InputStream parser for the Twitter streaming API.

StreamParser.java

package com.showyou.importer.twitter;

import java.io.IOException;
import java.io.InputStream;

/**
 * Created by Phil Kulak
 * Date: 1/1/12
 *
 * Parses an InputStream from the Twitter site streams API. The stream needs to be length-delimited (?delimited=length)
 */
public class StreamParser {
    private InputStream inputStream;

    public StreamParser(InputStream stream) {
        inputStream = stream;
    }

    public String read() throws IOException, InterruptedException {
        if (Thread.interrupted()) {
            inputStream.close();
            throw new InterruptedException();
        }

        int currentByte = inputStream.read();
        StringBuilder byteCountString = new StringBuilder();

        // Slip ahead to the next integer (to skip keep alives)
        while (currentByte >= 58 || currentByte <= 47) {
            currentByte = inputStream.read();
        }

        // Grab the byte count.
        while (currentByte < 58 && currentByte > 47) {
            byteCountString.append(new String(new byte[] {(byte) currentByte}));
            currentByte = inputStream.read();
        }

        int byteCount = Integer.parseInt(byteCountString.toString());

        // Swallow the \n.
        inputStream.skip(1);

        // Adjust the byte count to avoid the \r\n\r\n at the end
        byteCount -= 4;

        // Get the string.
        byte[] buffer = new byte[byteCount];
        inputStream.read(buffer);
        String json = new String(buffer, "UTF-8");

        // Swallow the \r\n\r\n
        inputStream.skip(4);

        return json;
    }
}