Example usage for java.io RandomAccessFile read

Introduction

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

Prototype

public int read() throws IOException 

Source Link

Document

Reads a byte of data from this file.

Usage

From source file:com.haulmont.cuba.core.sys.LogControlImpl.java

protected void skipFirstLine(RandomAccessFile logFile) throws IOException {
    boolean eol = false;
    while (!eol) {
        switch (logFile.read()) {
        case -1://from w ww  . jav a2  s . c o  m
        case '\n':
            eol = true;
            break;
        case '\r':
            eol = true;
            long cur = logFile.getFilePointer();
            if ((logFile.read()) != '\n') {
                logFile.seek(cur);
            }
            break;
        default:
            break;
        }
    }
}

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From source file:com.haulmont.cuba.core.sys.LogControlImpl.java

protected String readUtf8Line(RandomAccessFile logFile) throws IOException {
    int c = -1;//from w w  w . j a v  a  2 s. c  o  m
    boolean eol = false;
    ByteArrayOutputStream input = new ByteArrayOutputStream();

    while (!eol) {
        switch (c = logFile.read()) {
        case -1:
        case '\n':
            eol = true;
            break;
        case '\r':
            eol = true;
            long cur = logFile.getFilePointer();
            if ((logFile.read()) != '\n') {
                logFile.seek(cur);
            }
            break;
        default:
            input.write((byte) c);
            break;
        }
    }
    if ((c == -1) && (input.size() == 0)) {
        return null;
    }

    return new String(input.toByteArray(), StandardCharsets.UTF_8);
}

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From source file:org.apache.hadoop.hdfs.server.namenode.TestFSEditLogLoader.java

/**
 * Corrupt the byte at the given offset in the given file,
 * by subtracting 1 from it.//from  w  ww  .  ja  v  a  2 s.  co m
 */
private void corruptByteInFile(File file, long offset) throws IOException {
    RandomAccessFile raf = new RandomAccessFile(file, "rw");
    try {
        raf.seek(offset);
        int origByte = raf.read();
        raf.seek(offset);
        raf.writeByte(origByte - 1);
    } finally {
        IOUtils.closeStream(raf);
    }
}

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From source file:com.dotmarketing.servlets.taillog.Tailer.java

/**
 * Version of readline() that returns null on EOF rather than a partial line.
 * @param reader the input file//w  w w  .j  ava2s .  co m
 * @return the line, or null if EOF reached before '\n' is seen.
 * @throws IOException if an error occurs.
 */
private String readLine(RandomAccessFile reader) throws IOException {
    StringBuffer sb = new StringBuffer();
    int ch;
    boolean seenCR = false;
    while ((ch = reader.read()) != -1) {
        switch (ch) {
        case '\n':
            return sb.toString();
        case '\r':
            seenCR = true;
            break;
        default:
            if (seenCR) {
                sb.append('\r');
                seenCR = false;
            }
            sb.append((char) ch); // add character, not its ascii value
        }
    }
    return null;
}

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From source file:info.ajaxplorer.client.http.AjxpFileBody.java

public void writeTo(OutputStream out) {
    InputStream in;//from w w w .  j a v  a 2s .  c  o m
    try {
        if (this.chunkSize > 0) {
            //System.out.println("Uploading file part " + this.chunkIndex);
            RandomAccessFile raf = new RandomAccessFile(getFile(), "r");
            int start = chunkIndex * this.chunkSize;
            int count = 0;
            int limit = chunkSize;
            if (chunkIndex == (totalChunks - 1)) {
                limit = lastChunkSize;
            }
            raf.seek(start);
            while (count < limit) {
                int byt = raf.read();
                out.write(byt);
                count++;
            }
            raf.close();
            //System.out.println("Sent " + count);            
        } else {
            in = new FileInputStream(getFile());
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
            in.close();
        }
        this.chunkIndex++;
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

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From source file:hoot.services.info.ErrorLog.java

public String getErrorlog(long maxLength) throws Exception {

    File file = new File(_errLogPath);
    RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r");
    int lines = 0;
    StringBuilder builder = new StringBuilder();
    long length = file.length();
    //length--;//w w  w. jav a  2  s  . co  m

    long startOffset = 0;
    if (length > maxLength) {
        startOffset = length - maxLength;
    }
    for (long seek = startOffset; seek < length; seek++) {
        randomAccessFile.seek(seek);
        char c = (char) randomAccessFile.read();
        builder.append(c);
    }

    randomAccessFile.close();

    return builder.toString();
}

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From source file:org.mitre.mpf.mvc.util.tailer.MpfLogTailer.java

/**
 * Read new lines.//from  ww w .ja v  a 2s  . c om
 *
 * @param reader The file to read
 * @param maxLines The maximum number of lines to read
 * @return The number of lines read
 * @throws IOException if an I/O error occurs.
 */
private int readLines(RandomAccessFile reader, int maxLines) throws IOException {
    int numLines = 0;
    StringBuilder sb = new StringBuilder();

    long pos = reader.getFilePointer();
    long rePos = pos; // position to re-read

    byte ch;
    boolean seenCR = false;
    while (((ch = (byte) (reader.read())) != -1) && (numLines < maxLines)) {
        switch (ch) {
        case '\n':
            seenCR = false; // swallow CR before LF
            if (listener.handle(sb.toString())) {
                numLines++;
            }
            sb.setLength(0);
            rePos = pos + 1;
            break;
        case '\r':
            if (seenCR) {
                sb.append('\r');
            }
            seenCR = true;
            break;
        default:
            if (seenCR) {
                seenCR = false; // swallow final CR
                if (listener.handle(sb.toString())) {
                    numLines++;
                }
                sb.setLength(0);
                rePos = pos + 1;
            }
            sb.append((char) ch); // add character, not its ascii value
        }

        pos = reader.getFilePointer();
    }

    reader.seek(rePos); // Ensure we can re-read if necessary
    position = rePos;

    return numLines;
}

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From source file:dk.netarkivet.common.utils.FileUtils.java

/**
 * Read the last line in a file. Note this method is not UTF-8 safe.
 *
 * @param file input file to read last line from.
 * @return The last line in the file (ending newline is irrelevant),
 * returns an empty string if file is empty.
 * @throws ArgumentNotValid on null argument, or file is not a readable
 * file./* w  w  w .  j a  v a 2s.  c o  m*/
 * @throws IOFailure on IO trouble reading file.
 */
public static String readLastLine(File file) {
    ArgumentNotValid.checkNotNull(file, "File file");
    if (!file.isFile() || !file.canRead()) {
        final String errMsg = "File '" + file.getAbsolutePath() + "' is not a readable file.";
        log.warn(errMsg);
        throw new ArgumentNotValid(errMsg);
    }
    if (file.length() == 0) {
        return "";
    }
    RandomAccessFile rafile = null;
    try {
        rafile = new RandomAccessFile(file, "r");
        //seek to byte one before end of file (remember we know the file is
        // not empty) - this ensures that an ending newline is not read
        rafile.seek(rafile.length() - 2);
        //now search to the last linebreak, or beginning of file
        while (rafile.getFilePointer() != 0 && rafile.read() != '\n') {
            //search back two, because we just searched forward one to find
            //newline
            rafile.seek(rafile.getFilePointer() - 2);
        }
        return rafile.readLine();
    } catch (IOException e) {
        final String errMsg = "Unable to access file '" + file.getAbsolutePath() + "'";
        log.warn(errMsg, e);
        throw new IOFailure(errMsg, e);
    } finally {
        try {
            if (rafile != null) {
                rafile.close();
            }
        } catch (IOException e) {
            log.debug("Unable to close file '" + file.getAbsolutePath() + "' after reading", e);
        }
    }
}

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From source file:com.haulmont.cuba.core.sys.LogControlImpl.java

@Override
public String getTail(String fileName) throws LogControlException {
    // security check, supported only valid file names
    fileName = FilenameUtils.getName(fileName);

    StringBuilder sb = new StringBuilder();
    RandomAccessFile randomAccessFile = null;
    try {/*from w w w.ja  va2s. c om*/
        File logFile = new File(logDir, fileName);
        if (!logFile.exists())
            throw new LogFileNotFoundException(fileName);

        randomAccessFile = new RandomAccessFile(logFile, "r");
        long lengthFile = randomAccessFile.length();
        if (lengthFile >= LOG_TAIL_AMOUNT_BYTES) {
            randomAccessFile.seek(lengthFile - LOG_TAIL_AMOUNT_BYTES);
            skipFirstLine(randomAccessFile);
        }
        while (randomAccessFile.read() != -1) {
            randomAccessFile.seek(randomAccessFile.getFilePointer() - 1);
            String line = readUtf8Line(randomAccessFile);
            if (line != null) {
                sb.append(line).append("\n");
            }
        }
    } catch (IOException e) {
        log.error("Error reading log file", e);
        throw new LogControlException("Error reading log file: " + fileName);
    } finally {
        if (randomAccessFile != null) {
            try {
                randomAccessFile.close();
            } catch (IOException ignored) {
            }
        }
    }
    return sb.toString();
}

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From source file:org.ala.spatial.util.AnalysisJobMaxent.java

private String getMaxentError(File file, int count) {
    try {//from  w ww  .j ava2s. c  om
        RandomAccessFile rf = new RandomAccessFile(file, "r");

        // first check if maxent threw a 'No species selected' error
        String nosp = rf.readLine(); // first line: date/time
        nosp = rf.readLine(); // second line: maxent version
        nosp = rf.readLine(); // third line: "No species selected"
        if (nosp.equals("No species selected")) {
            return "No species selected";
        }

        long flen = file.length() - 1;
        int nlcnt = -1;
        StringBuilder lines = new StringBuilder();
        while (nlcnt != count) {
            rf.seek(flen--);
            char c = (char) rf.read();
            lines.append(c);
            if (c == '\n') {
                nlcnt++;
            }

        }
        String line = lines.reverse().toString();
        if (line.contains("Warning: Skipping species because it has 0 test samples")) {
            return "Warning: Skipping species because it has 0 test samples";
        }

        rf.close();
    } catch (Exception e) {
        System.out.println("Unable to read lines");
        e.printStackTrace(System.out);
    }

    // return false anyways
    return null;
}

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