Convert Reader to InputStream : InputStream « File Input Output « Java

Convert Reader to InputStream

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* This class convert Reader to InputStream. It works by converting
* the characters to the encoding specified in constructor parameter.
* @author   Petr Hamernik, David Strupl
public class ReaderInputStream extends InputStream {
    /** Input Reader class. */
    private Reader reader;
    private PipedOutputStream pos;
    private PipedInputStream pis;
    private OutputStreamWriter osw;

    /** Creates new input stream from the given reader.
     * Uses the platform default encoding.
    * @param reader Input reader
    public ReaderInputStream(Reader reader) throws IOException {
        this.reader = reader;
        pos = new PipedOutputStream();
        pis = new PipedInputStream(pos);
        osw = new OutputStreamWriter(pos);

    /** Creates new input stream from the given reader and encoding.
     * @param reader Input reader
     * @param encoding
    public ReaderInputStream(Reader reader, String encoding)
    throws IOException {
        this.reader = reader;
        pos = new PipedOutputStream();
        pis = new PipedInputStream(pos);
        osw = new OutputStreamWriter(pos, encoding);

    public int read() throws IOException {
        if (pis.available() > 0) {

        int c =;

        if (c == -1) {
            return c;



    public int read(byte[] b, int off, int len) throws IOException {
        if (len == 0) {
            return 0;

        int c = read();

        if (c == -1) {
            return -1;

        b[off] = (byte) c;

        int i = 1;

        // Don't try to fill up the buffer if the reader is waiting.
        for (; (i < len) && reader.ready(); i++) {
            c = read();

            if (c == -1) {
                return i;

            b[off + i] = (byte) c;

        return i;

    public int available() throws IOException {
        int i = pis.available();

        if (i > 0) {
            return i;

        if (reader.ready()) {
            // Char must produce at least one byte.
            return 1;
        } else {
            return 0;

    public void close() throws IOException {


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