/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2005 The Apache Software Foundation.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.xerces.internal.dom;

import com.sun.org.apache.xerces.internal.impl.RevalidationHandler;

import com.sun.org.apache.xerces.internal.parsers.DOMParserImpl;

import com.sun.org.apache.xerces.internal.util.XMLChar;

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

import com.sun.org.apache.xml.internal.serialize.DOMSerializerImpl;

import org.w3c.dom.DOMException;

import org.w3c.dom.DOMImplementation;

import org.w3c.dom.Document;

import org.w3c.dom.DocumentType;

import org.w3c.dom.Element;

import org.w3c.dom.ls.LSParser;

import org.w3c.dom.ls.DOMImplementationLS;

import org.w3c.dom.ls.LSInput;

import org.w3c.dom.ls.LSOutput;

import org.w3c.dom.ls.LSSerializer;

/**

 * The DOMImplementation class is description of a particular

 * implementation of the Document Object Model. As such its data is

 * static, shared by all instances of this implementation.

 * <P>

 * The DOM API requires that it be a real object rather than static

 * methods. However, there's nothing that says it can't be a singleton,

 * so that's how I've implemented it.

 * <P>

 * This particular class, along with CoreDocumentImpl, supports the DOM

 * Core and Load/Save (Experimental). Optional modules are supported by

 * the more complete DOMImplementation class along with DocumentImpl.

 *

 * @xerces.internal

 *

 * @since PR-DOM-Level-1-19980818.

 */

public class CoreDOMImplementationImpl

        implements DOMImplementation, DOMImplementationLS {

        //

        // Data

        //

    // validators pool

    private static final int SIZE = 2;

    private RevalidationHandler validators[] = new RevalidationHandler[SIZE];

    private RevalidationHandler dtdValidators[] = new RevalidationHandler[SIZE];

    private int freeValidatorIndex = -1;

    private int freeDTDValidatorIndex = -1;

    private int currentSize = SIZE;

    // Document and doctype counter.  Used to assign order to documents and

    // doctypes without owners, on an demand basis.   Used for

    // compareDocumentPosition

    private int docAndDoctypeCounter = 0;

        // static

        /** Dom implementation singleton. */

        static CoreDOMImplementationImpl singleton =

                new CoreDOMImplementationImpl();

        //

        // Public methods

        //

        /** NON-DOM: Obtain and return the single shared object */

        public static DOMImplementation getDOMImplementation() {

                return singleton;

        }

        //

        // DOMImplementation methods

        //

        /**

         * Test if the DOM implementation supports a specific "feature" --

         * currently meaning language and level thereof.

         *

         * @param feature The package name of the feature to test.

         * In Level 1, supported values are "HTML" and "XML" (case-insensitive).

         * At this writing, com.sun.org.apache.xerces.internal.dom supports only XML.

         *

         * @param version The version number of the feature being tested.

         * This is interpreted as "Version of the DOM API supported for the

         * specified Feature", and in Level 1 should be "1.0"

         *

         * @return true iff this implementation is compatable with the specified

         * feature and version.

         */

        public boolean hasFeature(String feature, String version) {

            boolean anyVersion = version == null || version.length() == 0;

            // check if Xalan implementation is around and if yes report true for supporting

            // XPath API

            // if a plus sign "+" is prepended to any feature name, implementations

            // are considered in which the specified feature may not be directly

            // castable DOMImplementation.getFeature(feature, version). Without a

            // plus, only features whose interfaces are directly castable are considered.

            if ((feature.equalsIgnoreCase("+XPath"))

                && (anyVersion || version.equals("3.0"))) {

                try {

                    Class xpathClass = ObjectFactory.findProviderClass(

                        "com.sun.org.apache.xpath.internal.domapi.XPathEvaluatorImpl",

                        ObjectFactory.findClassLoader(), true);

                // Check if the DOM XPath implementation implements

                // the interface org.w3c.dom.XPathEvaluator

                Class interfaces[] = xpathClass.getInterfaces();

                for (int i = 0; i < interfaces.length; i++) {

                    if (interfaces[i].getName().equals(

                        "org.w3c.dom.xpath.XPathEvaluator")) {

                        return true;

                    }

                }

                } catch (Exception e) {

                    return false;

                }

                return true;

            }

            if (feature.startsWith("+")) {

                feature = feature.substring(1);

            }

            return (

                feature.equalsIgnoreCase("Core")

                    && (anyVersion

                        || version.equals("1.0")

                        || version.equals("2.0")

                        || version.equals("3.0")))

                        || (feature.equalsIgnoreCase("XML")

                    && (anyVersion

                        || version.equals("1.0")

                        || version.equals("2.0")

                        || version.equals("3.0")))

                        || (feature.equalsIgnoreCase("LS")

                    && (anyVersion || version.equals("3.0")));

        } // hasFeature(String,String):boolean

        /**

         * Introduced in DOM Level 2. <p>

         *

         * Creates an empty DocumentType node.

         *

         * @param qualifiedName The qualified name of the document type to be created.

         * @param publicID The document type public identifier.

         * @param systemID The document type system identifier.

         * @since WD-DOM-Level-2-19990923

         */

        public DocumentType createDocumentType( String qualifiedName,

                                    String publicID, String systemID) {

                // REVISIT: this might allow creation of invalid name for DOCTYPE

                //          xmlns prefix.

                //          also there is no way for a user to turn off error checking.

                checkQName(qualifiedName);

                return new DocumentTypeImpl(null, qualifiedName, publicID, systemID);

        }

    final void checkQName(String qname){

        int index = qname.indexOf(':');

        int lastIndex = qname.lastIndexOf(':');

        int length = qname.length();

        // it is an error for NCName to have more than one ':'

        // check if it is valid QName [Namespace in XML production 6]

        if (index == 0 || index == length - 1 || lastIndex != index) {

            String msg =

                DOMMessageFormatter.formatMessage(

                    DOMMessageFormatter.DOM_DOMAIN,

                    "NAMESPACE_ERR",

                    null);

            throw new DOMException(DOMException.NAMESPACE_ERR, msg);

        }

        int start = 0;

        // Namespace in XML production [6]

        if (index > 0) {

            // check that prefix is NCName

            if (!XMLChar.isNCNameStart(qname.charAt(start))) {

                String msg =

                    DOMMessageFormatter.formatMessage(

                        DOMMessageFormatter.DOM_DOMAIN,

                        "INVALID_CHARACTER_ERR",

                        null);

                throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);

            }

            for (int i = 1; i < index; i++) {

                if (!XMLChar.isNCName(qname.charAt(i))) {

                    String msg =

                        DOMMessageFormatter.formatMessage(

                            DOMMessageFormatter.DOM_DOMAIN,

                            "INVALID_CHARACTER_ERR",

                            null);

                    throw new DOMException(

                        DOMException.INVALID_CHARACTER_ERR,

                        msg);

                }

            }

            start = index + 1;

        }

        // check local part

        if (!XMLChar.isNCNameStart(qname.charAt(start))) {

            // REVISIT: add qname parameter to the message

            String msg =

                DOMMessageFormatter.formatMessage(

                    DOMMessageFormatter.DOM_DOMAIN,

                    "INVALID_CHARACTER_ERR",

                    null);

            throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);

        }

        for (int i = start + 1; i < length; i++) {

            if (!XMLChar.isNCName(qname.charAt(i))) {

                String msg =

                    DOMMessageFormatter.formatMessage(

                        DOMMessageFormatter.DOM_DOMAIN,

                        "INVALID_CHARACTER_ERR",

                        null);

                throw new DOMException(DOMException.INVALID_CHARACTER_ERR, msg);

            }

        }

    }

        /**

         * Introduced in DOM Level 2. <p>

         *

         * Creates an XML Document object of the specified type with its document

         * element.

         *

         * @param namespaceURI     The namespace URI of the document

         *                         element to create, or null.

         * @param qualifiedName    The qualified name of the document

         *                         element to create.

         * @param doctype          The type of document to be created or null.<p>

         *

         *                         When doctype is not null, its

         *                         Node.ownerDocument attribute is set to

         *                         the document being created.

         * @return Document        A new Document object.

         * @throws DOMException    WRONG_DOCUMENT_ERR: Raised if doctype has

         *                         already been used with a different document.

         * @since WD-DOM-Level-2-19990923

         */

        public Document createDocument(

                String namespaceURI,

                String qualifiedName,

                DocumentType doctype)

                throws DOMException {

                if (doctype != null && doctype.getOwnerDocument() != null) {

                        String msg =

                                DOMMessageFormatter.formatMessage(

                                        DOMMessageFormatter.DOM_DOMAIN,

                                        "WRONG_DOCUMENT_ERR",

                                        null);

                        throw new DOMException(DOMException.WRONG_DOCUMENT_ERR, msg);

                }

                CoreDocumentImpl doc = new CoreDocumentImpl(doctype);

                Element e = doc.createElementNS(namespaceURI, qualifiedName);

                doc.appendChild(e);

                return doc;

        }

        /**

         * DOM Level 3 WD - Experimental.

         */

        public Object getFeature(String feature, String version) {

            if (singleton.hasFeature(feature, version)) {

                if ((feature.equalsIgnoreCase("+XPath"))) {

                    try {

                        Class xpathClass = ObjectFactory.findProviderClass(

                            "com.sun.org.apache.xpath.internal.domapi.XPathEvaluatorImpl",

                            ObjectFactory.findClassLoader(), true);

                        // Check if the DOM XPath implementation implements

                        // the interface org.w3c.dom.XPathEvaluator

                        Class interfaces[] = xpathClass.getInterfaces();

                        for (int i = 0; i < interfaces.length; i++) {

                            if (interfaces[i].getName().equals(

                                "org.w3c.dom.xpath.XPathEvaluator")) {

                                return xpathClass.newInstance();

                            }

                        }

                    } catch (Exception e) {

                        return null;

                    }

                } else {

                    return singleton;

                }

            }

            return null;

        }

        // DOM L3 LS

        /**

         * DOM Level 3 LS CR - Experimental.

     * Create a new <code>LSParser</code>. The newly constructed parser may

     * then be configured by means of its <code>DOMConfiguration</code>

     * object, and used to parse documents by means of its <code>parse</code>

     *  method.

     * @param mode  The <code>mode</code> argument is either

     *   <code>MODE_SYNCHRONOUS</code> or <code>MODE_ASYNCHRONOUS</code>, if

     *   <code>mode</code> is <code>MODE_SYNCHRONOUS</code> then the

     *   <code>LSParser</code> that is created will operate in synchronous

     *   mode, if it's <code>MODE_ASYNCHRONOUS</code> then the

     *   <code>LSParser</code> that is created will operate in asynchronous

     *   mode.

     * @param schemaType  An absolute URI representing the type of the schema

     *   language used during the load of a <code>Document</code> using the

     *   newly created <code>LSParser</code>. Note that no lexical checking

     *   is done on the absolute URI. In order to create a

     *   <code>LSParser</code> for any kind of schema types (i.e. the

     *   LSParser will be free to use any schema found), use the value

     *   <code>null</code>.

     * <p ><b>Note:</b>    For W3C XML Schema [<a href='http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/'>XML Schema Part 1</a>]

     *   , applications must use the value

     *   <code>"http://www.w3.org/2001/XMLSchema"</code>. For XML DTD [<a href='http://www.w3.org/TR/2000/REC-xml-20001006'>XML 1.0</a>],

     *   applications must use the value

     *   <code>"http://www.w3.org/TR/REC-xml"</code>. Other Schema languages

     *   are outside the scope of the W3C and therefore should recommend an

     *   absolute URI in order to use this method.

     * @return  The newly created <code>LSParser</code> object. This

     *   <code>LSParser</code> is either synchronous or asynchronous

     *   depending on the value of the <code>mode</code> argument.

     * <p ><b>Note:</b>    By default, the newly created <code>LSParser</code>

     *    does not contain a <code>DOMErrorHandler</code>, i.e. the value of

     *   the "<a href='http://www.w3.org/TR/2003/WD-DOM-Level-3-Core-20030609/core.html#parameter-error-handler'>

     *   error-handler</a>" configuration parameter is <code>null</code>. However, implementations

     *   may provide a default error handler at creation time. In that case,

     *   the initial value of the <code>"error-handler"</code> configuration

     *   parameter on the new created <code>LSParser</code> contains a

     *   reference to the default error handler.

     * @exception DOMException

     *    NOT_SUPPORTED_ERR: Raised if the requested mode or schema type is

     *   not supported.

         */

        public LSParser createLSParser(short mode, String schemaType)

                throws DOMException {

                if (mode != DOMImplementationLS.MODE_SYNCHRONOUS || (schemaType !=null &&

                   !"http://www.w3.org/2001/XMLSchema".equals(schemaType) &&

                        !"http://www.w3.org/TR/REC-xml".equals(schemaType))) {

                        String msg =

                                DOMMessageFormatter.formatMessage(

                                        DOMMessageFormatter.DOM_DOMAIN,

                                        "NOT_SUPPORTED_ERR",

                                        null);

                        throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);

                }

                if (schemaType != null

                        && schemaType.equals("http://www.w3.org/TR/REC-xml")) {

                        return new DOMParserImpl(

                                "com.sun.org.apache.xerces.internal.parsers.DTDConfiguration",

                                schemaType);

                }

                else {

                        // create default parser configuration validating against XMLSchemas

                        return new DOMParserImpl(

                                "com.sun.org.apache.xerces.internal.parsers.XIncludeAwareParserConfiguration",

                                schemaType);

                }

        }

        /**

         * DOM Level 3 LS CR - Experimental.

         * Create a new <code>LSSerializer</code> object.

         * @return The newly created <code>LSSerializer</code> object.

         * <p ><b>Note:</b>    By default, the newly created

         * <code>LSSerializer</code> has no <code>DOMErrorHandler</code>,

         * i.e. the value of the <code>"error-handler"</code> configuration

         * parameter is <code>null</code>. However, implementations may

         * provide a default error handler at creation time. In that case, the

         * initial value of the <code>"error-handler"</code> configuration

         * parameter on the new created <code>LSSerializer</code> contains a

         * reference to the default error handler.

         */

        public LSSerializer createLSSerializer() {

        return new DOMSerializerImpl();

    }

        /**

         * DOM Level 3 LS CR - Experimental.

         * Create a new empty input source.

         * @return  The newly created input object.

         */

        public LSInput createLSInput() {

                return new DOMInputImpl();

        }

        //

        // Protected methods

        //

        /** NON-DOM: retrieve validator. */

        synchronized RevalidationHandler getValidator(String schemaType) {

                // REVISIT: implement retrieving DTD validator

        if (schemaType == XMLGrammarDescription.XML_SCHEMA) {

            // create new validator - we should not attempt

            // to restrict the number of validation handlers being

            // requested

            if(freeValidatorIndex < 0) {

                return (RevalidationHandler) (ObjectFactory

                            .newInstance(

                                "com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator",

                                ObjectFactory.findClassLoader(),

                                true));

            }

            // return first available validator

            RevalidationHandler val = validators[freeValidatorIndex];

            validators[freeValidatorIndex--] = null;

            return val;

        }

        else if(schemaType == XMLGrammarDescription.XML_DTD) {

            if(freeDTDValidatorIndex < 0) {

                return (RevalidationHandler) (ObjectFactory

                            .newInstance(

                                "com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator",

                                ObjectFactory.findClassLoader(),

                                true));

            }

            // return first available validator

            RevalidationHandler val = dtdValidators[freeDTDValidatorIndex];

            dtdValidators[freeDTDValidatorIndex--] = null;

            return val;

        }

        return null;

        }

        /** NON-DOM: release validator */

        synchronized void releaseValidator(String schemaType,

                                         RevalidationHandler validator) {

       // REVISIT: implement support for DTD validators as well

       if(schemaType == XMLGrammarDescription.XML_SCHEMA) {

           ++freeValidatorIndex;

           if (validators.length == freeValidatorIndex ){

                // resize size of the validators

                currentSize+=SIZE;

                RevalidationHandler newarray[] =  new RevalidationHandler[currentSize];

                System.arraycopy(validators, 0, newarray, 0, validators.length);

                validators = newarray;

           }

           validators[freeValidatorIndex]=validator;

       }

       else if(schemaType == XMLGrammarDescription.XML_DTD) {

           ++freeDTDValidatorIndex;

           if (dtdValidators.length == freeDTDValidatorIndex ){

                // resize size of the validators

                currentSize+=SIZE;

                RevalidationHandler newarray[] =  new RevalidationHandler[currentSize];

                System.arraycopy(dtdValidators, 0, newarray, 0, dtdValidators.length);

                dtdValidators = newarray;

           }

           dtdValidators[freeDTDValidatorIndex]=validator;

       }

        }

       /** NON-DOM:  increment document/doctype counter */

       protected synchronized int assignDocumentNumber() {

            return ++docAndDoctypeCounter;

       }

       /** NON-DOM:  increment document/doctype counter */

       protected synchronized int assignDocTypeNumber() {

            return ++docAndDoctypeCounter;

       }

    /* DOM Level 3 LS CR - Experimental.

     *

     * Create a new empty output destination object where

     * <code>LSOutput.characterStream</code>,

     * <code>LSOutput.byteStream</code>, <code>LSOutput.systemId</code>,

     * <code>LSOutput.encoding</code> are null.

     * @return  The newly created output object.

     */

       public LSOutput createLSOutput() {

           return new DOMOutputImpl();

       }

} // class DOMImplementationImpl