Examples with FileTailInfo com.axway.ats.common.filesystem.FileTailInfo used on opensource projects

Example 1 with FileTailInfo

use of com.axway.ats.common.filesystem.FileTailInfo in project ats-framework by Axway.

the class LocalFileSystemOperations method readFile.

/**
     * Read file from specific position. Used for file tail.<br/>
     *
     * <b>NOTE:</b> If the file is replaced with the same byte content, then no change is assumed and 'null' is returned
     *
     * @param fileName file name
     * @param fromBytePosition byte offset. Example: for already read 100 bytes next method call is expected to have 100 as value for this parameter
     * return  {@link FileTailInfo} object
     */
public FileTailInfo readFile(String fileName, long fromBytePosition) {
    RandomAccessFile reader = null;
    try {
        long position = 0;
        boolean isFileRotated = false;
        // Open the file for read only
        File file = new File(fileName);
        try {
            reader = new RandomAccessFile(file, "r");
        } catch (FileNotFoundException fne) {
            throw new FileSystemOperationException("File '" + fileName + "' not found.", fne);
        }
        long length = file.length();
        if (length < fromBytePosition) {
            // File was rotated
            isFileRotated = true;
            position = 0;
        } else {
            position = fromBytePosition;
        }
        reader.seek(position);
        String line = IoUtils.readLineWithEOL(reader);
        if (line != null) {
            StringBuilder sb = new StringBuilder(line.length());
            while (line != null) {
                sb.append(line);
                //TODO: consider file encoding
                line = IoUtils.readLineWithEOL(reader);
            }
            position = reader.getFilePointer();
            return new FileTailInfo(position, isFileRotated, sb.toString());
        }
    } catch (Exception e) {
        throw new FileSystemOperationException("Could not read file '" + fileName + "' from byte position " + fromBytePosition, e);
    } finally {
        IoUtils.closeStream(reader);
    }
    return null;
}