package api;

import java.io.IOException;

/**

 *

 * @author Jaroslav Tulach

 */

final class SimpleBuffer implements Writer.ImplSeq {

    private final Writer out;

    private final StringBuffer sb = new StringBuffer();

    public SimpleBuffer(Writer out) {

        this.out = out;

    }

    public void close() throws IOException {

        flush();

        out.close();

    }

    public void flush() throws IOException {

        if (sb.length() > 0) {

            out.write(sb.toString());

            sb.setLength(0);

            out.flush();

        }

    }

    public void write(CharSequence seq) throws IOException {

        if (shouldBufferAsTheSequenceIsNotTooBig(seq)) {

            sb.append(seq);

        } else {

            flush();

            out.append(seq);

        }

    }

    /** At the end the purpose of BufferedWriter is to buffer writes, this

     * method is here to decide when it is OK to prefer buffering and when 

     * it is better to delegate directly into the underlaying stream.

     * 

     * @param csq the seqence to evaluate

     * @return true if buffering from super class should be used

     */

    private static boolean shouldBufferAsTheSequenceIsNotTooBig(CharSequence csq) {

        if (csq == null) {

            return false;

        }

        // as buffers are usually bigger than 1024, it makes sense to 

        // pay the penalty of converting the sequence to string, but buffering

        // the write

        if (csq.length() < 1024) {

            return true;

        } else {

            // otherwise, just directly write down the char sequence

            return false;

        }

    }

}