001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *      http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.oozie.service;
020
021import org.apache.hadoop.conf.Configuration;
022import org.apache.oozie.util.IOUtils;
023import org.apache.oozie.ErrorCode;
024import org.xml.sax.SAXException;
025
026import javax.xml.XMLConstants;
027import javax.xml.transform.stream.StreamSource;
028import javax.xml.validation.Schema;
029import javax.xml.validation.SchemaFactory;
030import java.io.IOException;
031import java.util.ArrayList;
032import java.util.List;
033
034/**
035 * Service that loads Oozie workflow definition schema and registered extension schemas.
036 */
037public class WorkflowSchemaService implements Service {
038
039    public static final String CONF_PREFIX = Service.CONF_PREFIX + "WorkflowSchemaService.";
040
041    public static final String CONF_EXT_SCHEMAS = CONF_PREFIX + "ext.schemas";
042
043    private Schema dagSchema;
044
045    private static final String OOZIE_WORKFLOW_XSD = "oozie-workflow-0.1.xsd";
046
047    private Schema loadSchema(Configuration conf) throws SAXException, IOException {
048        List<StreamSource> sources = new ArrayList<StreamSource>();
049        sources.add(new StreamSource(IOUtils.getResourceAsStream(OOZIE_WORKFLOW_XSD, -1)));
050        String[] schemas = conf.getStrings(CONF_EXT_SCHEMAS);
051        if (schemas != null) {
052            for (String schema : schemas) {
053                sources.add(new StreamSource(IOUtils.getResourceAsStream(schema, -1)));
054            }
055        }
056        SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
057        return factory.newSchema(sources.toArray(new StreamSource[sources.size()]));
058    }
059
060    /**
061     * Initialize the service.
062     *
063     * @param services services instance.
064     * @throws ServiceException thrown if the service could not be initialized.
065     */
066    public void init(Services services) throws ServiceException {
067        try {
068            dagSchema = loadSchema(services.getConf());
069        }
070        catch (SAXException ex) {
071            throw new ServiceException(ErrorCode.E0130, ex.getMessage(), ex);
072        }
073        catch (IOException ex) {
074            throw new ServiceException(ErrorCode.E0131, ex.getMessage(), ex);
075        }
076    }
077
078    /**
079     * Return the public interface of the service.
080     *
081     * @return {@link WorkflowSchemaService}.
082     */
083    public Class<? extends Service> getInterface() {
084        return WorkflowSchemaService.class;
085    }
086
087    /**
088     * Destroy the service.
089     */
090    public void destroy() {
091        dagSchema = null;
092    }
093
094    /**
095     * Return the schema for XML validation of application definitions.
096     *
097     * @return the schema for XML validation of application definitions.
098     */
099    public Schema getSchema() {
100        return dagSchema;
101    }
102
103}