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.phonegap.FileUtils.java

/**
 * Write contents of file.//from ww w  .ja v a 2 s.  co  m
 * 
 * @param filename         The name of the file.
 * @param data            The contents of the file.
 * @param offset         The position to begin writing the file.         
 * @throws FileNotFoundException, IOException
 */
public long write(String filename, String data, long offset) throws FileNotFoundException, IOException {
    RandomAccessFile file = new RandomAccessFile(filename, "rw");
    file.seek(offset);
    file.writeBytes(data);
    file.close();

    return data.length();
}

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From source file:dk.netarkivet.common.utils.cdx.BinSearch.java

/** Returns the position of a line between startpos and endpos.
 * If no line other than the one starting at startpos can be found,
 * returns -1. Also sets the file pointer to the start of the line.
 * @param in The file to read from//  w w w  . ja  va2  s .  com
 * @param startpos The lower bound for the position.  Must be the
 * start of a line.
 * @param endpos The upper bound for the position.  Must be the start of
 * a line or EOF.
 * @return The position of a line s.t. startpos < returnval < endpos,
 * or -1 if no such line can be found.
 * @throws IOException If some I/O error occurs
 */
private static long findMiddleLine(RandomAccessFile in, long startpos, long endpos) throws IOException {
    // First check that there is a middle line at all.
    // If there is a line after startpos, but before endpos,
    // we remember it and as soon as we hit that line.
    long firstmiddleline = skipToLine(in, startpos);
    if (firstmiddleline == endpos) {
        return -1;
    }
    long newmidpos = endpos;
    int div = 1;
    while (newmidpos == endpos) {
        // Drat, newmidpos is not far enough back.
        // Divide back until we find a previous line.
        div *= 2;
        // Find an earlier point, half as far from startpos as the previous
        newmidpos = startpos + (endpos - startpos) / div;
        // If we get beyond the found line after the start line, just
        // return that.
        if (newmidpos < firstmiddleline) {
            newmidpos = firstmiddleline;
            in.seek(newmidpos);
            break;
        }
        // Now find the first line after the new middle
        newmidpos = skipToLine(in, newmidpos);
    }
    // Now the midpos should be != startpos && != endpos
    assert newmidpos != startpos : "Invariant violated: Newmidpos > startpos";
    return newmidpos;
}

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From source file:fr.gael.dhus.server.ftp.DHuSFtpProduct.java

@Override
public InputStream createInputStream(long offset) throws IOException {
    File file = new File(product.getDownloadablePath());
    logger.debug("Retrieving File stream from " + file.getPath());
    /*/*  www. j  a v  a 2 s. co m*/
    return new FileInputStream(file);
    */
    // permission check
    if (!doesExist()) {
        throw new IOException("No read permission : " + file.getName());
    }

    // move to the appropriate offset and create input stream
    final RandomAccessFile raf = new RandomAccessFile(file, "r");
    try {
        raf.seek(offset);
        // The IBM jre needs to have both the stream and the random access file
        // objects closed to actually close the file
        return new RegulatedInputStream.Builder(new FileInputStream(raf.getFD()) {
            public void close() throws IOException {
                super.close();
                raf.close();
            }
        }, TrafficDirection.OUTBOUND).userName(user.getName())
                .copyStreamListener(new DownloadActionRecordListener(product.getUuid(), product.getIdentifier(),
                        vfsService.getDhusUserFromFtpUser(user)))
                .build();
    } catch (IOException e) {
        raf.close();
        throw e;
    }
}

---

From source file:com.piaoyou.util.FileUtil.java

public static String[] getLastLines(File file, int linesToReturn) throws IOException, FileNotFoundException {

    final int AVERAGE_CHARS_PER_LINE = 250;
    final int BYTES_PER_CHAR = 2;

    RandomAccessFile randomAccessFile = null;
    StringBuffer buffer = new StringBuffer(linesToReturn * AVERAGE_CHARS_PER_LINE);
    int lineTotal = 0;
    try {//from  www  .jav  a2  s.  c o m
        randomAccessFile = new RandomAccessFile(file, "r");
        long byteTotal = randomAccessFile.length();
        long byteEstimateToRead = linesToReturn * AVERAGE_CHARS_PER_LINE * BYTES_PER_CHAR;

        long offset = byteTotal - byteEstimateToRead;
        if (offset < 0) {
            offset = 0;
        }

        randomAccessFile.seek(offset);
        //log.debug("SKIP IS ::" + offset);

        String line = null;
        String lineUTF8 = null;
        while ((line = randomAccessFile.readLine()) != null) {
            lineUTF8 = new String(line.getBytes("ISO8859_1"), "UTF-8");
            lineTotal++;
            buffer.append(lineUTF8).append('\n');
        }
    } finally {
        if (randomAccessFile != null) {
            try {
                randomAccessFile.close();
            } catch (IOException ex) {
            }
        }
    }

    String[] resultLines = new String[linesToReturn];
    BufferedReader in = null;
    try {
        in = new BufferedReader(new StringReader(buffer.toString()));

        int start = lineTotal /* + 2 */ - linesToReturn; // Ex : 55 - 10 = 45 ~ offset
        if (start < 0)
            start = 0; // not start line
        for (int i = 0; i < start; i++) {
            in.readLine(); // loop until the offset. Ex: loop 0, 1 ~~ 2 lines
        }

        int i = 0;
        String line = null;
        while ((line = in.readLine()) != null) {
            resultLines[i] = line;
            i++;
        }
    } catch (IOException ie) {
        log.error("Error" + ie);
        throw ie;
    } finally {
        if (in != null) {
            try {
                in.close();
            } catch (IOException ex) {
            }
        }
    }
    return resultLines;
}

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From source file:org.kalypso.shape.shp.SHPFile.java

/**
 * returns the minimum bound rectangle of RecNo's Geometrie of the shape-file <BR>
 *///from  ww  w . j a  v a2  s  . c  o  m
public SHPEnvelope getEnvelope(final SHXRecord record) throws IOException {
    final RandomAccessFile raf = getRandomAccessFile();

    final int position = record.getOffset() * 2;
    raf.seek(position + 8);
    final ShapeType shpType = ShapeType.valueOf(DataUtils.readLEInt(raf));

    /*
     * only for PolyLines, Polygons and MultiPoints minimum bounding rectangles are defined
     */
    if (shpType == ShapeType.POLYLINE || shpType == ShapeType.POLYGON || shpType == ShapeType.MULTIPOINT
            || shpType == ShapeType.POLYLINEZ || shpType == ShapeType.POLYGONZ
            || shpType == ShapeType.MULTIPOINTZ)
        return new SHPEnvelope(raf);

    return null;
}

---

From source file:org.apache.bookkeeper.bookie.EntryLogTest.java

/**
 * Explicitely try to recover using the ledgers map index at the end of the entry log
 *///from   w w w.  j a v  a  2s. c  o  m
@Test(timeout = 60000)
public void testRecoverFromLedgersMapOnV0EntryLog() throws Exception {
    File tmpDir = createTempDir("bkTest", ".dir");
    File curDir = Bookie.getCurrentDirectory(tmpDir);
    Bookie.checkDirectoryStructure(curDir);

    int gcWaitTime = 1000;
    ServerConfiguration conf = TestBKConfiguration.newServerConfiguration();
    conf.setGcWaitTime(gcWaitTime);
    conf.setLedgerDirNames(new String[] { tmpDir.toString() });
    Bookie bookie = new Bookie(conf);

    // create some entries
    EntryLogger logger = ((InterleavedLedgerStorage) bookie.ledgerStorage).entryLogger;
    logger.addEntry(1, generateEntry(1, 1));
    logger.addEntry(3, generateEntry(3, 1));
    logger.addEntry(2, generateEntry(2, 1));
    logger.addEntry(1, generateEntry(1, 2));
    logger.rollLog();

    // Rewrite the entry log header to be on V0 format
    File f = new File(curDir, "0.log");
    RandomAccessFile raf = new RandomAccessFile(f, "rw");
    raf.seek(EntryLogger.HEADER_VERSION_POSITION);
    // Write zeros to indicate V0 + no ledgers map info
    raf.write(new byte[4 + 8]);
    raf.close();

    // now see which ledgers are in the log
    logger = new EntryLogger(conf, bookie.getLedgerDirsManager());

    try {
        logger.extractEntryLogMetadataFromIndex(0L);
        fail("Should not be possible to recover from ledgers map index");
    } catch (IOException e) {
        // Ok
    }

    // Public method should succeed by falling back to scanning the file
    EntryLogMetadata meta = logger.getEntryLogMetadata(0L);
    LOG.info("Extracted Meta From Entry Log {}", meta);
    assertEquals(60, meta.getLedgersMap().get(1L).longValue());
    assertEquals(30, meta.getLedgersMap().get(2L).longValue());
    assertEquals(30, meta.getLedgersMap().get(3L).longValue());
    assertNull(meta.getLedgersMap().get(4L));
    assertEquals(120, meta.getTotalSize());
    assertEquals(120, meta.getRemainingSize());
}

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From source file:org.apache.activemq.store.kahadb.KahaDBStoreRecoveryBrokerTest.java

@Override
@SuppressWarnings("resource")
protected BrokerService createRestartedBroker() throws Exception {

    // corrupting index
    File index = new File(kahaDbDirectoryName + "/db.data");
    RandomAccessFile raf = new RandomAccessFile(index, "rw");
    switch (failTest) {
    case FailToLoad:
        index.delete();//from w ww. j a v  a 2  s.  c o  m
        raf = new RandomAccessFile(index, "rw");
        raf.seek(index.length());
        raf.writeBytes("corrupt");
        break;
    case LoadInvalid:
        // page size 0
        raf.seek(0);
        raf.writeBytes("corrupt and cannot load metadata");
        break;
    case LoadCorrupt:
        // loadable but invalid metadata
        // location of order index low priority index for first destination...
        raf.seek(8 * 1024 + 57);
        raf.writeLong(Integer.MAX_VALUE - 10);
        break;
    case LoadOrderIndex0:
        // loadable but invalid metadata
        // location of order index default priority index size
        // so looks like there are no ids in the order index
        // picked up by setCheckForCorruptJournalFiles
        raf.seek(12 * 1024 + 21);
        raf.writeShort(0);
        raf.writeChar(0);
        raf.writeLong(-1);
        break;
    default:
    }
    raf.close();

    // starting broker
    BrokerService broker = new BrokerService();
    KahaDBStore kaha = new KahaDBStore();
    kaha.setCheckForCorruptJournalFiles(failTest == CorruptionType.LoadOrderIndex0);
    // uncomment if you want to test archiving
    //kaha.setArchiveCorruptedIndex(true);
    kaha.setDirectory(new File(kahaDbDirectoryName));
    broker.setPersistenceAdapter(kaha);
    return broker;
}

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From source file:mediathekplugin.Database.java

public ArrayList<MediathekProgramItem> getMediathekPrograms(final Program program) {
    ArrayList<MediathekProgramItem> result = new ArrayList<MediathekProgramItem>();
    String channelName = unifyChannelName(program.getChannel().getName());
    HashMap<Long, ArrayList<Integer>> programsMap = mChannelItems.get(channelName);
    // search parts in brackets like for ARD
    if (programsMap == null && channelName.contains("(")) {
        String bracketPart = StringUtils.substringBetween(channelName, "(", ")");
        programsMap = mChannelItems.get(bracketPart);
    }//  ww w. j  a  v a 2s  .c  o m
    // search for partial name, if full name is not found
    if (programsMap == null && channelName.contains(" ")) {
        String firstPart = StringUtils.substringBefore(channelName, " ");
        programsMap = mChannelItems.get(firstPart);
    }
    if (programsMap == null) {
        for (Entry<String, HashMap<Long, ArrayList<Integer>>> entry : mChannelItems.entrySet()) {
            if (StringUtils.startsWithIgnoreCase(channelName, entry.getKey())) {
                programsMap = entry.getValue();
                break;
            }
        }
    }
    if (programsMap == null) {
        return result;
    }
    String title = program.getTitle();
    ArrayList<Integer> programs = programsMap.get(getKey(title));
    if (programs == null && title.endsWith(")") && title.contains("(")) {
        String newTitle = StringUtils.substringBeforeLast(title, "(").trim();
        programs = programsMap.get(getKey(newTitle));
    }
    if (programs == null && title.endsWith("...")) {
        String newTitle = title.substring(0, title.length() - 3).trim();
        programs = programsMap.get(getKey(newTitle));
    }
    if (programs == null) {
        return result;
    }
    try {
        RandomAccessFile file = new RandomAccessFile(new File(mFileName), "r");
        for (Integer byteOffset : programs) {
            file.seek(byteOffset);
            String lineEncoded = file.readLine();
            String line = new String(lineEncoded.getBytes(), "UTF-8");
            Matcher itemMatcher = ITEM_PATTERN.matcher(line);
            if (itemMatcher.find()) {
                String itemTitle = itemMatcher.group(3).trim();
                String itemUrl = itemMatcher.group(4).trim();
                result.add(new MediathekProgramItem(itemTitle, itemUrl, null));
            }
        }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return result;
}

---

From source file:org.openengsb.connector.promreport.internal.ProcessFileStore.java

private void writeTo(File proFile, ProcessInstance pi) {
    LOGGER.debug("write process instance {} to {}", pi.getId(), proFile.getName());
    RandomAccessFile raf = null;
    try {/*  ww  w  .j av a 2 s  .c  o  m*/
        raf = new RandomAccessFile(proFile, "rw");
        long position = findLastProcess(raf);
        raf.seek(position);
        String s = marshal(pi);
        raf.writeBytes(s);
        raf.write(0x0A);
        raf.writeBytes(ENDDOC);
    } catch (Exception e) {
        throw new RuntimeException(e);
    } finally {
        try {
            raf.close();
        } catch (IOException e) {
        }
    }
}

---

From source file:de.micromata.genome.logging.spi.ifiles.IndexHeader.java

public String readSearchFromLog(Integer offset, RandomAccessFile file, String name) throws IOException {
    Integer fieldoffset = searchFieldsOffsets.get(name);
    if (fieldoffset == null) {
        return null;
    }/*from   w w w.j  av  a2s. c om*/
    file.seek(offset.intValue() + fieldoffset.intValue());
    byte[] fieldBuffer = new byte[searchFieldsLength.get(name)];
    file.readFully(fieldBuffer);
    String ret = new String(fieldBuffer);
    ret = ret.trim();
    return ret;

}

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