DelegatingJobXMLLoaderServiceImpl.java

/*
 * Copyright 2012 International Business Machines Corp.
 * 
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership. Licensed 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 com.ibm.jbatch.container.services.impl;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.ibm.jbatch.container.exception.BatchContainerRuntimeException;
import com.ibm.jbatch.container.exception.BatchContainerServiceException;
import com.ibm.jbatch.container.servicesmanager.ServicesManagerImpl;
import com.ibm.jbatch.spi.services.IBatchConfig;
import com.ibm.jbatch.spi.services.IJobXMLLoaderService;

public class DelegatingJobXMLLoaderServiceImpl implements IJobXMLLoaderService {

    
    private final static Logger logger = Logger.getLogger(DelegatingBatchArtifactFactoryImpl.class.getName());
    private final static String CLASSNAME = DelegatingBatchArtifactFactoryImpl.class.getName();
    
    protected static IJobXMLLoaderService preferredJobXmlLoader = ServicesManagerImpl.getInstance().getPreferredJobXMLLoaderService();
    
    public static final String PREFIX = "META-INF/batch-jobs/";
    
    
    @Override
	public String loadJSL(String id) {
	    
        String method = "loadJob";
        
        logger.entering(CLASSNAME, method);
        
        String jobXML = null;

        if (!preferredJobXmlLoader.getClass().equals(this.getClass())) {
            jobXML = preferredJobXmlLoader.loadJSL(id);
        } else {
            if (logger.isLoggable(Level.FINER)) {
                logger.log(Level.FINER, "No preferred job xml loader is detected in configuration");
            } 
        }

        if (jobXML != null) {
            if (logger.isLoggable(Level.FINER)) {
                logger.log(Level.FINER, "Preferred job xml loader loaded job with id " + id +".");
            } 
            return jobXML;
        }
        
        if (logger.isLoggable(Level.FINER)) {
            logger.log(Level.FINER, "Preferred job xml loader failed to load " + id +". Defaulting to " + PREFIX);
        }
        
	    jobXML =  loadJobFromBatchJobs(id);
	    
	    if (jobXML == null) {
	        
	        if (logger.isLoggable(Level.FINER)) {
	            logger.log(Level.FINER, "Failed to load " + id +" from " + PREFIX);
	        }
	        
	        throw new BatchContainerServiceException("Could not load job xml with id: " + id);
	    }
	    
        if (logger.isLoggable(Level.FINER)) {
            logger.log(Level.FINER, "Loaded job xml with " + id +" from " + PREFIX);
        }
	    
	    return jobXML;
	    
	}


	private static String loadJobFromBatchJobs(String id) {

	    ClassLoader tccl = Thread.currentThread().getContextClassLoader();
	    
	    String relativePath = PREFIX + id + ".xml";
	    
	    InputStream stream = tccl.getResourceAsStream(relativePath);
	    
	   if (stream == null) {
           throw new BatchContainerRuntimeException(new FileNotFoundException(
                   "Cannot find an XML file under " + PREFIX + " with the following name " + id + ".xml"));
       }

	    return readJobXML(stream);
	    
    }


	private static String readJobXML(InputStream stream)  {
		
		StringBuffer out = new StringBuffer();
		
		try {
	        byte[] b = new byte[4096];
	        for (int i; (i = stream.read(b)) != -1;) {
	            out.append(new String(b, 0, i));
	        }
		} catch (FileNotFoundException e) {
			throw new BatchContainerServiceException(e);
        } catch (IOException e) {
            throw new BatchContainerServiceException(e);
        } 
		
        return out.toString();
	}


    @Override
    public void init(IBatchConfig batchConfig) throws BatchContainerServiceException {
        // TODO Auto-generated method stub
        
    }


    @Override
    public void shutdown() throws BatchContainerServiceException {
        // TODO Auto-generated method stub
        
    }
	
}