fr.calamus.common.tools.AbstractTxtFileAccess.java Source code

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Here is the source code for fr.calamus.common.tools.AbstractTxtFileAccess.java

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package fr.calamus.common.tools;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
//import org.apache.commons.logging.Log;
//import org.apache.commons.logging.LogFactory;

/**
 * Reads/write lines in a text file
 * @author haerwynn
 */
public abstract class AbstractTxtFileAccess {

    //private static final Log log = LogFactory.getLog(AbstractTxtFileAccess.class);
    protected static final String CHARSET = "ISO-8859-15";
    protected String charset;

    public AbstractTxtFileAccess(String charset) {
        if (charset != null)
            this.charset = charset;
        else
            this.charset = CHARSET;

    }

    /**
     *
     * @return the file
     */
    protected abstract File getFile();

    /**
     * Prepares the file for writing; if the file exists, deletes it before.
     * @return
     * @throws IOException
     */
    protected BufferedWriter prepareBufferedWriter() throws IOException {
        File f = getFile();
        if (!f.getParentFile().exists())
            f.getParentFile().mkdirs();
        if (f.exists()) {
            f.delete();
            //log.debug("prepareBufferedWriter : " + f.getAbsolutePath() + " deleted");
        }
        f.createNewFile();
        //log.debug("prepareBufferedWriter : " + f.getAbsolutePath() + " created");
        BufferedWriter bw = new BufferedWriter(
                new OutputStreamWriter(new FileOutputStream(f), Charset.forName(charset)));
        return bw;
    }

    /**
     * Saves data (obtained by getLines()) in the file.
     */
    public void save() {
        try {
            BufferedWriter bw = prepareBufferedWriter();
            List<String> lines = getLines();
            for (int i = 0; i < lines.size(); i++) {
                bw.write(lines.get(i));
                bw.newLine();
            }
            bw.flush();
            bw.close();
        } catch (IOException ex) {
            //log.error("", ex);
            ex.printStackTrace();
        }
    }

    /**
     * Loads data from file then sends it in processData().
     */
    public void load() {
        File f = getFile();
        if (!f.exists()) {
            return;
        }
        try {
            BufferedReader br = new BufferedReader(
                    new InputStreamReader(new FileInputStream(f), Charset.forName(charset)));
            String l;
            int i = 0;
            List<String> lines = new ArrayList<>();
            while ((l = br.readLine()) != null) {
                i++;
                //log.debug("reading line "+i+" : "+l);
                if (!l.startsWith("#"))
                    lines.add(l);
            }
            br.close();
            processData(lines);
        } catch (IOException ex) {
            //log.error("", ex);
            ex.printStackTrace();
        }

    }

    /**
     *
     * @return data to write in the file
     */
    protected abstract List<String> getLines();

    /**
     * Processes the data
     * @param lines data read in the file
     */
    protected abstract void processData(List<String> lines);

}