substitutiongrouphandler.java

来自「JAVA的一些源码 JAVA2 STANDARD EDITION DEVELO」· Java 代码 · 共 358 行 · 第 1/2 页

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 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.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    distribution.
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 * 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
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 * 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) 2001, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
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package com.sun.org.apache.xerces.internal.impl.xs;

import com.sun.org.apache.xerces.internal.xs.XSConstants;
import com.sun.org.apache.xerces.internal.xs.XSTypeDefinition;
import com.sun.org.apache.xerces.internal.xni.QName;
import java.util.Hashtable;
import java.util.Vector;

/**
 * To store and validate information about substitutionGroup
 *
 * @author Sandy Gao, IBM
 *
 * @version $Id: SubstitutionGroupHandler.java,v 1.14 2003/11/11 20:14:58 sandygao Exp $
 */
public class SubstitutionGroupHandler {

    // grammar resolver
    XSGrammarBucket fGrammarBucket;

    /**
     * Default constructor
     */
    public SubstitutionGroupHandler(XSGrammarBucket grammarBucket) {
        fGrammarBucket = grammarBucket;
    }

    // 3.9.4 Element Sequence Locally Valid (Particle) 2.3.3
    // check whether one element decl matches an element with the given qname
    public XSElementDecl getMatchingElemDecl(QName element, XSElementDecl exemplar) {
        if (element.localpart == exemplar.fName &&
            element.uri == exemplar.fTargetNamespace) {
            return exemplar;
        }

        // if the exemplar is not a global element decl, then it's not possible
        // to be substituted by another element.
        if (exemplar.fScope != XSConstants.SCOPE_GLOBAL)
            return null;

        // if the decl blocks substitution, return false
        if ((exemplar.fBlock & XSConstants.DERIVATION_SUBSTITUTION) != 0)
            return null;

        // get grammar of the element
        SchemaGrammar sGrammar = fGrammarBucket.getGrammar(element.uri);
        if (sGrammar == null)
            return null;

        // get the decl for the element
        XSElementDecl eDecl = sGrammar.getGlobalElementDecl(element.localpart);
        if (eDecl == null)
            return null;

        // and check by using substitutionGroup information
        if (substitutionGroupOK(eDecl, exemplar, exemplar.fBlock))
            return eDecl;

        return null;
    }

    // 3.3.6 Substitution Group OK (Transitive)
    // check whether element can substitute exemplar
    protected boolean substitutionGroupOK(XSElementDecl element, XSElementDecl exemplar, short blockingConstraint) {
        // For an element declaration (call it D) to be validly substitutable for another element declaration (call it C) subject to a blocking constraint (a subset of {substitution, extension, restriction}, the value of a {disallowed substitutions}) one of the following must be true:
        // 1. D and C are the same element declaration.
        if (element == exemplar)
            return true;
        
        // 2 All of the following must be true:
        // 2.1 The blocking constraint does not contain substitution.
        if ((blockingConstraint & XSConstants.DERIVATION_SUBSTITUTION) != 0)
            return false;

        // 2.2 There is a chain of {substitution group affiliation}s from D to C, that is, either D's {substitution group affiliation} is C, or D's {substitution group affiliation}'s {substitution group affiliation} is C, or . . .
        XSElementDecl subGroup = element.fSubGroup;
        while (subGroup != null && subGroup != exemplar) {
            subGroup = subGroup.fSubGroup;
        }

        if (subGroup == null)
            return false;

        // 2.3 The set of all {derivation method}s involved in the derivation of D's {type definition} from C's {type definition} does not intersect with the union of the blocking constraint, C's {prohibited substitutions} (if C is complex, otherwise the empty set) and the {prohibited substitutions} (respectively the empty set) of any intermediate {type definition}s in the derivation of D's {type definition} from C's {type definition}.
        // prepare the combination of {derivation method} and
        // {disallowed substitution}
        short devMethod = 0, blockConstraint = blockingConstraint;

        // element.fType should be derived from exemplar.fType
        // add derivation methods of derived types to devMethod;
        // add block of base types to blockConstraint.
        XSTypeDefinition type = element.fType;
        while (type != exemplar.fType && type != SchemaGrammar.fAnyType) {
            if (type.getTypeCategory() == XSTypeDefinition.COMPLEX_TYPE)
                devMethod |= ((XSComplexTypeDecl)type).fDerivedBy;
            else
                devMethod |= XSConstants.DERIVATION_RESTRICTION;
            type = type.getBaseType();
            // type == null means the current type is anySimpleType,
            // whose base type should be anyType
            if (type == null)
                type = SchemaGrammar.fAnyType;
            if (type.getTypeCategory() == XSTypeDefinition.COMPLEX_TYPE)
                blockConstraint |= ((XSComplexTypeDecl)type).fBlock;
        }
        if (type != exemplar.fType)
            return false;
        
        if ((devMethod & blockConstraint) != 0)
            return false;

        return true;
    }

    // check whether element is in exemplar's substitution group
    public boolean inSubstitutionGroup(XSElementDecl element, XSElementDecl exemplar) {
        // [Definition:]  Every element declaration (call this HEAD) in the {element declarations} of a schema defines a substitution group, a subset of those {element declarations}, as follows:
        // Define PSG, the potential substitution group for HEAD, as follows:
        // 1 The element declaration itself is in PSG;
        // 2 PSG is closed with respect to {substitution group affiliation}, that is, if any element declaration in the {element declarations} has a {substitution group affiliation} in PSG, then it is also in PSG itself.
        // HEAD's actual substitution group is then the set consisting of each member of PSG such that all of the following must be true:
        // 1 Its {abstract} is false.