Java example source code file (Resolver.java)
The Resolver.java Java example source code
/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
// Resolver.java - Represents an extension of OASIS Open Catalog files.
/*
* 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;
import java.io.IOException;
import java.io.InputStream;
import java.io.FileNotFoundException;
import java.util.Enumeration;
import java.util.Vector;
import java.net.URL;
import java.net.URLConnection;
import java.net.MalformedURLException;
import javax.xml.parsers.SAXParserFactory;
import com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl;
import com.sun.org.apache.xerces.internal.utils.SecuritySupport;
import com.sun.org.apache.xml.internal.resolver.readers.SAXCatalogReader;
import com.sun.org.apache.xml.internal.resolver.readers.OASISXMLCatalogReader;
import com.sun.org.apache.xml.internal.resolver.readers.TR9401CatalogReader;
/**
* An extension to OASIS Open Catalog files, this class supports
* suffix-based matching and an external RFC2483 resolver.
*
* @see Catalog
*
* @author Norman Walsh
* <a href="mailto:Norman.Walsh@Sun.COM">Norman.Walsh@Sun.COM
*
* @version 1.0
*/
public class Resolver extends Catalog {
/**
* The URISUFFIX Catalog Entry type.
*
* <p>URI suffix entries match URIs that end in a specified suffix.
*/
public static final int URISUFFIX = CatalogEntry.addEntryType("URISUFFIX", 2);
/**
* The SYSTEMSUFFIX Catalog Entry type.
*
* <p>System suffix entries match system identifiers that end in a
* specified suffix.</p>
*/
public static final int SYSTEMSUFFIX = CatalogEntry.addEntryType("SYSTEMSUFFIX", 2);
/**
* The RESOLVER Catalog Entry type.
*
* <p>A hook for providing support for web-based backup resolvers.
*/
public static final int RESOLVER = CatalogEntry.addEntryType("RESOLVER", 1);
/**
* The SYSTEMREVERSE Catalog Entry type.
*
* <p>This is a bit of a hack. There's no actual SYSTEMREVERSE entry,
* but this entry type is used to indicate that a reverse lookup is
* being performed. (This allows the Resolver to implement
* RFC2483 I2N and I2NS.)
*/
public static final int SYSTEMREVERSE
= CatalogEntry.addEntryType("SYSTEMREVERSE", 1);
/**
* Setup readers.
*/
public void setupReaders() {
SAXParserFactory spf = catalogManager.useServicesMechanism() ?
SAXParserFactory.newInstance() : new SAXParserFactoryImpl();
spf.setNamespaceAware(true);
spf.setValidating(false);
SAXCatalogReader saxReader = new SAXCatalogReader(spf);
saxReader.setCatalogParser(null, "XMLCatalog",
"com.sun.org.apache.xml.internal.resolver.readers.XCatalogReader");
saxReader.setCatalogParser(OASISXMLCatalogReader.namespaceName,
"catalog",
"com.sun.org.apache.xml.internal.resolver.readers.ExtendedXMLCatalogReader");
addReader("application/xml", saxReader);
TR9401CatalogReader textReader = new TR9401CatalogReader();
addReader("text/plain", textReader);
}
/**
* Cleanup and process a Catalog entry.
*
* <p>This method processes each Catalog entry, changing mapped
* relative system identifiers into absolute ones (based on the current
* base URI), and maintaining other information about the current
* catalog.</p>
*
* @param entry The CatalogEntry to process.
*/
public void addEntry(CatalogEntry entry) {
int type = entry.getEntryType();
if (type == URISUFFIX) {
String suffix = normalizeURI(entry.getEntryArg(0));
String fsi = makeAbsolute(normalizeURI(entry.getEntryArg(1)));
entry.setEntryArg(1, fsi);
catalogManager.debug.message(4, "URISUFFIX", suffix, fsi);
} else if (type == SYSTEMSUFFIX) {
String suffix = normalizeURI(entry.getEntryArg(0));
String fsi = makeAbsolute(normalizeURI(entry.getEntryArg(1)));
entry.setEntryArg(1, fsi);
catalogManager.debug.message(4, "SYSTEMSUFFIX", suffix, fsi);
}
super.addEntry(entry);
}
/**
* Return the applicable URI.
*
* <p>If a URI entry exists in the Catalog
* for the URI specified, return the mapped value.</p>
*
* <p>In the Resolver (as opposed to the Catalog) class, if the
* URI isn't found by the usual algorithm, URISUFFIX entries are
* considered.</p>
*
* <p>URI comparison is case sensitive.
*
* @param uri The URI to locate in the catalog.
*
* @return The resolved URI.
*
* @throws MalformedURLException The system identifier of a
* subordinate catalog cannot be turned into a valid URL.
* @throws IOException Error reading subordinate catalog file.
*/
public String resolveURI(String uri)
throws MalformedURLException, IOException {
String resolved = super.resolveURI(uri);
if (resolved != null) {
return resolved;
}
Enumeration en = catalogEntries.elements();
while (en.hasMoreElements()) {
CatalogEntry e = (CatalogEntry) en.nextElement();
if (e.getEntryType() == RESOLVER) {
resolved = resolveExternalSystem(uri, e.getEntryArg(0));
if (resolved != null) {
return resolved;
}
} else if (e.getEntryType() == URISUFFIX) {
String suffix = e.getEntryArg(0);
String result = e.getEntryArg(1);
if (suffix.length() <= uri.length()
&& uri.substring(uri.length()-suffix.length()).equals(suffix)) {
return result;
}
}
}
// Otherwise, look in the subordinate catalogs
return resolveSubordinateCatalogs(Catalog.URI,
null,
null,
uri);
}
/**
* Return the applicable SYSTEM system identifier, resorting
* to external RESOLVERs if necessary.
*
* <p>If a SYSTEM entry exists in the Catalog
* for the system ID specified, return the mapped value.</p>
*
* <p>In the Resolver (as opposed to the Catalog) class, if the
* URI isn't found by the usual algorithm, SYSTEMSUFFIX entries are
* considered.</p>
*
* <p>On Windows-based operating systems, the comparison between
* the system identifier provided and the SYSTEM entries in the
* Catalog is case-insensitive.</p>
*
* @param systemId The system ID to locate in the catalog.
*
* @return The system identifier to use for systemId.
*
* @throws MalformedURLException The formal system identifier of a
* subordinate catalog cannot be turned into a valid URL.
* @throws IOException Error reading subordinate catalog file.
*/
public String resolveSystem(String systemId)
throws MalformedURLException, IOException {
String resolved = super.resolveSystem(systemId);
if (resolved != null) {
return resolved;
}
Enumeration en = catalogEntries.elements();
while (en.hasMoreElements()) {
CatalogEntry e = (CatalogEntry) en.nextElement();
if (e.getEntryType() == RESOLVER) {
resolved = resolveExternalSystem(systemId, e.getEntryArg(0));
if (resolved != null) {
return resolved;
}
} else if (e.getEntryType() == SYSTEMSUFFIX) {
String suffix = e.getEntryArg(0);
String result = e.getEntryArg(1);
if (suffix.length() <= systemId.length()
&& systemId.substring(systemId.length()-suffix.length()).equals(suffix)) {
return result;
}
}
}
return resolveSubordinateCatalogs(Catalog.SYSTEM,
null,
null,
systemId);
}
/**
* Return the applicable PUBLIC or SYSTEM identifier, resorting
* to external resolvers if necessary.
*
* <p>This method searches the Catalog and returns the system
* identifier specified for the given system or
* public identifiers. If
* no appropriate PUBLIC or SYSTEM entry is found in the Catalog,
* null is returned.</p>
*
* <p>Note that a system or public identifier in the current catalog
* (or subordinate catalogs) will be used in preference to an
* external resolver. Further, if a systemId is present, the external
* resolver(s) will be queried for that before the publicId.</p>
*
* @param publicId The public identifier to locate in the catalog.
* Public identifiers are normalized before comparison.
* @param systemId The nominal system identifier for the entity
* in question (as provided in the source document).
*
* @throws MalformedURLException The formal system identifier of a
* subordinate catalog cannot be turned into a valid URL.
* @throws IOException Error reading subordinate catalog file.
*
* @return The system identifier to use.
* Note that the nominal system identifier is not returned if a
* match is not found in the catalog, instead null is returned
* to indicate that no match was found.
*/
public String resolvePublic(String publicId, String systemId)
throws MalformedURLException, IOException {
String resolved = super.resolvePublic(publicId, systemId);
if (resolved != null) {
return resolved;
}
Enumeration en = catalogEntries.elements();
while (en.hasMoreElements()) {
CatalogEntry e = (CatalogEntry) en.nextElement();
if (e.getEntryType() == RESOLVER) {
if (systemId != null) {
resolved = resolveExternalSystem(systemId,
e.getEntryArg(0));
if (resolved != null) {
return resolved;
}
}
resolved = resolveExternalPublic(publicId, e.getEntryArg(0));
if (resolved != null) {
return resolved;
}
}
}
return resolveSubordinateCatalogs(Catalog.PUBLIC,
null,
publicId,
systemId);
}
/**
* Query an external RFC2483 resolver for a system identifier.
*
* @param systemId The system ID to locate.
* @param resolver The name of the resolver to use.
*
* @return The system identifier to use for the systemId.
*/
protected String resolveExternalSystem(String systemId, String resolver)
throws MalformedURLException, IOException {
Resolver r = queryResolver(resolver, "i2l", systemId, null);
if (r != null) {
return r.resolveSystem(systemId);
} else {
return null;
}
}
/**
* Query an external RFC2483 resolver for a public identifier.
*
* @param publicId The system ID to locate.
* @param resolver The name of the resolver to use.
*
* @return The system identifier to use for the systemId.
*/
protected String resolveExternalPublic(String publicId, String resolver)
throws MalformedURLException, IOException {
Resolver r = queryResolver(resolver, "fpi2l", publicId, null);
if (r != null) {
return r.resolvePublic(publicId, null);
} else {
return null;
}
}
/**
* Query an external RFC2483 resolver.
*
* @param resolver The URL of the RFC2483 resolver.
* @param command The command to send the resolver.
* @param arg1 The first argument to the resolver.
* @param arg2 The second argument to the resolver, usually null.
*
* @return The Resolver constructed.
*/
protected Resolver queryResolver(String resolver,
String command,
String arg1,
String arg2) {
InputStream iStream = null;
String RFC2483 = resolver + "?command=" + command
+ "&format=tr9401&uri=" + arg1
+ "&uri2=" + arg2;
String line = null;
try {
URL url = new URL(RFC2483);
URLConnection urlCon = url.openConnection();
urlCon.setUseCaches(false);
Resolver r = (Resolver) newCatalog();
String cType = urlCon.getContentType();
// I don't care about the character set or subtype
if (cType.indexOf(";") > 0) {
cType = cType.substring(0, cType.indexOf(";"));
}
r.parseCatalog(cType, urlCon.getInputStream());
return r;
} catch (CatalogException cex) {
if (cex.getExceptionType() == CatalogException.UNPARSEABLE) {
catalogManager.debug.message(1, "Unparseable catalog: " + RFC2483);
} else if (cex.getExceptionType()
== CatalogException.UNKNOWN_FORMAT) {
catalogManager.debug.message(1, "Unknown catalog format: " + RFC2483);
}
return null;
} catch (MalformedURLException mue) {
catalogManager.debug.message(1, "Malformed resolver URL: " + RFC2483);
return null;
} catch (IOException ie) {
catalogManager.debug.message(1, "I/O Exception opening resolver: " + RFC2483);
return null;
}
}
/**
* Append two vectors, returning the result.
*
* @param vec The first vector
* @param appvec The vector to be appended
* @return The vector vec, with appvec's elements appended to it
*/
private Vector appendVector(Vector vec, Vector appvec) {
if (appvec != null) {
for (int count = 0; count < appvec.size(); count++) {
vec.addElement(appvec.elementAt(count));
}
}
return vec;
}
/**
* Find the URNs for a given system identifier in all catalogs.
*
* @param systemId The system ID to locate.
*
* @return A vector of URNs that map to the systemId.
*/
public Vector resolveAllSystemReverse(String systemId)
throws MalformedURLException, IOException {
Vector resolved = new Vector();
// If there's a SYSTEM entry in this catalog, use it
if (systemId != null) {
Vector localResolved = resolveLocalSystemReverse(systemId);
resolved = appendVector(resolved, localResolved);
}
// Otherwise, look in the subordinate catalogs
Vector subResolved = resolveAllSubordinateCatalogs(SYSTEMREVERSE,
null,
null,
systemId);
return appendVector(resolved, subResolved);
}
/**
* Find the URN for a given system identifier.
*
* @param systemId The system ID to locate.
*
* @return A (single) URN that maps to the systemId.
*/
public String resolveSystemReverse(String systemId)
throws MalformedURLException, IOException {
Vector resolved = resolveAllSystemReverse(systemId);
if (resolved != null && resolved.size() > 0) {
return (String) resolved.elementAt(0);
} else {
return null;
}
}
/**
* Return the applicable SYSTEM system identifiers.
*
* <p>If one or more SYSTEM entries exists in the Catalog
* for the system ID specified, return the mapped values.</p>
*
* <p>The caller is responsible for doing any necessary
* normalization of the system identifier before calling
* this method. For example, a relative system identifier in
* a document might be converted to an absolute system identifier
* before attempting to resolve it.</p>
*
* <p>Note that this function will force all subordinate catalogs
* to be loaded.</p>
*
* <p>On Windows-based operating systems, the comparison between
* the system identifier provided and the SYSTEM entries in the
* Catalog is case-insensitive.</p>
*
* @param systemId The system ID to locate in the catalog.
*
* @return The system identifier to use for the notation.
*
* @throws MalformedURLException The formal system identifier of a
* subordinate catalog cannot be turned into a valid URL.
* @throws IOException Error reading subordinate catalog file.
*/
public Vector resolveAllSystem(String systemId)
throws MalformedURLException, IOException {
Vector resolutions = new Vector();
// If there are SYSTEM entries in this catalog, start with them
if (systemId != null) {
Vector localResolutions = resolveAllLocalSystem(systemId);
resolutions = appendVector(resolutions, localResolutions);
}
// Then look in the subordinate catalogs
Vector subResolutions = resolveAllSubordinateCatalogs(SYSTEM,
null,
null,
systemId);
resolutions = appendVector(resolutions, subResolutions);
if (resolutions.size() > 0) {
return resolutions;
} else {
return null;
}
}
/**
* Return all applicable SYSTEM system identifiers in this
* catalog.
*
* <p>If one or more SYSTEM entries exists in the catalog file
* for the system ID specified, return the mapped values.</p>
*
* @param systemId The system ID to locate in the catalog
*
* @return A vector of the mapped system identifiers or null
*/
private Vector resolveAllLocalSystem(String systemId) {
Vector map = new Vector();
String osname = SecuritySupport.getSystemProperty("os.name");
boolean windows = (osname.indexOf("Windows") >= 0);
Enumeration en = catalogEntries.elements();
while (en.hasMoreElements()) {
CatalogEntry e = (CatalogEntry) en.nextElement();
if (e.getEntryType() == SYSTEM
&& (e.getEntryArg(0).equals(systemId)
|| (windows
&& e.getEntryArg(0).equalsIgnoreCase(systemId)))) {
map.addElement(e.getEntryArg(1));
}
}
if (map.size() == 0) {
return null;
} else {
return map;
}
}
/**
* Find the URNs for a given system identifier in the current catalog.
*
* @param systemId The system ID to locate.
*
* @return A vector of URNs that map to the systemId.
*/
private Vector resolveLocalSystemReverse(String systemId) {
Vector map = new Vector();
String osname = SecuritySupport.getSystemProperty("os.name");
boolean windows = (osname.indexOf("Windows") >= 0);
Enumeration en = catalogEntries.elements();
while (en.hasMoreElements()) {
CatalogEntry e = (CatalogEntry) en.nextElement();
if (e.getEntryType() == SYSTEM
&& (e.getEntryArg(1).equals(systemId)
|| (windows
&& e.getEntryArg(1).equalsIgnoreCase(systemId)))) {
map.addElement(e.getEntryArg(0));
}
}
if (map.size() == 0) {
return null;
} else {
return map;
}
}
/**
* Search the subordinate catalogs, in order, looking for all
* match.
*
* <p>This method searches the Catalog and returns all of the system
* identifiers specified for the given entity type with the given
* name, public, and system identifiers. In some contexts, these
* may be null.</p>
*
* @param entityType The CatalogEntry type for which this query is
* being conducted. This is necessary in order to do the approprate
* query on a subordinate catalog.
* @param entityName The name of the entity being searched for, if
* appropriate.
* @param publicId The public identifier of the entity in question
* (as provided in the source document).
* @param systemId The nominal system identifier for the entity
* in question (as provided in the source document).
*
* @throws MalformedURLException The formal system identifier of a
* delegated catalog cannot be turned into a valid URL.
* @throws IOException Error reading delegated catalog file.
*
* @return The system identifier to use.
* Note that the nominal system identifier is not returned if a
* match is not found in the catalog, instead null is returned
* to indicate that no match was found.
*/
private synchronized Vector resolveAllSubordinateCatalogs(int entityType,
String entityName,
String publicId,
String systemId)
throws MalformedURLException, IOException {
Vector resolutions = new Vector();
for (int catPos = 0; catPos < catalogs.size(); catPos++) {
Resolver c = null;
try {
c = (Resolver) catalogs.elementAt(catPos);
} catch (ClassCastException e) {
String catfile = (String) catalogs.elementAt(catPos);
c = (Resolver) newCatalog();
try {
c.parseCatalog(catfile);
} catch (MalformedURLException mue) {
catalogManager.debug.message(1, "Malformed Catalog URL", catfile);
} catch (FileNotFoundException fnfe) {
catalogManager.debug.message(1, "Failed to load catalog, file not found",
catfile);
} catch (IOException ioe) {
catalogManager.debug.message(1, "Failed to load catalog, I/O error", catfile);
}
catalogs.setElementAt(c, catPos);
}
String resolved = null;
// Ok, now what are we supposed to call here?
if (entityType == DOCTYPE) {
resolved = c.resolveDoctype(entityName,
publicId,
systemId);
if (resolved != null) {
// Only find one DOCTYPE resolution
resolutions.addElement(resolved);
return resolutions;
}
} else if (entityType == DOCUMENT) {
resolved = c.resolveDocument();
if (resolved != null) {
// Only find one DOCUMENT resolution
resolutions.addElement(resolved);
return resolutions;
}
} else if (entityType == ENTITY) {
resolved = c.resolveEntity(entityName,
publicId,
systemId);
if (resolved != null) {
// Only find one ENTITY resolution
resolutions.addElement(resolved);
return resolutions;
}
} else if (entityType == NOTATION) {
resolved = c.resolveNotation(entityName,
publicId,
systemId);
if (resolved != null) {
// Only find one NOTATION resolution
resolutions.addElement(resolved);
return resolutions;
}
} else if (entityType == PUBLIC) {
resolved = c.resolvePublic(publicId, systemId);
if (resolved != null) {
// Only find one PUBLIC resolution
resolutions.addElement(resolved);
return resolutions;
}
} else if (entityType == SYSTEM) {
Vector localResolutions = c.resolveAllSystem(systemId);
resolutions = appendVector(resolutions, localResolutions);
break;
} else if (entityType == SYSTEMREVERSE) {
Vector localResolutions = c.resolveAllSystemReverse(systemId);
resolutions = appendVector(resolutions, localResolutions);
}
}
if (resolutions != null) {
return resolutions;
} else {
return null;
}
}
}
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