Java tutorial
/* * 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.apache.cocoon.core.xml.impl; import java.io.File; import java.io.IOException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.xml.resolver.CatalogManager; import org.apache.xml.resolver.tools.CatalogResolver; import org.springframework.context.ResourceLoaderAware; import org.springframework.core.io.Resource; import org.springframework.core.io.ResourceLoader; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; import org.xml.sax.SAXException; /** * A component that uses catalogs for resolving entities. * This implementation uses the XML Entity and URI Resolvers from * http://xml.apache.org/commons/ * published by Norman Walsh. More information on the catalogs can be * found at * http://xml.apache.org/cocoon/userdocs/concepts/catalog.html * * @version $Id: DefaultEntityResolver.java 587751 2007-10-24 02:41:36Z vgritsenko $ * @since 2.2 */ public class DefaultEntityResolver implements EntityResolver, ResourceLoaderAware { /** By default we use the logger for this class. */ private Log logger = LogFactory.getLog(getClass()); public Log getLogger() { return this.logger; } public void setLogger(Log l) { this.logger = l; } /** * Correct resource uris. */ protected String correctUri(String uri) throws IOException { // if it is a file we have to recreate the url, // otherwise we get problems under windows with some file // references starting with "/DRIVELETTER" and some // just with "DRIVELETTER" if (uri.startsWith("file:")) { final File f = new File(uri.substring(5)); return f.toURL().toExternalForm(); } return uri; } /** The catalog manager */ protected CatalogManager catalogManager = new CatalogManager(); /** The catalog resolver */ protected CatalogResolver catalogResolver = new CatalogResolver(catalogManager); /** Verbosity level. */ protected Integer verbosity; protected String catalog = "WEB-INF/cocoon/entities/catalog"; protected String localCatalog; protected ResourceLoader resourceLoader; public Integer getVerbosity() { return verbosity; } public void setVerbosity(Integer verbosity) { this.verbosity = verbosity; } public String getCatalog() { return catalog; } public void setCatalog(String catalog) { this.catalog = catalog; } public String getLocalCatalog() { return localCatalog; } public void setLocalCatalog(String localCatalog) { this.localCatalog = localCatalog; } public void setResourceLoader(ResourceLoader loader) { this.resourceLoader = loader; } public ResourceLoader getResourceLoader() { return resourceLoader; } /** * Set the configuration. Load the system catalog and apply any * parameters that may have been set using the public setter methods. */ public void init() throws Exception { // Over-ride debug level that is set by CatalogManager.properties if (this.verbosity != null) { if (this.getLogger().isDebugEnabled()) { this.getLogger().debug("Setting Catalog resolver verbosity level to " + this.verbosity); } this.catalogManager.setVerbosity(this.verbosity.intValue()); } // Load the built-in catalog if (this.catalog == null) { this.getLogger().warn("No default catalog defined."); } else { this.parseCatalog(this.catalog); } // Load a single additional local catalog if (this.localCatalog != null) { this.parseCatalog(this.localCatalog); } } /** * Parse a catalog */ protected void parseCatalog(String uri) { if (this.getLogger().isDebugEnabled()) { this.getLogger().debug("Additional Catalog is " + uri); } final Resource resource = this.resourceLoader.getResource(uri); try { this.catalogResolver.getCatalog().parseCatalog(this.correctUri(resource.getURL().toExternalForm())); } catch (Exception e) { this.getLogger().warn("Could not get Catalog file. Trying again: " + uri, e); // try it again try { this.catalogResolver.getCatalog().parseCatalog("text/plain", resource.getInputStream()); } catch (Exception ex) { this.getLogger().warn("Could not get Catalog file: " + uri, ex); } } } /** * Allow the application to resolve external entities. * * <p>The Parser will call this method before opening any external * entity except the top-level document entity (including the * external DTD subset, external entities referenced within the * DTD, and external entities referenced within the document * element): the application may request that the parser resolve * the entity itself, that it use an alternative URI, or that it * use an entirely different input source.</p> * * <p>Application writers can use this method to redirect external * system identifiers to secure and/or local URIs, to look up * public identifiers in a catalogue, or to read an entity from a * database or other input source (including, for example, a dialog * box).</p> * * <p>If the system identifier is a URL, the SAX parser must * resolve it fully before reporting it to the application.</p> * * @param publicId The public identifier of the external entity * being referenced, or null if none was supplied. * @param systemId The system identifier of the external entity * being referenced. * @return An InputSource object describing the new input source, * or null to request that the parser open a regular * URI connection to the system identifier. * @exception org.xml.sax.SAXException Any SAX exception, possibly * wrapping another exception. * @exception java.io.IOException A Java-specific IO exception, * possibly the result of creating a new InputStream * or Reader for the InputSource. * @see org.xml.sax.InputSource */ public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException { InputSource altInputSource = this.catalogResolver.resolveEntity(publicId, systemId); if (altInputSource != null) { if (this.getLogger().isDebugEnabled()) { this.getLogger().debug("Resolved catalog entity: " + publicId + " " + altInputSource.getSystemId()); } } return altInputSource; } }