Example usage for java.io RandomAccessFile seek

Introduction

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

Prototype

public void seek(long pos) throws IOException 

Source Link

Document

Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.

Usage

From source file:com.sun.faban.harness.webclient.ResultAction.java

private String editResultInfo(String runID) throws FileNotFoundException, IOException {
    RunId runId = new RunId(runID);
    String ts = null;// w w w  . j av a2 s . c o  m
    String[] status = new String[2];
    File file = new File(Config.OUT_DIR + runID + '/' + Config.RESULT_INFO);
    RandomAccessFile rf = new RandomAccessFile(file, "rwd");
    long size = rf.length();
    byte[] buffer = new byte[(int) size];
    rf.readFully(buffer);
    String content = new String(buffer, 0, (int) size);
    int idx = content.indexOf('\t');
    if (idx != -1) {
        status[0] = content.substring(0, idx).trim();
        status[1] = content.substring(++idx).trim();
    } else {
        status[0] = content.trim();
        int lastIdxln = status[0].lastIndexOf("\n");
        if (lastIdxln != -1)
            status[0] = status[0].substring(0, lastIdxln - 1);
    }
    if (status[1] != null) {
        ts = status[1];
    } else {
        String paramFileName = runId.getResultDir().getAbsolutePath() + File.separator + "run.xml";
        File paramFile = new File(paramFileName);
        long dt = paramFile.lastModified();
        ts = dateFormat.format(new Date(dt));
        rf.seek(rf.length());
        rf.writeBytes('\t' + ts.trim());
    }
    rf.close();
    return ts;
}

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From source file:com.lewa.crazychapter11.MainActivity.java

private void WriteToSdCard(String content) {
    try {/*  w ww .jav a 2  s.  c  o m*/
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            File sdCardDir = Environment.getExternalStorageDirectory();
            File targetFile = new File(sdCardDir.getCanonicalPath() + FILE_NAME_SDCARD);

            Log.i("crazyFile", "WriteToSdCard: sdCardDir=" + sdCardDir + " \n targetFile=" + targetFile);
            RandomAccessFile raf = new RandomAccessFile(targetFile, "rw");
            raf.seek(targetFile.length());
            raf.write(content.getBytes());
            raf.close();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

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From source file:org.kuali.student.git.model.SvnRevisionMapper.java

private long createRevisionEntry(RandomAccessFile dataFile, long endOfDataFileOffset, long revision,
        List<String> revisionLines) throws IOException {

    OutputStream revisionMappingStream = null;

    ByteArrayOutputStream bytesOut;

    revisionMappingStream = new BZip2CompressorOutputStream(bytesOut = new ByteArrayOutputStream());

    PrintWriter pw = new PrintWriter(revisionMappingStream);

    IOUtils.writeLines(revisionLines, "\n", pw);

    pw.flush();//from  w  w w . j  a  v a 2 s.  c  o  m

    pw.close();

    byte[] data = bytesOut.toByteArray();

    dataFile.seek(endOfDataFileOffset);

    dataFile.write(data);

    return data.length;
}

---

From source file:org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl.java

static private void truncateBlock(File blockFile, File metaFile, long oldlen, long newlen) throws IOException {
    LOG.info("truncateBlock: blockFile=" + blockFile + ", metaFile=" + metaFile + ", oldlen=" + oldlen
            + ", newlen=" + newlen);

    if (newlen == oldlen) {
        return;/*from  w ww  .j  a va  2s .  c  o  m*/
    }
    if (newlen > oldlen) {
        throw new IOException(
                "Cannot truncate block to from oldlen (=" + oldlen + ") to newlen (=" + newlen + ")");
    }

    DataChecksum dcs = BlockMetadataHeader.readHeader(metaFile).getChecksum();
    int checksumsize = dcs.getChecksumSize();
    int bpc = dcs.getBytesPerChecksum();
    long n = (newlen - 1) / bpc + 1;
    long newmetalen = BlockMetadataHeader.getHeaderSize() + n * checksumsize;
    long lastchunkoffset = (n - 1) * bpc;
    int lastchunksize = (int) (newlen - lastchunkoffset);
    byte[] b = new byte[Math.max(lastchunksize, checksumsize)];

    RandomAccessFile blockRAF = new RandomAccessFile(blockFile, "rw");
    try {
        //truncate blockFile 
        blockRAF.setLength(newlen);

        //read last chunk
        blockRAF.seek(lastchunkoffset);
        blockRAF.readFully(b, 0, lastchunksize);
    } finally {
        blockRAF.close();
    }

    //compute checksum
    dcs.update(b, 0, lastchunksize);
    dcs.writeValue(b, 0, false);

    //update metaFile 
    RandomAccessFile metaRAF = new RandomAccessFile(metaFile, "rw");
    try {
        metaRAF.setLength(newmetalen);
        metaRAF.seek(newmetalen - checksumsize);
        metaRAF.write(b, 0, checksumsize);
    } finally {
        metaRAF.close();
    }
}

---

From source file:com.example.android.vault.EncryptedDocument.java

/**
 * Encrypt and write the given stream as a full section. Writes section
 * header and encrypted data starting at the current file offset. When
 * finished, file offset is at the end of the entire section.
 *///from  w ww  .j  av  a 2 s.c om
private int writeSection(RandomAccessFile f, InputStream in) throws IOException, GeneralSecurityException {
    final long start = f.getFilePointer();

    // Write header; we'll come back later to finalize details
    final Section section = new Section();
    section.write(f);

    final long dataStart = f.getFilePointer();

    mRandom.nextBytes(section.iv);

    final IvParameterSpec ivSpec = new IvParameterSpec(section.iv);
    mCipher.init(Cipher.ENCRYPT_MODE, mDataKey, ivSpec);
    mMac.init(mMacKey);

    int plainLength = 0;
    byte[] inbuf = new byte[8192];
    byte[] outbuf;
    int n;
    while ((n = in.read(inbuf)) != -1) {
        plainLength += n;
        outbuf = mCipher.update(inbuf, 0, n);
        if (outbuf != null) {
            mMac.update(outbuf);
            f.write(outbuf);
        }
    }

    outbuf = mCipher.doFinal();
    if (outbuf != null) {
        mMac.update(outbuf);
        f.write(outbuf);
    }

    section.setMac(mMac.doFinal());

    final long dataEnd = f.getFilePointer();
    section.length = dataEnd - dataStart;

    // Rewind and update header
    f.seek(start);
    section.write(f);
    f.seek(dataEnd);

    return plainLength;
}

---

From source file:gate.util.reporting.DocTimeReporter.java

/**
 * A method for reading the file upside down.
 *
 * @param fileToBeRead//from  www .j  a va2  s . c om
 *          An object of the file to be read.
 * @param chunkSize
 *          An integer specifying the size of the chunks in which file will be
 *          read.
 * @return A long value pointing to the start position of the given file
 *         chunk.
 */
private long tail(File fileToBeRead, int chunkSize) throws BenchmarkReportInputFileFormatException {
    RandomAccessFile raf = null;
    try {
        raf = new RandomAccessFile(fileToBeRead, "r");
        Vector<String> lastNlines = new Vector<String>();
        int delta = 0;
        long curPos = 0;
        curPos = raf.length() - 1;
        long fromPos;
        byte[] bytearray;
        while (true) {
            fromPos = curPos - chunkSize;
            if (fromPos <= 0) {
                raf.seek(0);
                bytearray = new byte[(int) curPos];
                raf.readFully(bytearray);
                if (parseLinesFromLast(bytearray, lastNlines, fromPos)) {
                    if (fromPos < 0)
                        fromPos = 0;
                }
                break;
            } else {
                raf.seek(fromPos);
                bytearray = new byte[chunkSize];
                raf.readFully(bytearray);
                if (parseLinesFromLast(bytearray, lastNlines, fromPos)) {
                    break;
                }
                delta = lastNlines.get(lastNlines.size() - 1).length();
                lastNlines.remove(lastNlines.size() - 1);
                curPos = fromPos + delta;
            }
        }
        if (fromPos < 0)
            throw new BenchmarkReportInputFileFormatException(
                    getBenchmarkFile() + " does not contain a marker named " + getLogicalStart()
                            + " indicating logical start of a run.");
        return fromPos;

    } catch (IOException e) {
        e.printStackTrace();
        return -1;
    } finally {
        IOUtils.closeQuietly(raf);
    }
}

---

From source file:org.commoncrawl.service.crawler.CrawlLog.java

/**
 * seek out next instance of sync bytes in the file input stream
 * //  w w w.  ja va 2s  . c o  m
 * @param file
 * @throws IOException
 */
private static boolean seekToNextSyncBytesPos(byte[] syncBytesBuffer, RandomAccessFile file, long maxFileSize)
        throws IOException {

    while (file.getFilePointer() < maxFileSize) {
        try {
            // read in a sync.length buffer amount
            file.read(syncBytesBuffer);

            int syncLen = SYNC_BYTES_SIZE;

            // start scan for next sync position ...
            for (int i = 0; file.getFilePointer() < maxFileSize; i++) {
                int j = 0;
                for (; j < syncLen; j++) {
                    if (_sync[j] != syncBytesBuffer[(i + j) % syncLen])
                        break;
                }
                if (j == syncLen) {
                    // found matching sync bytes - reset file pos to before sync bytes
                    file.seek(file.getFilePointer() - SYNC_BYTES_SIZE); // position
                    // before
                    // sync
                    return true;
                }
                syncBytesBuffer[i % syncLen] = file.readByte();
            }
        } catch (IOException e) {
            LOG.warn("IOException at:" + file.getFilePointer() + " Exception:"
                    + CCStringUtils.stringifyException(e));
            LOG.warn("Skipping to:" + file.getFilePointer() + 4096);
            file.seek(file.getFilePointer() + 4096);
        }
    }
    return false;
}

---

From source file:org.commoncrawl.service.crawler.CrawlList.java

private static long readLogFileHeader(RandomAccessFile file, LogFileHeader header) throws IOException {

    file.seek(0);

    header.readHeader(file);/* www  .  ja v a2s.  c o  m*/

    return file.getFilePointer();
}

---

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

/**
 * Read new lines.//from ww  w . j  a  va 2s  .c  o m
 *
 * @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;
}

---

From source file:gate.util.reporting.DocTimeReporter.java

/**
 * Provides the functionality to separate out pipeline specific benchmark
 * entries in separate temporary benchmark files in a temporary folder in the
 * current working directory.//from w  w  w  .  j a v  a 2  s.c  om
 *
 * @param benchmarkFile
 *          An object of type File representing the input benchmark file.
 * @param report
 *          A file handle to the report file to be written.
 * @throws BenchmarkReportFileAccessException
 *           if any error occurs while accessing the input benchmark file or
 *           while splitting it.
 * @throws BenchmarkReportExecutionException
 *           if the given input benchmark file is modified while generating
 *           the report.
 */
private void splitBenchmarkFile(File benchmarkFile, File report)
        throws BenchmarkReportFileAccessException, BenchmarkReportInputFileFormatException {
    File dir = temporaryDirectory;
    // Folder already exists; then delete all files in the temporary folder
    if (dir.isDirectory()) {
        File files[] = dir.listFiles();
        for (int count = 0; count < files.length; count++) {
            if (!files[count].delete()) {
                throw new BenchmarkReportFileAccessException(
                        "Could not delete files in the folder \"" + temporaryDirectory + "\"");
            }
        }
    } else if (!dir.mkdir()) {
        throw new BenchmarkReportFileAccessException(
                "Could not create  temporary folder \"" + temporaryDirectory + "\"");
    }

    // delete report2 from the filesystem
    if (getPrintMedia().equalsIgnoreCase(MEDIA_TEXT)) {
        deleteFile(new File(report.getAbsolutePath() + ".txt"));
    } else if (getPrintMedia().equalsIgnoreCase(MEDIA_HTML)) {
        deleteFile(new File(report.getAbsolutePath() + ".html"));
    }

    RandomAccessFile in = null;
    BufferedWriter out = null;
    try {
        String logEntry = "";
        long fromPos = 0;

        // File benchmarkFileName;
        if (getLogicalStart() != null) {
            fromPos = tail(benchmarkFile, FILE_CHUNK_SIZE);
        }
        in = new RandomAccessFile(benchmarkFile, "r");

        if (getLogicalStart() != null) {
            in.seek(fromPos);
        }
        ArrayList<String> startTokens = new ArrayList<String>();
        String lastStart = "";
        Pattern pattern = Pattern.compile("(\\d+) (\\d+) (.*) (.*) \\{(.*)\\}");
        Matcher matcher = null;
        File benchmarkFileName = null;
        while ((logEntry = in.readLine()) != null) {
            matcher = pattern.matcher(logEntry);
            String startToken = "";
            if (logEntry.matches(".*START.*")) {
                String[] splittedStartEntry = logEntry.split("\\s");
                if (splittedStartEntry.length > 2) {
                    startToken = splittedStartEntry[2];
                } else {
                    throw new BenchmarkReportInputFileFormatException(getBenchmarkFile() + " is invalid.");
                }

                if (startToken.endsWith("Start")) {
                    continue;
                }
                if (!startTokens.contains(startToken)) {
                    // create a new file for the new pipeline
                    startTokens.add(startToken);
                    benchmarkFileName = new File(temporaryDirectory, startToken + "_benchmark.txt");
                    if (!benchmarkFileName.createNewFile()) {
                        throw new BenchmarkReportFileAccessException("Could not create \"" + startToken
                                + "_benchmark.txt" + "\" in directory named \"" + temporaryDirectory + "\"");
                    }
                    out = new BufferedWriter(new FileWriter(benchmarkFileName));
                    out.write(logEntry);
                    out.newLine();
                }
            }
            // if a valid benchmark entry then write it to the pipeline specific
            // file
            if (matcher != null && matcher.matches() && (validateLogEntry(matcher.group(3), startTokens)
                    || logEntry.matches(".*documentLoaded.*"))) {
                startToken = matcher.group(3).split("\\.")[0];
                if (!(lastStart.equals(startToken))) {
                    if (out != null) {
                        out.close();
                    }
                    benchmarkFileName = new File(temporaryDirectory, startToken + "_benchmark.txt");
                    out = new BufferedWriter(new FileWriter(benchmarkFileName, true));
                }
                if (out != null) {
                    out.write(logEntry);
                    out.newLine();
                }
                lastStart = startToken;
            }
        }

    } catch (IOException e) {
        e.printStackTrace();

    } finally {
        try {
            if (in != null) {
                in.close();
            }
            if (out != null) {
                out.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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