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/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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

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

import java.io.InputStream;

import java.io.IOException;

import java.io.Reader;

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

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

import com.sun.org.apache.xerces.internal.xni.XMLResourceIdentifier;

import com.sun.org.apache.xerces.internal.xni.XNIException;

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

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

import org.xml.sax.ext.EntityResolver2;

import org.xml.sax.InputSource;

import org.xml.sax.SAXException;

/**

 * <p>This class wraps a SAX entity resolver (EntityResolver2) in an XNI entity resolver.</p>

 *

 * @author Michael Glavassevich, IBM

 *

 */

public class EntityResolver2Wrapper

    implements ExternalSubsetResolver {

    //

    // Data

    //

    /** An instance of SAX2 Extensions 1.1's EntityResolver2. */

    protected EntityResolver2 fEntityResolver;

    //

    // Constructors

    //

    /** Default constructor. */

    public EntityResolver2Wrapper() {}

    /**

     * <p>Creates a new instance wrapping the given SAX entity resolver.</p>

     *

     * @param entityResolver the SAX entity resolver to wrap

     */

    public EntityResolver2Wrapper(EntityResolver2 entityResolver) {

        setEntityResolver(entityResolver);

    } // <init>(EntityResolver2)

    //

    // Public methods

    //

    /**

     * <p>Sets the SAX entity resolver wrapped by this object.</p>

     *

     * @param entityResolver the SAX entity resolver to wrap

     */

    public void setEntityResolver(EntityResolver2 entityResolver) {

        fEntityResolver = entityResolver;

    } // setEntityResolver(EntityResolver2)

    /**

     * <p>Returns the SAX entity resolver wrapped by this object.</p>

     *

     * @return the SAX entity resolver wrapped by this object

     */

    public EntityResolver2 getEntityResolver() {

        return fEntityResolver;

    } // getEntityResolver():EntityResolver2

    //

    // ExternalSubsetResolver methods

    //

    /**

     * <p>Locates an external subset for documents which do not explicitly

     * provide one. If no external subset is provided, this method should

     * return <code>null</code>.</p>

     *

     * @param grammarDescription a description of the DTD

     *

     * @throws XNIException Thrown on general error.

     * @throws IOException  Thrown if resolved entity stream cannot be

     *                      opened or some other i/o error occurs.

     */

    public XMLInputSource getExternalSubset(XMLDTDDescription grammarDescription)

            throws XNIException, IOException {

        if (fEntityResolver != null) {

            String name = grammarDescription.getRootName();

            String baseURI = grammarDescription.getBaseSystemId();

            // Resolve using EntityResolver2

            try {

                InputSource inputSource = fEntityResolver.getExternalSubset(name, baseURI);

                return (inputSource != null) ? createXMLInputSource(inputSource, baseURI) : null;

            }

            // error resolving external subset

            catch (SAXException e) {

                Exception ex = e.getException();

                if (ex == null) {

                    ex = e;

                }

                throw new XNIException(ex);

            }

        }

        // unable to resolve external subset

        return null;

    } // getExternalSubset(XMLDTDDescription):XMLInputSource

    //

    // XMLEntityResolver methods

    //

    /**

     * Resolves an external parsed entity. If the entity cannot be

     * resolved, this method should return null.

     *

     * @param resourceIdentifier contains the physical co-ordinates of the resource to be resolved

     *

     * @throws XNIException Thrown on general error.

     * @throws IOException  Thrown if resolved entity stream cannot be

     *                      opened or some other i/o error occurs.

     */

    public XMLInputSource resolveEntity(XMLResourceIdentifier resourceIdentifier)

            throws XNIException, IOException {

        if (fEntityResolver != null) {

            String pubId = resourceIdentifier.getPublicId();

            String sysId = resourceIdentifier.getLiteralSystemId();

            String baseURI = resourceIdentifier.getBaseSystemId();

            String name = null;

            if (resourceIdentifier instanceof XMLDTDDescription) {

                name = "[dtd]";

            }

            else if (resourceIdentifier instanceof XMLEntityDescription) {

                name = ((XMLEntityDescription) resourceIdentifier).getEntityName();

            }

            // When both pubId and sysId are null, the user's entity resolver

            // can do nothing about it. We'd better not bother calling it.

            // This happens when the resourceIdentifier is a GrammarDescription,

            // which describes a schema grammar of some namespace, but without

            // any schema location hint. -Sg

            if (pubId == null && sysId == null) {

                return null;

            }

            // Resolve using EntityResolver2

            try {

                InputSource inputSource =

                    fEntityResolver.resolveEntity(name, pubId, baseURI, sysId);

                return (inputSource != null) ? createXMLInputSource(inputSource, baseURI) : null;

            }

            // error resolving entity

            catch (SAXException e) {

                Exception ex = e.getException();

                if (ex == null) {

                    ex = e;

                }

                throw new XNIException(ex);

            }

        }

        // unable to resolve entity

        return null;

    } // resolveEntity(XMLResourceIdentifier):XMLInputSource

    /**

     * Creates an XMLInputSource from a SAX InputSource.

     */

    private XMLInputSource createXMLInputSource(InputSource source, String baseURI) {

        String publicId = source.getPublicId();

        String systemId = source.getSystemId();

        String baseSystemId = baseURI;

        InputStream byteStream = source.getByteStream();

        Reader charStream = source.getCharacterStream();

        String encoding = source.getEncoding();

        XMLInputSource xmlInputSource =

            new XMLInputSource(publicId, systemId, baseSystemId, false);

        xmlInputSource.setByteStream(byteStream);

        xmlInputSource.setCharacterStream(charStream);

        xmlInputSource.setEncoding(encoding);

        return xmlInputSource;

    } // createXMLInputSource(InputSource,String):XMLInputSource

} // class EntityResolver2Wrapper