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/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
// ResolvingXMLFilter.java - An XMLFilter that performs catalog resolution
/*
* Copyright 2001-2004 The Apache Software Foundation or its licensors,
* as applicable.
*
* 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.xml.internal.resolver.tools;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.XMLFilterImpl;
import com.sun.org.apache.xml.internal.resolver.Catalog;
import com.sun.org.apache.xml.internal.resolver.CatalogManager;
import com.sun.org.apache.xml.internal.resolver.helpers.FileURL;
/**
* A SAX XMLFilter that performs catalog-based entity resolution.
*
* <p>This class implements a SAX XMLFilter that performs entity resolution
* using the CatalogResolver. The actual, underlying parser is obtained
* from a SAXParserFactory.</p>
* </p>
*
* @see CatalogResolver
* @see org.xml.sax.XMLFilter
*
* @author Norman Walsh
* <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM</a>
*
* @version 1.0
*/
public class ResolvingXMLFilter extends XMLFilterImpl {
/**
* Suppress explanatory message?
*
* @see #parse(InputSource)
*/
public static boolean suppressExplanation = false;
/** The manager for the underlying resolver. */
CatalogManager catalogManager = CatalogManager.getStaticManager();
/** The underlying catalog resolver. */
private CatalogResolver catalogResolver = null;
/** A separate resolver for oasis-xml-pi catalogs. */
private CatalogResolver piCatalogResolver = null;
/** Are we in the prolog? Is an oasis-xml-catalog PI valid now? */
private boolean allowXMLCatalogPI = false;
/** Has an oasis-xml-catalog PI been seen? */
private boolean oasisXMLCatalogPI = false;
/** The base URI of the input document, if known. */
private URL baseURL = null;
/** Construct an empty XML Filter with no parent. */
public ResolvingXMLFilter() {
super();
catalogResolver = new CatalogResolver(catalogManager);
}
/** Construct an XML filter with the specified parent. */
public ResolvingXMLFilter(XMLReader parent) {
super(parent);
catalogResolver = new CatalogResolver(catalogManager);
}
/** Construct an XML filter with the specified parent. */
public ResolvingXMLFilter(CatalogManager manager) {
super();
catalogManager = manager;
catalogResolver = new CatalogResolver(catalogManager);
}
/** Construct an XML filter with the specified parent. */
public ResolvingXMLFilter(XMLReader parent, CatalogManager manager) {
super(parent);
catalogManager = manager;
catalogResolver = new CatalogResolver(catalogManager);
}
/**
* Provide accessto the underlying Catalog.
*/
public Catalog getCatalog() {
return catalogResolver.getCatalog();
}
/**
* SAX XMLReader API.
*
* <p>Note that the JAXP 1.1ea2 parser crashes with an InternalError if
* it encounters a system identifier that appears to be a relative URI
* that begins with a slash. For example, the declaration:</p>
*
* <pre>
* &lt;!DOCTYPE book SYSTEM "/path/to/dtd/on/my/system/docbookx.dtd">
* </pre>
*
* <p>would cause such an error. As a convenience, this method catches
* that error and prints an explanation. (Unfortunately, it's not possible
* to identify the particular system identifier that causes the problem.)
* </p>
*
* <p>The underlying error is forwarded after printing the explanatory
* message. The message is only every printed once and if
* <code>suppressExplanation</code> is set to <code>false</code> before
* parsing, it will never be printed.</p>
*/
public void parse(InputSource input)
throws IOException, SAXException {
allowXMLCatalogPI = true;
setupBaseURI(input.getSystemId());
try {
super.parse(input);
} catch (InternalError ie) {
explain(input.getSystemId());
throw ie;
}
}
/** SAX XMLReader API.
*
* @see #parse(InputSource)
*/
public void parse(String systemId)
throws IOException, SAXException {
allowXMLCatalogPI = true;
setupBaseURI(systemId);
try {
super.parse(systemId);
} catch (InternalError ie) {
explain(systemId);
throw ie;
}
}
/**
* Implements the <code>resolveEntity</code> method
* for the SAX interface, using an underlying CatalogResolver
* to do the real work.
*/
public InputSource resolveEntity (String publicId, String systemId) {
allowXMLCatalogPI = false;
String resolved = catalogResolver.getResolvedEntity(publicId, systemId);
if (resolved == null && piCatalogResolver != null) {
resolved = piCatalogResolver.getResolvedEntity(publicId, systemId);
}
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) {
catalogManager.debug.message(1, "Failed to create InputSource", resolved);
return null;
}
} else {
return null;
}
}
/** SAX DTDHandler API.
*
* <p>Captured here only to detect the end of the prolog so that
* we can ignore subsequent oasis-xml-catalog PIs. Otherwise
* the events are just passed through.</p>
*/
public void notationDecl (String name, String publicId, String systemId)
throws SAXException {
allowXMLCatalogPI = false;
super.notationDecl(name,publicId,systemId);
}
/** SAX DTDHandler API.
*
* <p>Captured here only to detect the end of the prolog so that
* we can ignore subsequent oasis-xml-catalog PIs. Otherwise
* the events are just passed through.</p>
*/
public void unparsedEntityDecl (String name,
String publicId,
String systemId,
String notationName)
throws SAXException {
allowXMLCatalogPI = false;
super.unparsedEntityDecl (name, publicId, systemId, notationName);
}
/** SAX ContentHandler API.
*
* <p>Captured here only to detect the end of the prolog so that
* we can ignore subsequent oasis-xml-catalog PIs. Otherwise
* the events are just passed through.</p>
*/
public void startElement (String uri, String localName, String qName,
Attributes atts)
throws SAXException {
allowXMLCatalogPI = false;
super.startElement(uri,localName,qName,atts);
}
/** SAX ContentHandler API.
*
* <p>Detect and use the oasis-xml-catalog PI if it occurs.</p>
*/
public void processingInstruction(String target, String pidata)
throws SAXException {
if (target.equals("oasis-xml-catalog")) {
URL catalog = null;
String data = pidata;
int pos = data.indexOf("catalog=");
if (pos >= 0) {
data = data.substring(pos+8);
if (data.length() > 1) {
String quote = data.substring(0,1);
data = data.substring(1);
pos = data.indexOf(quote);
if (pos >= 0) {
data = data.substring(0, pos);
try {
if (baseURL != null) {
catalog = new URL(baseURL, data);
} else {
catalog = new URL(data);
}
} catch (MalformedURLException mue) {
// nevermind
}
}
}
}
if (allowXMLCatalogPI) {
if (catalogManager.getAllowOasisXMLCatalogPI()) {
catalogManager.debug.message(4,"oasis-xml-catalog PI", pidata);
if (catalog != null) {
try {
catalogManager.debug.message(4,"oasis-xml-catalog", catalog.toString());
oasisXMLCatalogPI = true;
if (piCatalogResolver == null) {
piCatalogResolver = new CatalogResolver(true);
}
piCatalogResolver.getCatalog().parseCatalog(catalog.toString());
} catch (Exception e) {
catalogManager.debug.message(3, "Exception parsing oasis-xml-catalog: "
+ catalog.toString());
}
} else {
catalogManager.debug.message(3, "PI oasis-xml-catalog unparseable: " + pidata);
}
} else {
catalogManager.debug.message(4,"PI oasis-xml-catalog ignored: " + pidata);
}
} else {
catalogManager.debug.message(3, "PI oasis-xml-catalog occurred in an invalid place: "
+ pidata);
}
} else {
super.processingInstruction(target, pidata);
}
}
/** Save the base URI of the document being parsed. */
private void setupBaseURI(String systemId) {
URL cwd = null;
try {
cwd = FileURL.makeURL("basename");
} catch (MalformedURLException mue) {
cwd = null;
}
try {
baseURL = new URL(systemId);
} catch (MalformedURLException mue) {
if (cwd != null) {
try {
baseURL = new URL(cwd, systemId);
} catch (MalformedURLException mue2) {
// give up
baseURL = null;
}
} else {
// give up
baseURL = null;
}
}
}
/** Provide one possible explanation for an InternalError. */
private void explain(String systemId) {
if (!suppressExplanation) {
System.out.println("XMLReader probably encountered bad URI in " + systemId);
System.out.println("For example, replace '/some/uri' with 'file:/some/uri'.");
}
suppressExplanation = true;
}
}