org.duracloud.snapshot.service.impl.DpnManifestReader Maven / Gradle / Ivy

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/*
 * The contents of this file are subject to the license and copyright
 * detailed in the LICENSE and NOTICE files at the root of the source
 * tree and available online at
 *
 *     http://duracloud.org/license/
 */
package org.duracloud.snapshot.service.impl;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;

import org.springframework.batch.core.StepExecution;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.NonTransientResourceException;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputException;

/**
 * This class reads a DPN manifest 
 * @author Daniel Bernstein
 *         Date: Jul 28, 2015
 */
public class DpnManifestReader extends StepExecutionSupport implements ItemReader {

    private File manifestFile;
    private BufferedReader reader;

    /**
     * @param manifestFile an md5 manifest file.
     */
     public DpnManifestReader(File manifestFile) {
         this.manifestFile = manifestFile;
    }

    /* (non-Javadoc)
     * @see org.springframework.batch.item.ItemReader#read()
     */
    @Override
    public synchronized ManifestEntry read()
        throws Exception,
            UnexpectedInputException,
            ParseException,
            NonTransientResourceException {
        if(this.reader == null){
            this.reader = new BufferedReader(new FileReader(manifestFile));
            long linesRead = getItemsRead();
            
            if(linesRead > 0){
                for(long i = 0; i < linesRead; i++){
                    this.reader.readLine();
                }
            }
        }
        
        String line = this.reader.readLine();
        if(line != null){
            return ManifestFileHelper.parseManifestEntry(line);
        }else{
            return null;
        }
        
    }

    /* (non-Javadoc)
     * @see org.springframework.batch.core.StepExecutionListener#beforeStep(org.springframework.batch.core.StepExecution)
     */
    @Override
    public void beforeStep(StepExecution stepExecution) {
        super.beforeStep(stepExecution);
    }

}