/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.internal.xjc.reader.xmlschema.parser;

import java.util.HashSet;

import java.util.Set;

import java.util.Stack;

import javax.xml.namespace.QName;

import com.sun.tools.internal.xjc.reader.Const;

import com.sun.xml.internal.bind.v2.WellKnownNamespace;

import org.xml.sax.Attributes;

import org.xml.sax.ErrorHandler;

import org.xml.sax.Locator;

import org.xml.sax.SAXException;

import org.xml.sax.SAXParseException;

import org.xml.sax.helpers.XMLFilterImpl;

/**

 * Checks if binding declarations are placed where they are allowed.

 *

 * <p>

 *

 * <p>

 * our main checkpoint of misplaced customizations are in BGMBuilder.

 * There, we mark a customization whenever we use it. At the end of the

 * day, we look for unmarked customizations and raise errors for them.

 *

 * <p>

 * Between this approach and the JAXB spec 1.0 is a problem that

 * the spec allows/prohibits customizations at schema element level,

 * while BGMBuilder and XSOM works on schema component levels.

 *

 * <p>

 * For example, a property customization is allowed on a complex type

 * element. The spec team informed us that they would consider resolving

 * this discrepancy in favor of RI, but meanwhile we need to detect

 * errors correctly.

 *

 * <p>

 * This filter is implemented for this purpose.

 *

 *

 * <h2>Customization and allowed locations</h2>

 *

 * - globalBinding/schemaBinding

 *     schema

 *

 * - class

 *     complexType(*), modelGroupDecl, modelGroup, element

 *

 * - property

 *     attribute, element, any, modelGroup, modelGroupRef, complexType(*)

 *

 * - javaType

 *     simpleType(*)

 *

 * - typesafeEnumClass

 *     simpleType(*)

 *

 * - typesafeEnumMember

 *     simpleType(*), enumeration

 *

 * Components marked with '*' needs a check by this component

 * since more than one schema element corresponds to one schema component

 * of that type.

 *

 * <p>

 * element, and for complex types they are allowed only under the

 *

 * <p>

 * So the bottom line is that it would be suffice if we just make sure

 * that no customization will be attached under other elements of

 * simple types and complex types. Those are:

 *

 * - simpleType/restriction

 * - list

 * - union

 * - complexType/(simple or complex)Content

 * - complexType/(simple or complex)Content/(restriction of extension)

 *

 * @author

 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)

 */

public class CustomizationContextChecker extends XMLFilterImpl {

    /** Keep names of all the ancestor elements. */

    private final Stack<QName> elementNames = new Stack<QName>();

    private final ErrorHandler errorHandler;

    private Locator locator;

    /** Set of element names that cannot have JAXB customizations. */

    private static final Set<String> prohibitedSchemaElementNames = new HashSet<String>();

    /**

     * @param _errorHandler

     *      Detected errors will be sent to this object.

     */

    public CustomizationContextChecker( ErrorHandler _errorHandler ) {

        this.errorHandler = _errorHandler;

    }

    static {

        prohibitedSchemaElementNames.add("restriction");

        prohibitedSchemaElementNames.add("extension");

        prohibitedSchemaElementNames.add("simpleContent");

        prohibitedSchemaElementNames.add("complexContent");

        prohibitedSchemaElementNames.add("list");

        prohibitedSchemaElementNames.add("union");

    }

    /** Gets the stack top. */

    private QName top() {

        return elementNames.peek();

    }

    public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {

        QName newElement = new QName(namespaceURI,localName);

        if( newElement.getNamespaceURI().equals(Const.JAXB_NSURI)

         && top().getNamespaceURI().equals(WellKnownNamespace.XML_SCHEMA) ) {

            // we hit a JAXB customization. the stack top should be

            // <xs:appinfo>

            if( elementNames.size()>=3 ) {

                // the above statement checks if the following statement doesn't

                // cause an exception.

                QName schemaElement = elementNames.get( elementNames.size()-3 );

                if( prohibitedSchemaElementNames.contains(schemaElement.getLocalPart()) ) {

                    // the owner schema element is in the wanted list.

                    errorHandler.error( new SAXParseException(

                        Messages.format(

                            Messages.ERR_UNACKNOWLEDGED_CUSTOMIZATION,

                            localName ),

                        locator ) );

                }

            }

        }

        elementNames.push(newElement);

        super.startElement(namespaceURI, localName, qName, atts );

    }

    public void endElement(String namespaceURI, String localName, String qName)

        throws SAXException {

        super.endElement(namespaceURI, localName, qName);

        elementNames.pop();

    }

    public void setDocumentLocator(Locator locator) {

        super.setDocumentLocator(locator);

        this.locator = locator;

    }

}