src/org/apache/xerces/impl/xs/identity/Field.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001 The Apache Software Foundation.  
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * 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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 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
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 * ====================================================================
 *
 * 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/>.
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package org.apache.xerces.impl.xs.identity;

import org.apache.xerces.impl.dv.XSSimpleType;
import org.apache.xerces.impl.xpath.*;
import org.apache.xerces.util.SymbolTable;
import org.apache.xerces.xni.NamespaceContext;

import org.xml.sax.SAXException;

/**
 * Schema identity constraint field.
 *
 * @author Andy Clark, IBM
 * @version $Id$
 */
public class Field {

    //
    // Data
    //

    /** Field XPath. */
    protected Field.XPath fXPath;

    /** Datatype. */
    // Unfortunately, a Field may conceivably match values of varying
    // datatypes.  Hence, this member no longer makes sense; see the IDValue class.
    // protected XSSimpleType fXSSimpleType;

    /** Identity constraint. */
    protected IdentityConstraint fIdentityConstraint;

    // whether this field can be matched; used to catch instance documents
    // that try and match a field several times in the same scope.
    protected boolean mayMatch = true;

    //
    // Constructors
    //

    /** Constructs a field. */
    public Field(Field.XPath xpath, 
                 IdentityConstraint identityConstraint) {
        fXPath = xpath;
        fIdentityConstraint = identityConstraint;
    } // <init>(Field.XPath,IdentityConstraint)

    //
    // Public methods
    //

    // sets mayMatch
    public void setMayMatch(boolean b) {
        mayMatch = b;
    } // setMayMatch(boolean);
    
    // returns mayMatch
    public boolean mayMatch() {
        return mayMatch;
    } // mayMatch():boolean
    
    /** Returns the field XPath. */
    public org.apache.xerces.impl.xpath.XPath getXPath() {
        return fXPath;
    } // getXPath():org.apache.xerces.impl.v1.schema.identity.XPath

    /** Returns the identity constraint. */
    public IdentityConstraint getIdentityConstraint() {
        return fIdentityConstraint;
    } // getIdentityConstraint():IdentityConstraint

    // factory method

    /** Creates a field matcher. */
    public XPathMatcher createMatcher(ValueStore store) {
        return new Field.Matcher(fXPath, store);
    } // createMatcher(ValueStore):XPathMatcher

    //
    // Object methods
    //

    /** Returns a string representation of this object. */
    public String toString() {
        return fXPath.toString();
    } // toString():String

    //
    // Classes
    //

    /**
     * Field XPath.
     *
     * @author Andy Clark, IBM
     */
    public static class XPath
        extends org.apache.xerces.impl.xpath.XPath {

        //
        // Constructors
        //

        /** Constructs a field XPath expression. */
        public XPath(String xpath, 
                     SymbolTable symbolTable,
                     NamespaceContext context) throws XPathException {
            // NOTE: We have to prefix the field XPath with "./" in
            //       order to handle selectors such as "@attr" that 
            //       select the attribute because the fields could be
            //       relative to the selector element. -Ac
			//       Unless xpath starts with a descendant node -Achille Fokoue
            //      ... or a / or a . - NG
			super(((xpath.trim().startsWith("/") ||xpath.trim().startsWith("."))?
				    xpath:"./"+xpath), 
                  symbolTable, context);
			
        } // <init>(String,SymbolTable,NamespacesContext)

    } // class XPath

    /**
     * Field matcher.
     *
     * @author Andy Clark, IBM
     */
    protected class Matcher
        extends XPathMatcher {

        //
        // Data
        //

        /** Value store for data values. */
        protected ValueStore fStore;

        //
        // Constructors
        //

        /** Constructs a field matcher. */
        public Matcher(Field.XPath xpath, ValueStore store) {
            super(xpath, true, null);
            fStore = store;
        } // <init>(Field.XPath,ValueStore)

        //
        // XPathHandler methods
        //

        /**
         * This method is called when the XPath handler matches the
         * XPath expression.
         */
        protected void matched(String content, XSSimpleType val, boolean isNil) {
            super.matched(content, val, isNil);
            if(isNil) {
                fStore.reportNilError(fIdentityConstraint);
            }
            fStore.addValue(Field.this, new IDValue(content, val));
            // once we've stored the value for this field, we set the mayMatch
            // member to false so that, in the same scope, we don't match any more
            // values (and throw an error instead).
            mayMatch = false;
        } // matched(String)

    } // class Matcher

} // class Field