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(byte b[]) throws IOException 

Source Link

Document

Reads up to b.length bytes of data from this file into an array of bytes.

Usage

From source file:aarddict.Volume.java

Article readArticle(long pointer) throws IOException {
    Article a = articleCache.get(pointer);
    if (a != null)
        return a;
    Header h = this.header;
    long pos = h.articleOffset + pointer;
    RandomAccessFile f = this.file;
    f.seek(pos);//from ww w . jav  a2s  .  c  o  m
    long articleLength = f.readSpec(h.articleLengthSpec);

    byte[] articleBytes = new byte[(int) articleLength];
    f.read(articleBytes);
    String serializedArticle = decompress(articleBytes);
    a = Article.fromJsonStr(serializedArticle);
    a.dictionaryUUID = h.uuid;
    a.volumeId = h.sha1sum;
    a.pointer = pointer;
    articleCache.put(pointer, a);
    return a;
}

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From source file:cern.acet.tracing.input.file.tailer.PositionTailer.java

/**
 * Read new lines./*from  ww  w .  j av a2  s .  co  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 {
    StringBuilder sb = new StringBuilder();

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

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

        pos = reader.getFilePointer();
    }

    reader.seek(rePos); // Ensure we can re-read if necessary
    listener.positionUpdated(pos);
    return rePos;
}

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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 {/*from   ww  w .j a  v a2 s .  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:at.tuwien.minimee.util.TopParser.java

/**
 * The process ID is in the last line of the file and looks like follows:
 * monitored_pid= 6738 /*from  www.j  a v a2 s .  com*/
 * 
 * @param input
 * @return
 * @throws Exception
 */
private Integer findPid() throws Exception {

    Integer pid = new Integer(0);

    // we open the file
    RandomAccessFile f = new RandomAccessFile(file, "r");

    try {

        long size = f.length();

        f.seek(size - 2);

        // we search the file reverse for '='
        byte[] b = new byte[1];
        for (long i = size - 2; i >= 0; i--) {
            f.seek(i);
            f.read(b);
            if (b[0] == '=') {
                break;
            }
        }

        String line = f.readLine().trim();

        pid = new Integer(line);

    } finally {
        // this is important, RandomAccessFile doesn't close the file handle by default!
        // if close isn't called, you'll get very soon 'too many open files'
        f.close();
    }

    return pid;
}

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From source file:org.everit.osgi.dev.maven.util.FileManager.java

public byte[] tryReadingAmount(final RandomAccessFile is, final int amount) throws IOException {
    ByteArrayOutputStream bout = new ByteArrayOutputStream(amount);
    byte[] buffer = new byte[amount];
    int r = is.read(buffer);
    while ((r > -1) && (bout.size() < amount)) {
        bout.write(buffer, 0, r);/* w  w w  . java 2s. com*/
        r = is.read(buffer, 0, amount - bout.size());
    }
    return bout.toByteArray();
}

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From source file:org.kawanfw.file.servlet.util.FileTransferManager.java

/**
 * Copy the content of the random access file to the output stream up to a
 * chubk length// w  w w. j  a  va2 s  . c om
 * 
 * @param raf
 * @param out
 * @param chunkLength
 * @return the total amount read
 * 
 * @throws IOException
 */
private long copy(RandomAccessFile raf, OutputStream out, long chunkLength) throws IOException {
    int writeBufferSize = DefaultParms.DEFAULT_WRITE_BUFFER_SIZE;

    // For Chunk Length comparison. If buffer read > chunk
    // length ==> exit
    long totalRead = 0;

    byte[] tmp = new byte[writeBufferSize];
    int len;

    while ((len = raf.read(tmp)) >= 0) {
        totalRead += len;
        out.write(tmp, 0, len);

        // Exit if chunk length is reached. We will just send
        // the chunck,InputStream will be reused
        if (chunkLength > 0 && totalRead > chunkLength - writeBufferSize) {
            return totalRead;
        }
    }

    return totalRead;
}

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From source file:com.polyvi.xface.extension.advancedfiletransfer.FileUploader.java

/**
 * ?buffer?,??//from ww w  . java2s  .com
 *
 * @param buffer
 *            :??
 */
private int readFileData(byte[] buffer) {
    int len = READ_FILE_END;
    RandomAccessFile accessFile = null;
    try {
        accessFile = new RandomAccessFile(mUploadFile, "r");
        accessFile.seek(mStartedPosition);
        len = accessFile.read(buffer);
        if (mStartedPosition != mAlreadyUploadLength) {
            mAlreadyUploadLength = mStartedPosition;
        }
        accessFile.close();
    } catch (FileNotFoundException e) {
        len = READ_FILE_END;
        onError(FILE_NOT_FOUND_ERR);
    } catch (IOException e) {
        len = READ_FILE_END;
        onError(FILE_NOT_FOUND_ERR);
    }
    return len;
}

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From source file:com.excuseme.rocketleaguelivestats.scanner.tailer.Tailer.java

/**
 * Read new lines./*from   w  w  w  . java2  s  .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 {
    StringBuilder sb = new StringBuilder();

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

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

        pos = reader.getFilePointer();
    }
    if (reader.read(inbuf) == -1) {
        listener.endOfFile();
    }

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

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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
 * //from w  w w.ja  va  2s . co m
 * @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:org.scriptbox.util.common.io.Tailer.java

/**
 * Read new lines.// w  ww. j a  va2s .co  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 {
    StringBuilder sb = new StringBuilder();

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

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

        pos = reader.getFilePointer();
    }

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

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