org.openide.xml.EntityCatalog Maven / Gradle / Ivy
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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 limitations
* under the License.
*/
package org.openide.xml;
import java.awt.EventQueue;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.openide.util.Lookup;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
/**
* Entity resolver resolving all entities registered by modules.
* Use {@link #getDefault} to get the master instance in system. Any parser working with
* unknown XML documents should use it to avoid unnecessary Internet
* connections.
*
* You can register your own instances via lookup to add to the resolver pool,
* but for reasons of performance and predictability during startup it is best to provide
* the entity (e.g. some DTD you define) as the contents of a file in
* the system filesystem, in the /xml/entities/ folder, where the file path
* beneath this folder is based on the public ID as follows:
*
* - US-ASCII alphanumeric characters and '_' are left as is.
*
- Spaces and various punctuation are converted to '_' (one per character).
*
- Initial '-//' is dropped.
*
- Final '//EN' is dropped.
*
- Exactly two forward slashes in a row are converted to one.
*
* Thus for example the public ID -//NetBeans//Entity Mapping Registration 1.0//EN
* would be looked for in the file /xml/entities/NetBeans/Entity_Mapping_Registration_1_0.
* Naturally this only works if you are defining a fixed number of entities.
* It is recommended that the entity file in /xml/entities/ also be given a file
* attribute named hint.originalPublicID with a string value giving the public ID.
* This permits {@code org.netbeans.modules.xml.catalog} to display the entry properly.
* @author Petr Kuzel
*/
public abstract class EntityCatalog implements EntityResolver {
/** Default constructor for subclasses (generally discouraged). */
protected EntityCatalog() {}
/**
* DOCTYPE public ID defining grammar used for entity registrations.
* XML files matching this ID produce an instance of {@code EntityCatalog},
* so could be registered under {@code Services}.
* @deprecated Better to register entities individually by layer as described in class documentation.
*/
@Deprecated
public static final String PUBLIC_ID = "-//NetBeans//Entity Mapping Registration 1.0//EN"; // NOI18N
private static EntityCatalog instance = new Forwarder();
/** Get a master entity catalog which can delegate to any others that have
* been registered via lookup.
*/
public static EntityCatalog getDefault() {
return instance;
}
/**
* This catalog is forwarding implementation.
*/
private static class Forwarder extends EntityCatalog {
private Lookup.Result result;
Forwarder() {
}
public @Override InputSource resolveEntity(String publicID, String systemID)
throws IOException, SAXException {
if (result == null) {
result = Lookup.getDefault().lookupResult(EntityCatalog.class);
}
for (EntityCatalog res : result.allInstances()) {
// using resolver's method because EntityCatalog extends EntityResolver
InputSource is = res.resolveEntity(publicID, systemID);
if (is != null) {
return is;
}
}
if (systemID != null && systemID.startsWith("http")) { // NOI18N
Logger.getLogger(EntityCatalog.class.getName()).log(
/* More of a problem when blocking EQ; cf. #157850: */
EventQueue.isDispatchThread() ? Level.WARNING : Level.FINE,
"No resolver found for {0}", systemID);
}
return null;
}
}
}