java,v 1.7 2003/01/07 22:46:53 sandygao Exp $
 */

public class XMLDTDDescription extends XMLResourceIdentifierImpl
        implements com.sun.org.apache.xerces.internal.xni.grammars.XMLDTDDescription {

    // Data

    // pieces of information needed to make this usable as a Grammar key
    // if we know the root of this grammar, here's its name:
    protected String fRootName = null;

    // if we don't know the root name, this stores all elements that
    // could serve; fPossibleRoots and fRootName cannot both be non-null
    protected Vector fPossibleRoots = null;

    // Constructors:
    public XMLDTDDescription(XMLResourceIdentifier id, String rootName) {
        this.setValues(id.getPublicId(), id.getLiteralSystemId(),
                id.getBaseSystemId(), id.getExpandedSystemId());
        this.fRootName = rootName;
        this.fPossibleRoots = null;
    } // init(XMLResourceIdentifier, String)

    public XMLDTDDescription(String publicId, String literalId,
                String baseId, String expandedId, String rootName) {
        this.setValues(publicId, literalId, baseId, expandedId);
        this.fRootName = rootName;
        this.fPossibleRoots = null;
    } // init(String, String, String, String, String)

    public XMLDTDDescription(XMLInputSource source) {
        this.setValues(source.getPublicId(), null,
                source.getBaseSystemId(), source.getSystemId());
        this.fRootName = null;
        this.fPossibleRoots = null;
    } // init(XMLInputSource)

    // XMLGrammarDescription methods

    public String getGrammarType () {
        return XMLGrammarDescription.XML_DTD;
    } // getGrammarType():  String

    // return the root name of this DTD
    // returns null if root name is unknown
    public String getRootName() {
        return fRootName;
    } // getRootName():  String

    // set the root name
    public void setRootName(String rootName) {
        fRootName = rootName;
        fPossibleRoots = null;
    }

    // set possible roots
    public void setPossibleRoots(Vector possibleRoots) {
        fPossibleRoots = possibleRoots;
    } 

    /**
     * Compares this grammar with the given grammar. Currently, we compare 
     * as follows:
     * - if grammar type not equal return false immediately
     * - try and find a common root name:
     *    - if both have roots, use them
     *    - else if one has a root, examine other's possible root's for a match;
     *    - else try all combinations
     *  - test fExpandedSystemId and fPublicId as above
     * 
     * @param desc The description of the grammar to be compared with
     * @return     True if they are equal, else false
     */
    public boolean equals(Object desc) {
        if(!(desc instanceof XMLGrammarDescription)) return false;
    	if (!getGrammarType().equals(((XMLGrammarDescription)desc).getGrammarType())) {
    	    return false;
    	}
        // assume it's a DTDDescription
        XMLDTDDescription dtdDesc = (XMLDTDDescription)desc;
        if(fRootName != null) {
            if((dtdDesc.fRootName) != null && !dtdDesc.fRootName.equals(fRootName)) {
                return false;
            } else if(dtdDesc.fPossibleRoots != null && !dtdDesc.fPossibleRoots.contains(fRootName)) {
                return false;
            }
        } else if(fPossibleRoots != null) {
            if(dtdDesc.fRootName != null) {
                if(!fPossibleRoots.contains(dtdDesc.fRootName)) { 
                    return false;
                }
            } else if(dtdDesc.fPossibleRoots == null) {
                return false;
            } else {
                boolean found = false;
                for(int i = 0; i<fPossibleRoots.size(); i++) {
                    String root = (String)fPossibleRoots.elementAt(i);
                    found = dtdDesc.fPossibleRoots.contains(root);
                    if(found) break;
                }
                if(!found) return false;
            }
        }
        // if we got this far we've got a root match... try other two fields,
        // since so many different DTD's have roots in common:
        if(fExpandedSystemId != null) {
            if(!fExpandedSystemId.equals(dtdDesc.fExpandedSystemId)) 
                return false;
        } 
        else if(dtdDesc.fExpandedSystemId != null)
            return false;
        if(fPublicId != null) {
            if(!fPublicId.equals(dtdDesc.fPublicId)) 
                return false;
        } 
        else if(dtdDesc.fPublicId != null)
            return false;
    	return true;
    }
    
    /**
     * Returns the hash code of this grammar
     * Because our .equals method is so complex, we just return a very
     * simple hash that might avoid calls to the equals method a bit...
     * @return The hash code
     */
    public int hashCode() {
        if(fExpandedSystemId != null)
            return fExpandedSystemId.hashCode();
        if(fPublicId != null)
            return fPublicId.hashCode();
        // give up; hope .equals can handle it:
        return 0;
    }
} // class XMLDTDDescription