Example usage for java.io LineNumberReader LineNumberReader

Introduction

In this page you can find the example usage for java.io LineNumberReader LineNumberReader.

Prototype

public LineNumberReader(Reader in, int sz) 

Source Link

Document

Create a new line-numbering reader, reading characters into a buffer of the given size.

Usage

From source file:Main.java

public static void main(String[] args) throws IOException {
    int i;//from   ww  w.j a v  a2 s .  co m
    // create new reader
    FileReader fr = new FileReader("C:/test.txt");
    LineNumberReader lnr = new LineNumberReader(fr, 200);

    // read till the end of the stream
    while ((i = lnr.read()) != -1) {
        // skip one byte
        lnr.skip(1);

        // converts integer to char
        char c = (char) i;

        // prints char
        System.out.print(c);
    }
    lnr.close();
}

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From source file:org.opencms.util.CmsRfsFileViewer.java

/**
 * Return the view portion of lines of text from the underlying file or an 
 * empty String if <code>{@link #isEnabled()}</code> returns <code>false</code>.<p>
 * /*from   w  ww  .  j  a  v a2  s .c o m*/
 * @return the view portion of lines of text from the underlying file or an 
 *         empty String if <code>{@link #isEnabled()}</code> returns <code>false</code>
 * @throws CmsRfsException if something goes wrong
 */
public String readFilePortion() throws CmsRfsException {

    if (m_enabled) {
        // if we want to view the log file we have to set the internal m_windowPos to the last window 
        // to view the end: 
        int lines = -1;
        int startLine;
        if (m_isLogfile) {
            lines = scrollToFileEnd();
            // for logfile mode we show the last window of window size: 
            // it could be possible that only 4 lines are in the last window 
            // (e.g.: 123 lines with windowsize 10 -> last window has 3 lines) 
            // so we ignore the window semantics and show the n last lines: 
            startLine = lines - m_windowSize;
        } else {
            m_windowPos = 0;
            startLine = m_windowPos * m_windowSize;
        }
        LineNumberReader reader = null;
        try {
            // don't make the buffer too big, just big enough for windowSize lines (estimation: avg. of 200 characters per line) 
            // to save reading too much (this optimizes to read the first windows, much later windows will be slower...)
            reader = new LineNumberReader(
                    new BufferedReader(new InputStreamReader(new FileInputStream(m_filePath), m_fileEncoding)),
                    m_windowSize * 200);
            int currentLine = 0;
            // skip the lines to the current window:
            while (startLine > currentLine) {
                reader.readLine();
                currentLine++;
            }
            StringBuffer result = new StringBuffer();
            String read = reader.readLine();

            // logfile treatment is different
            // we invert the lines: latest come first
            if (m_isLogfile) {
                // stack is java hall of shame member... but standard
                Stack inverter = new Stack();
                for (int i = m_windowSize; (i > 0) && (read != null); i--) {
                    inverter.push(read);
                    read = reader.readLine();
                }
                // pop-off:
                while (!inverter.isEmpty()) {
                    result.append(inverter.pop());
                    result.append('\n');
                }
            } else {
                for (int i = m_windowSize; (i > 0) && (read != null); i--) {
                    result.append(read);
                    result.append('\n');
                    read = reader.readLine();
                }
            }
            return CmsEncoder.escapeXml(result.toString());
        } catch (IOException ioex) {
            CmsRfsException ex = new CmsRfsException(
                    Messages.get().container(Messages.ERR_FILE_ARG_ACCESS_1, m_filePath), ioex);
            throw ex;
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    LOG.error(e.getLocalizedMessage(), e);
                }
            }
        }
    } else {
        return Messages.get().getBundle().key(Messages.GUI_FILE_VIEW_NO_PREVIEW_0);
    }
}

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