/*
 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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
 * limitations under the License.
 */

package com.sun.org.apache.xml.internal.resolver.helpers;

import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.URIResolver;
import javax.xml.transform.sax.SAXSource;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;

A simple bootstrapping resolver.
This class is used as the entity resolver when reading XML Catalogs.
It searches for the OASIS XML Catalog DTD, Relax NG Grammar and W3C XML Schema
as resources (e.g., in the resolver jar file).
If you have your own DTDs or schemas, you can extend this class and
set the BootstrapResolver in your CatalogManager.
Author:
Norman Walsh
Norman.Walsh@Sun.COM
See Also:
CatalogManager/**
 * A simple bootstrapping resolver.
 *
 * <p>This class is used as the entity resolver when reading XML Catalogs.
 * It searches for the OASIS XML Catalog DTD, Relax NG Grammar and W3C XML Schema
 * as resources (e.g., in the resolver jar file).</p>
 *
 * <p>If you have your own DTDs or schemas, you can extend this class and
 * set the BootstrapResolver in your CatalogManager.</p>
 *
 * @see com.sun.org.apache.xml.internal.resolver.CatalogManager
 *
 * @author Norman Walsh
 * <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a>
 *
 */
public class BootstrapResolver implements EntityResolver, URIResolver {
  
URI of the W3C XML Schema for OASIS XML Catalog files. /** URI of the W3C XML Schema for OASIS XML Catalog files. */
  public static final String xmlCatalogXSD = "http://www.oasis-open.org/committees/entity/release/1.0/catalog.xsd";

  
URI of the RELAX NG Grammar for OASIS XML Catalog files. /** URI of the RELAX NG Grammar for OASIS XML Catalog files. */
  public static final String xmlCatalogRNG = "http://www.oasis-open.org/committees/entity/release/1.0/catalog.rng";

  
Public identifier for OASIS XML Catalog files. /** Public identifier for OASIS XML Catalog files. */
  public static final String xmlCatalogPubId = "-//OASIS//DTD XML Catalogs V1.0//EN";

  
System identifier for OASIS XML Catalog files. /** System identifier for OASIS XML Catalog files. */
  public static final String xmlCatalogSysId = "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd";

  
Public identifier for legacy Apache XCatalog files.  There is no official system identifier for XCatalog files. /** Public identifier for legacy Apache XCatalog files.  There is no official system identifier for XCatalog files. */
  public static final String xCatalogPubId = "-//DTD XCatalog//EN";

  
Private hash used for public identifiers. /** Private hash used for public identifiers. */
  private final Map<String, String> publicMap = new HashMap<>();

  
Private hash used for system identifiers. /** Private hash used for system identifiers. */
  private final Map<String, String> systemMap = new HashMap<>();

  
Private hash used for URIs. /** Private hash used for URIs. */
  private final Map<String, String> uriMap = new HashMap<>();

  
Constructor. /** Constructor. */
  public BootstrapResolver() {
    URL url = this.getClass().getResource("/com/sun/org/apache/xml/internal/resolver/etc/catalog.dtd");
    if (url != null) {
      publicMap.put(xmlCatalogPubId, url.toString());
      systemMap.put(xmlCatalogSysId, url.toString());
    }

    url = this.getClass().getResource("/com/sun/org/apache/xml/internal/resolver/etc/catalog.rng");
    if (url != null) {
      uriMap.put(xmlCatalogRNG, url.toString());
    }

    url = this.getClass().getResource("/com/sun/org/apache/xml/internal/resolver/etc/catalog.xsd");
    if (url != null) {
      uriMap.put(xmlCatalogXSD, url.toString());
    }

    url = this.getClass().getResource("/com/sun/org/apache/xml/internal/resolver/etc/xcatalog.dtd");
    if (url != null) {
      publicMap.put(xCatalogPubId, url.toString());
    }
  }

  
SAX resolveEntity API. /** SAX resolveEntity API. */
  public InputSource resolveEntity (String publicId, String systemId) {
    String resolved = null;

    if (systemId != null && systemMap.containsKey(systemId)) {
      resolved = systemMap.get(systemId);
    } else if (publicId != null && publicMap.containsKey(publicId)) {
      resolved = publicMap.get(publicId);
    }

    if (resolved != null) {
      try {
        InputSource iSource = new InputSource(resolved);
        iSource.setPublicId(publicId);

        // Ideally this method would not attempt to open the
        // InputStream, but there is a bug (in Xerces, at least)
        // that causes the parser to mistakenly open the wrong
        // system identifier if the returned InputSource does
        // not have a byteStream.
        //
        // It could be argued that we still shouldn't do this here,
        // but since the purpose of calling the entityResolver is
        // almost certainly to open the input stream, it seems to
        // do little harm.
        //
        URL url = new URL(resolved);
        InputStream iStream = url.openStream();
        iSource.setByteStream(iStream);

        return iSource;
      } catch (Exception e) {
        // FIXME: silently fail?
        return null;
      }
    }

    return null;
  }

  
Transformer resolve API. /** Transformer resolve API. */
  public Source resolve(String href, String base)
    throws TransformerException {

    String uri = href;
    String fragment = null;
    int hashPos = href.indexOf("#");
    if (hashPos >= 0) {
      uri = href.substring(0, hashPos);
      fragment = href.substring(hashPos+1);
    }

    String result = null;
    if (href != null && uriMap.containsKey(href)) {
      result = uriMap.get(href);
    }

    if (result == null) {
      try {
        URL url = null;

        if (base==null) {
          url = new URL(uri);
          result = url.toString();
        } else {
          URL baseURL = new URL(base);
          url = (href.length()==0 ? baseURL : new URL(baseURL, uri));
          result = url.toString();
        }
      } catch (java.net.MalformedURLException mue) {
        // try to make an absolute URI from the current base
        String absBase = makeAbsolute(base);
        if (!absBase.equals(base)) {
          // don't bother if the absBase isn't different!
          return resolve(href, absBase);
        } else {
          throw new TransformerException("Malformed URL "
                                         + href + "(base " + base + ")",
                                         mue);
        }
      }
    }

    SAXSource source = new SAXSource();
    source.setInputSource(new InputSource(result));
    return source;
  }

  
Attempt to construct an absolute URI /** Attempt to construct an absolute URI */
  private String makeAbsolute(String uri) {
    if (uri == null) {
      uri = "";
    }

    try {
      URL url = new URL(uri);
      return url.toString();
    } catch (MalformedURLException mue) {
      try {
        URL fileURL = FileURL.makeURL(uri);
        return fileURL.toString();
      } catch (MalformedURLException mue2) {
        // bail
        return uri;
      }
    }
  }
}