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.dotmarketing.servlets.taillog.Tailer.java

/**
 * Read new lines.// w ww  .j  av a 2s  . c  o m
 *
 * @param reader The file to read
 * @return The new position after the lines have been read
 * @throws java.io.IOException if an I/O error occurs.
 */
private long readLines(RandomAccessFile reader) throws IOException {
    long pos = reader.getFilePointer();
    String line = readLine(reader);
    while (line != null) {
        pos = reader.getFilePointer();
        listener.handle(line);
        line = readLine(reader);
    }
    reader.seek(pos); // Ensure we can re-read if necessary
    return pos;
}

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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 {/* ww w.jav a  2s .  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:com.example.android.vault.EncryptedDocument.java

/**
 * Encrypt and write both the metadata and content sections of this
 * document, reading the content from the given pipe. Internally uses
 * {@link ParcelFileDescriptor#checkError()} to verify that content arrives
 * without errors. Writes to temporary file to keep atomic view of contents,
 * swapping into place only when write is successful.
 * <p/>//from w w  w .  j  ava2 s.  c o  m
 * Pipe is left open, so caller is responsible for calling
 * {@link ParcelFileDescriptor#close()} or
 * {@link ParcelFileDescriptor#closeWithError(String)}.
 *
 * @param contentIn read end of a pipe.
 */
public void writeMetadataAndContent(JSONObject meta, ParcelFileDescriptor contentIn)
        throws IOException, GeneralSecurityException {
    // Write into temporary file to provide an atomic view of existing
    // contents during write, and also to recover from failed writes.
    final String tempName = mFile.getName() + ".tmp_" + Thread.currentThread().getId();
    final File tempFile = new File(mFile.getParentFile(), tempName);

    RandomAccessFile f = new RandomAccessFile(tempFile, "rw");
    try {
        // Truncate any existing data
        f.setLength(0);

        // Write content first to detect size
        if (contentIn != null) {
            f.seek(CONTENT_OFFSET);
            final int plainLength = writeSection(f, new FileInputStream(contentIn.getFileDescriptor()));
            meta.put(Document.COLUMN_SIZE, plainLength);

            // Verify that remote side of pipe finished okay; if they
            // crashed or indicated an error then this throws and we
            // leave the original file intact and clean up temp below.
            contentIn.checkError();
        }

        meta.put(Document.COLUMN_DOCUMENT_ID, mDocId);
        meta.put(Document.COLUMN_LAST_MODIFIED, System.currentTimeMillis());

        // Rewind and write metadata section
        f.seek(0);
        f.writeInt(MAGIC_NUMBER);

        final ByteArrayInputStream metaIn = new ByteArrayInputStream(
                meta.toString().getBytes(StandardCharsets.UTF_8));
        writeSection(f, metaIn);

        if (f.getFilePointer() > CONTENT_OFFSET) {
            throw new IOException("Metadata section was too large");
        }

        // Everything written fine, atomically swap new data into place.
        // fsync() before close would be overkill, since rename() is an
        // atomic barrier.
        f.close();
        tempFile.renameTo(mFile);

    } catch (JSONException e) {
        throw new IOException(e);
    } finally {
        // Regardless of what happens, always try cleaning up.
        f.close();
        tempFile.delete();
    }
}

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From source file:com.aol.advertising.qiao.injector.file.AbstractFileReader.java

protected long checksum(RandomAccessFile raFile) throws IOException, IllegalStateException {
    long pos = raFile.getFilePointer();
    try {/*  ww  w.  j av a2s  . c o m*/
        byte[] buffer = new byte[checksumByteLength];
        raFile.seek(0);
        int n = raFile.read(buffer);
        if (n < checksumByteLength) {
            String s;
            logger.warn(s = ("not enough data for checksum: current file size=" + n));
            throw new IllegalStateException(s);
        }

        synchronized (_crc) {
            _crc.reset();
            _crc.update(buffer);

            return _crc.getValue();
        }
    } finally {
        raFile.seek(pos);
    }

}

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

/**
 * Decrypt and read content section of this document, writing it into the
 * given pipe.//  w  ww .j  a  v a  2s  .co m
 * <p/>
 * Pipe is left open, so caller is responsible for calling
 * {@link ParcelFileDescriptor#close()} or
 * {@link ParcelFileDescriptor#closeWithError(String)}.
 *
 * @param contentOut write end of a pipe.
 * @throws DigestException if content fails MAC check. Some or all content
 *                         may have already been written to the pipe when the MAC is
 *                         validated.
 */
public void readContent(ParcelFileDescriptor contentOut) throws IOException, GeneralSecurityException {
    final RandomAccessFile f = new RandomAccessFile(mFile, "r");
    try {
        assertMagic(f);

        if (f.length() <= CONTENT_OFFSET) {
            throw new IOException("Document has no content");
        }

        // Skip over metadata section
        f.seek(CONTENT_OFFSET);
        readSection(f, new FileOutputStream(contentOut.getFileDescriptor()));

    } finally {
        f.close();
    }
}

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From source file:org.pentaho.platform.web.servlet.UploadFileUtils.java

/**
 * Gets the uncompressed file size of a .gz file by reading the last four bytes of the file
 * /*  w  w  w  .  j  av  a  2  s  .c om*/
 * @param file
 * @return long uncompressed original file size
 * @throws IOException
 *           mbatchelor
 */
private long getUncompressedGZipFileSize(File file) throws IOException {
    long rtn = 0;
    RandomAccessFile gzipFile = new RandomAccessFile(file, "r");
    try {
        // go 4 bytes from end of file - the original uncompressed file size is there
        gzipFile.seek(gzipFile.length() - 4);
        byte[] intelSize = new byte[4];
        gzipFile.read(intelSize); // read the size ....
        // rfc1952; ISIZE is the input size modulo 2^32
        // 00F01E69 is really 691EF000
        // The &0xFF turns signed byte into unsigned.
        rtn = (((intelSize[3] & 0xFF) << 24)
                | ((intelSize[2] & 0xFF) << 16) + ((intelSize[1] & 0xFF) << 8) + (intelSize[0] & 0xFF))
                & 0xffffffffL;
    } finally {
        try {
            gzipFile.close();
        } catch (Exception ignored) {
            //ignored
        }
    }
    return rtn;
}

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From source file:com.csipsimple.service.DownloadLibService.java

private boolean installRemoteLib(RemoteLibInfo lib) {
    String fileName = lib.getFileName();
    File filePath = lib.getFilePath();

    File tmp_gz = new File(filePath, fileName + ".gz");
    File dest = new File(filePath, fileName);

    try {//  w w w  .  ja v a 2 s  .  c o  m
        if (dest.exists()) {
            dest.delete();
        }
        RandomAccessFile out = new RandomAccessFile(dest, "rw");
        out.seek(0);
        GZIPInputStream zis = new GZIPInputStream(new FileInputStream(tmp_gz));
        int len;
        byte[] buf = new byte[BUFFER];
        while ((len = zis.read(buf)) > 0) {
            out.write(buf, 0, len);
        }
        zis.close();
        out.close();
        Log.d(THIS_FILE, "Ungzip is in : " + dest.getAbsolutePath());
        tmp_gz.delete();
        //Update preferences fields with current stack values
        Editor editor = prefs.edit();
        editor.putString(CURRENT_STACK_ID, lib.getId());
        editor.putString(CURRENT_STACK_VERSION, lib.getVersion());
        editor.putString(CURRENT_STACK_URI, lib.getDownloadUri().toString());
        editor.commit();
        return true;
    } catch (IOException e) {
        Log.e(THIS_FILE, "We failed to install it ", e);
    }
    return false;
}

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From source file:org.ngrinder.perftest.service.AgentManager.java

@Override
public synchronized AgentUpdateGrinderMessage onAgentDownloadRequested(String version, int offset) {
    final int updateChunkSize = getUpdateChunkSize();
    byte[] buffer = new byte[updateChunkSize];
    RandomAccessFile agentPackageReader = null;
    try {/*from w  w w .j  a v a2  s .com*/
        agentPackageReader = new RandomAccessFile(agentPackageService.createAgentPackage(), "r");
        agentPackageReader.seek(offset);
        int count = agentPackageReader.read(buffer, 0, updateChunkSize);
        byte[] bytes = buffer;
        int next = offset + count;
        if (count != updateChunkSize) {
            bytes = Arrays.copyOf(buffer, count);
            next = 0;
        }
        return new AgentUpdateGrinderMessage(version, bytes, offset, next,
                CRC32ChecksumUtils.getCRC32Checksum(bytes));
    } catch (Exception e) {
        LOGGER.error("Error while reading agent package, its offset is {} and details {}:", offset, e);
    } finally {
        IOUtils.closeQuietly(agentPackageReader);
    }
    return AgentUpdateGrinderMessage.getNullAgentUpdateGrinderMessage(version);
}

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From source file:com.frand.easyandroid.http.FFFileRespHandler.java

public int copy(InputStream input, RandomAccessFile out) throws IOException {
    interrupt = false;// w ww  . j av  a 2 s  .c o m
    if (input == null || out == null) {
        return -1;
    }
    byte[] buffer = new byte[BUFFER_SIZE];
    BufferedInputStream in = new BufferedInputStream(input, BUFFER_SIZE);
    int count = 0, n = 0;
    long errorBlockTimePreviousTime = -1, expireTime = 0;
    try {
        out.seek(out.length());
        previousTime = System.currentTimeMillis();
        while (!interrupt) {
            n = in.read(buffer, 0, BUFFER_SIZE);
            if (n == -1) {
                break;
            }
            out.write(buffer, 0, n);
            count += n;
            if (networkSpeed == 0) {
                if (errorBlockTimePreviousTime > 0) {
                    expireTime = System.currentTimeMillis() - errorBlockTimePreviousTime;
                    if (expireTime > TIME_OUT) {
                        throw new ConnectTimeoutException("connection time out.");
                    }
                } else {
                    errorBlockTimePreviousTime = System.currentTimeMillis();
                }
            } else {
                expireTime = 0;
                errorBlockTimePreviousTime = -1;
            }
        }
    } finally {
        try {
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return count;
}

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From source file:org.xwalk.runtime.extension.api.device_capabilities.DeviceCapabilitiesCPU.java

/**
 * The algorithm here can be found at://from  w  w  w .  j a v a  2s  .c  om
 * http://stackoverflow.com/questions/3017162/how-to-get-total-cpu-usage-in-linux-c
 */
private boolean getCPULoad() {
    try {
        RandomAccessFile file = new RandomAccessFile(SYSTEM_INFO_STAT_FILE, "r");
        String line = file.readLine();

        String[] arrs = line.split("\\s+");
        long total1 = 0;
        for (int i = 1; i < arrs.length; ++i) {
            total1 += Long.parseLong(arrs[i]);
        }
        // arrs[4] is the time spent in idle tasks.
        long used1 = total1 - Long.parseLong(arrs[4]);
        try {
            Thread.sleep(1000);
        } catch (Exception e) {
            mCPULoad = 0.0;
            return false;
        }

        file.seek(0);
        line = file.readLine();
        file.close();

        arrs = line.split("\\s+");
        long total2 = 0;
        for (int i = 1; i < arrs.length; ++i) {
            total2 += Long.parseLong(arrs[i]);
        }
        // arrs[4] is the time spent in idle tasks.
        long used2 = total2 - Long.parseLong(arrs[4]);
        if (total2 == total1) {
            mCPULoad = 0.0;
        } else {
            mCPULoad = (double) (used2 - used1) / (total2 - total1);
        }
    } catch (IOException e) {
        mCPULoad = 0.0;
        return false;
    }
    return true;
}

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