Java: Javolution: How to use UTF8StreamReader properly? Error occurs Caused by: java.lang.ArrayIndexOutOfBoundsException: 2048

Question

Here's the code:

public static void mergeAllFilesJavolution()throws FileNotFoundException, IOException {
    String fileDir = "C:\\TestData\\w12";
    File dirSrc = new File(fileDir);
    File[] list = dirSrc.listFiles();
    long start = System.currentTimeMillis();
    for(int j=0; j<list.length; j++){
        int chr;
        String srcFile = list[j].getPath();
        String outFile = fileDir + "\\..\\merged.txt";
        UTF8StreamReader inFile=new UTF8StreamReader().setInput(new FileInputStream(srcFile));
        UTF8StreamWriter outPut=new UTF8StreamWriter().setOutput(new FileOutputStream(outFile, true)); 
        while((chr=inFile.read()) != -1) {
            outPut.write(chr);
        }
        outPut.close();
        inFile.close();
    }
    System.out.println(System.currentTimeMillis()-start);
}

File size of the utf-8 file is 200MB as test data but high possibility of 800MB up.

Here's the UTF8StreamReader.read() source code.

/**
 * Holds the bytes buffer.
 */
private final byte[] _bytes;

/**
 * Creates a UTF-8 reader having a byte buffer of moderate capacity (2048).
 */
public UTF8StreamReader() {
    _bytes = new byte[2048];
}

/**
 * Reads a single character.  This method will block until a character is
 * available, an I/O error occurs or the end of the stream is reached.
 *
 * @return the 31-bits Unicode of the character read, or -1 if the end of
 *         the stream has been reached.
 * @throws IOException if an I/O error occurs.
 */
public int read() throws IOException {
    byte b = _bytes[_start];
    return ((b >= 0) && (_start++ < _end)) ? b : read2();
}

The error occurs at _bytes[_start] because the _bytes = new byte[2048].

Here's another UTF8StreamReader constructor:

/**
 * Creates a UTF-8 reader having a byte buffer of specified capacity.
 * 
 * @param capacity the capacity of the byte buffer.
 */
public UTF8StreamReader(int capacity) {
    _bytes = new byte[capacity];
}

Problem: How can I specified the correct capacity of the _bytes upon UTF8StreamReader creation?

I tried the File.length() but it returns long type (i think its right because I am expecting huge file size but the constructor receiving only by int type).

Any guidance on the right direction is appreciated.

Answer 1

It seems anybody does not yet experience same with the above situation.

Anyway, I tried other solution by not using the above class (UTF8StreamReader) rather ByteBuffer (UTF8ByteBufferReader). It is incredible faster than StreamReader.

Faster Merging Files by using ByteBuffer