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 */
018package org.apache.oozie.service;
019
020import org.apache.hadoop.conf.Configuration;
021import org.apache.oozie.util.IOUtils;
022import org.apache.oozie.ErrorCode;
023import org.xml.sax.SAXException;
024
025import javax.xml.XMLConstants;
026import javax.xml.transform.stream.StreamSource;
027import javax.xml.validation.Schema;
028import javax.xml.validation.SchemaFactory;
029import java.io.IOException;
030import java.util.ArrayList;
031import java.util.List;
032
033/**
034 * Service that loads Oozie workflow definition schema and registered extension schemas.
035 */
036public class WorkflowSchemaService implements Service {
037
038    public static final String CONF_PREFIX = Service.CONF_PREFIX + "WorkflowSchemaService.";
039
040    public static final String CONF_EXT_SCHEMAS = CONF_PREFIX + "ext.schemas";
041
042    private Schema dagSchema;
043
044    private static final String OOZIE_WORKFLOW_XSD = "oozie-workflow-0.1.xsd";
045
046    private Schema loadSchema(Configuration conf) throws SAXException, IOException {
047        List<StreamSource> sources = new ArrayList<StreamSource>();
048        sources.add(new StreamSource(IOUtils.getResourceAsStream(OOZIE_WORKFLOW_XSD, -1)));
049        String[] schemas = conf.getStrings(CONF_EXT_SCHEMAS);
050        if (schemas != null) {
051            for (String schema : schemas) {
052                sources.add(new StreamSource(IOUtils.getResourceAsStream(schema, -1)));
053            }
054        }
055        SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
056        return factory.newSchema(sources.toArray(new StreamSource[sources.size()]));
057    }
058
059    /**
060     * Initialize the service.
061     *
062     * @param services services instance.
063     * @throws ServiceException thrown if the service could not be initialized.
064     */
065    public void init(Services services) throws ServiceException {
066        try {
067            dagSchema = loadSchema(services.getConf());
068        }
069        catch (SAXException ex) {
070            throw new ServiceException(ErrorCode.E0130, ex.getMessage(), ex);
071        }
072        catch (IOException ex) {
073            throw new ServiceException(ErrorCode.E0131, ex.getMessage(), ex);
074        }
075    }
076
077    /**
078     * Return the public interface of the service.
079     *
080     * @return {@link WorkflowSchemaService}.
081     */
082    public Class<? extends Service> getInterface() {
083        return WorkflowSchemaService.class;
084    }
085
086    /**
087     * Destroy the service.
088     */
089    public void destroy() {
090        dagSchema = null;
091    }
092
093    /**
094     * Return the schema for XML validation of application definitions.
095     *
096     * @return the schema for XML validation of application definitions.
097     */
098    public Schema getSchema() {
099        return dagSchema;
100    }
101
102}