QueryStringEncoder Class — netty Architecture

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/QueryStringEncoder.java lines 40–250

public class QueryStringEncoder {

    private final Charset charset;
    private final StringBuilder uriBuilder;
    private boolean hasParams;
    private static final byte WRITE_UTF_UNKNOWN = (byte) '?';
    private static final char[] CHAR_MAP = "0123456789ABCDEF".toCharArray();

    /**
     * Creates a new encoder that encodes a URI that starts with the specified
     * path string.  The encoder will encode the URI in UTF-8.
     */
    public QueryStringEncoder(String uri) {
        this(uri, HttpConstants.DEFAULT_CHARSET);
    }

    /**
     * Creates a new encoder that encodes a URI that starts with the specified
     * path string in the specified charset.
     */
    public QueryStringEncoder(String uri, Charset charset) {
        ObjectUtil.checkNotNull(charset, "charset");
        uriBuilder = new StringBuilder(uri);
        this.charset = CharsetUtil.UTF_8.equals(charset) ? null : charset;
    }

    /**
     * Adds a parameter with the specified name and value to this encoder.
     */
    public void addParam(String name, String value) {
        ObjectUtil.checkNotNull(name, "name");
        if (hasParams) {
            uriBuilder.append('&');
        } else {
            uriBuilder.append('?');
            hasParams = true;
        }

        encodeComponent(name);
        if (value != null) {
            uriBuilder.append('=');
            encodeComponent(value);
        }
    }

    private void encodeComponent(CharSequence s) {
        if (charset == null) {
            encodeUtf8Component(s);
        } else {
            encodeNonUtf8Component(s);
        }
    }

    /**
     * Returns the URL-encoded URI object which was created from the path string
     * specified in the constructor and the parameters added by
     * {@link #addParam(String, String)} method.
     */
    public URI toUri() throws URISyntaxException {
        return new URI(toString());
    }

    /**
     * Returns the URL-encoded URI which was created from the path string
     * specified in the constructor and the parameters added by
     * {@link #addParam(String, String)} method.
     */
    @Override
    public String toString() {
        return uriBuilder.toString();
    }

    /**
     * Encode the String as per RFC 3986, Section 2.
     * <p>
     * There is a little different between the JDK's encode method : {@link URLEncoder#encode(String, String)}.
     * The JDK's encoder encode the space to {@code +} and this method directly encode the blank to {@code %20}
     * beyond that , this method reuse the {@link #uriBuilder} in this class rather then create a new one,
     * thus generates less garbage for the GC.
     *
     * @param s The String to encode