Package org.marc4j

Source Code of org.marc4j.MarcDirStreamReader

// $Id: MarcDirStreamReader.java,v 1.2 2008/10/17 06:47:06 haschart Exp $
/**
* Copyright (C) 2004 Bas Peters
*
* This file is part of MARC4J
*
* MARC4J 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 2.1 of the License, or (at your option) any later version.
*
* MARC4J 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 MARC4J; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*
*/

package org.marc4j;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;

import org.marc4j.MarcPermissiveStreamReader;
import org.marc4j.MarcReader;
import org.marc4j.marc.Record;

/**
* <p>
* A Marc reader which instead of handling a single file of MARC records
* it handles a directory, which it will scan for all .mrc files, and
* iterate through all of them in turn.
* </p>
* @author Robert Haschart
* @version $Revision: 1.2 $
*/

public class MarcDirStreamReader implements MarcReader
{
    File list[];
    MarcReader curFileReader;
    int curFileNum;
    boolean permissive;
    boolean convertToUTF8;
    String defaultEncoding;
   
    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     *
     * @param dirName - The path of the directory from which to read all of the .mrc files
     */    
    public MarcDirStreamReader(String dirName)
    {
        File dir = new File(dirName);
        init(dir, false, false, null);
    }
   
    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     *
     * @param dir - The path of the directory from which to read all of the .mrc files
     */    
    public MarcDirStreamReader(File dir)
    {
        init(dir, false, false, null);
    }

    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     * Takes the values passed in for permissive and convertToUTF8 and passes them on
     * to each of the MarcPermissiveStreamReader that it creates.
     *
     * @param dirName - The path of the directory from which to read all of the .mrc files
     * @param permissive - Set to true to specify that reader should try to handle and recover
     *                     from errors in the input.
     * @param convertToUTF8 - Set to true to specify that reader should convert the records
     *               being read to UTF-8 encoding as they are being read.
     */    
    public MarcDirStreamReader(String dirName, boolean permissive, boolean convertToUTF8)
    {
        File dir = new File(dirName);
        init(dir, permissive, convertToUTF8, null);
    }
   
    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     * Takes the values passed in for permissive and convertToUTF8 and passes them on
     * to each of the MarcPermissiveStreamReader that it creates.
     *
     * @param dir - The path of the directory from which to read all of the .mrc files
     * @param permissive - Set to true to specify that reader should try to handle and recover
     *                     from errors in the input.
     * @param convertToUTF8 - Set to true to specify that reader should convert the records
     *               being read to UTF-8 encoding as they are being read.
     */    
    public MarcDirStreamReader(File dir, boolean permissive, boolean convertToUTF8)
    {
        init(dir, permissive, convertToUTF8, null);
    }

    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     * Takes the values passed in for permissive and convertToUTF8 and passes them on
     * to each of the MarcPermissiveStreamReader that it creates.
     *
     * @param dirName - The path of the directory from which to read all of the .mrc files
     * @param permissive - Set to true to specify that reader should try to handle and recover
     *                     from errors in the input.
     * @param convertToUTF8 - Set to true to specify that reader should convert the records
     *               being read to UTF-8 encoding as they are being read.
     * @param defaultEncoding - Specifies the character encoding that the records being read
     *               are presumed to be in..
     */    
    public MarcDirStreamReader(String dirName, boolean permissive, boolean convertToUTF8, String defaultEncoding)
    {
        File dir = new File(dirName);
        init(dir, permissive, convertToUTF8, defaultEncoding);
    }
   
    /**
     * Constructs an instance that traverses the directory specified in the parameter.
     * Takes the values passed in for permissive and convertToUTF8 and passes them on
     * to each of the MarcPermissiveStreamReader that it creates.
     *
     * @param dir - The path of the directory from which to read all of the .mrc files
     * @param permissive - Set to true to specify that reader should try to handle and recover
     *                     from errors in the input.
     * @param convertToUTF8 - Set to true to specify that reader should convert the records
     *               being read to UTF-8 encoding as they are being read.
     * @param defaultEncoding - Specifies the character encoding that the records being read
     *               are presumed to be in..
     */    
    public MarcDirStreamReader(File dir, boolean permissive, boolean convertToUTF8, String defaultEncoding)
    {
        init(dir, permissive, convertToUTF8, defaultEncoding);
    }

    private void init(File dir, boolean permissive, boolean convertToUTF8, String defaultEncoding)
    {
        FilenameFilter filter = new FilenameFilter()
        {
            public boolean accept(File dir, String name)
            {
                return(name.endsWith("mrc"));
            }
        };
        this.permissive = permissive;
        this.convertToUTF8 = convertToUTF8;
        list = dir.listFiles(filter);
        java.util.Arrays.sort(list);
        curFileNum = 0;
        curFileReader = null;
        this.defaultEncoding = defaultEncoding;
    }
   
    /**
     * Returns true if the iteration has more records, false otherwise.
     */
    public boolean hasNext()
    {
        if (curFileReader == null || curFileReader.hasNext() == false)
        {
            nextFile();
        }
        return (curFileReader == null ? false : curFileReader.hasNext());
    }

    private void nextFile()
    {
        if (curFileNum != list.length)
        {
            try
            {
                System.err.println("Switching to input file: "+ list[curFileNum]);
                if (defaultEncoding != null)
                {
                    curFileReader = new MarcPermissiveStreamReader(new FileInputStream(list[curFileNum++]), permissive, convertToUTF8, defaultEncoding);
                }
                else
                {
                    curFileReader = new MarcPermissiveStreamReader(new FileInputStream(list[curFileNum++]), permissive, convertToUTF8);
                }
            }
            catch (FileNotFoundException e)
            {
                nextFile();
            }
        }
        else
        {
            curFileReader = null;
        }
    }

    /**
     * Returns the next record in the iteration.
     *
     * @return Record - the record object
     */
    public Record next()
    {
        if (curFileReader == null || curFileReader.hasNext() == false)
        {
            nextFile();
        }
        return (curFileReader == null ? null : curFileReader.next());
    }

}
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