Java tutorial
/* * Copyright (C) 2005-2012 BetaCONCEPT Limited * * This file is part of Astroboa. * * Astroboa is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Astroboa is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with Astroboa. If not, see <http://www.gnu.org/licenses/>. */ package org.betaconceptframework.astroboa.engine.definition.xsom; import java.io.IOException; import java.net.URL; import org.apache.commons.lang.StringUtils; import org.betaconceptframework.astroboa.api.model.BetaConceptNamespaceConstants; import org.betaconceptframework.astroboa.configuration.W3CRelatedSchemaEntityResolver; import org.betaconceptframework.astroboa.util.CmsConstants; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; import org.xml.sax.SAXException; /** * Used to resolve imports from definition xsd files * and mainly to provide the right xsd definition file * for internal astroboa types * * @author Gregory Chomatas (gchomatas@betaconcept.com) * @author Savvas Triantafyllou (striantafyllou@betaconcept.com) * */ public class EntityResolverForBuiltInSchemas implements EntityResolver { private final Logger logger = LoggerFactory.getLogger(getClass()); private W3CRelatedSchemaEntityResolver w3cRelatedSchemaEntityResolver = new W3CRelatedSchemaEntityResolver(); private String builtInDefinitionSchemaHomeDir; public void setBuiltInDefinitionSchemaHomeDir(String builtInDefinitionSchemaHomeDir) { this.builtInDefinitionSchemaHomeDir = builtInDefinitionSchemaHomeDir; } public String getBuiltInDefinitionSchemaHomeDir() { return builtInDefinitionSchemaHomeDir; } @Override /** * According to XSOM library * By setting EntityResolver to XSOMParser, you can redirect <xs:include>s and <xs:import>s to different resources. * For imports, the namespace URI of the target schema is passed as the public ID, * and the absolutized value of the schemaLocation attribute will be passed as the system ID. */ public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException { if (publicId != null && publicId.startsWith(BetaConceptNamespaceConstants.ASTROBOA_SCHEMA_URI) && systemId != null) { try { String schemaFilename = systemId; //We are only interested in file name if (schemaFilename.contains(CmsConstants.FORWARD_SLASH)) { schemaFilename = StringUtils.substringAfterLast(systemId, CmsConstants.FORWARD_SLASH); } URL definitionFileURL = locateBuiltinDefinitionURL(schemaFilename); if (definitionFileURL != null) { InputSource is = new InputSource(definitionFileURL.openStream()); /* * SystemId is actual the path to the resource * although its content has been loaded to input source. * Provided value (sustemId) is not set because if in XSD file in the corresponding import's * schemaLocation contains only the schema filename, then XSOM parser will * consider it as a relative path and will prefix it with the correct absolute path. * * For example, in cases where two different schemas, located in two different directories (portal-1.0.xsd and basicText-1.0.xsd), * import schema astroboa-model-1.2.xsd, xs import will look like * * <xs:import namespace="http://www.betaconceptframework.org/schema/astroboa/model" schemaLocation="astroboa-model-1.2.xsd" /> * * When XSOM parser will try to load astroboa-model-1.2.xsd, it will append * schemaLocation with the path of the directory where each of the parent XSDs are located. * * SchemaLocation value refers to systemId and if it is provided in this input source, XSOM parser * will have two different instances of InputSource referring to the same xsd file (definitionFileURL), * having the same publiId (namespace) but different systemIds (appended schemaLocation). * * This situation causes XSOM parser to throw an exception when the second input source is loaded * complaining that it found the same type(s) defined already, which is true since as far as XSOM parser * concerns these input sources are not the same. * * To overcome this, we set as system id the URL of the XSD file which is the same * in both situations. */ is.setSystemId(definitionFileURL.toString()); is.setPublicId(publicId); if (systemId.startsWith(BetaConceptNamespaceConstants.ASTROBOA_SCHEMA_URI)) { logger.warn("Schema Location for XSD Schema " + schemaFilename + ", which contains built in Astroboa model, is not relative but absolute." + " Unless this absolute location really 'serves' XSD, there will be a problem " + " when importing XML which contain xml elements derived from this Schema If this location is not real, then you are advised to delete it and leave only" + "the schema file name. Nevertheless the contents of " + schemaFilename + " have been found internally and have been successfully loaded to Astroboa"); } return is; } } catch (Exception e) { throw new IOException(e); } } //Returning null allow XSD Parser to continue with default behavior //and will try to resolve entity using its own implementation return resolveXmlSchemaRelatedToW3C(publicId, systemId); } public URL locateBuiltinDefinitionURL(String schemaFilename) throws IOException, Exception { //Any other file will reside in /META-INF/builtin-definition-schemas-directory return loadDefinitionFile(builtInDefinitionSchemaHomeDir + CmsConstants.FORWARD_SLASH + schemaFilename); } public URL loadDefinitionFile(String absolutePath) throws Exception { return EntityResolverForBuiltInSchemas.class.getResource(absolutePath); } /** * Resolves Entities with the following properties * * publicId = http://www.w3.org/XML/1998/namespace * systemId = http://www.w3.org/2001/03/xml.xsd * * publicId=-//W3C//DTD XMLSCHEMA 200102//EN * systemId=http://www.w3.org/2001/03/XMLSchema.dtd * * publicId = -//W3C//DTD XMLSCHEMA 200102//EN * systemId = http://www.w3.org/2001/03/XMLSchema.dtd * * If above schemata are not reachable (probably due to a lack of Internet access), * they are loaded from the package * * @return * @throws IOException * @throws SAXException */ public InputSource resolveXmlSchemaRelatedToW3C(String publicId, String systemId) throws IOException, SAXException { return w3cRelatedSchemaEntityResolver.resolveEntity(publicId, systemId); } }