UrlEncodedMessage.java

package com.googlecode.totallylazy;

import com.googlecode.totallylazy.functions.Function1;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

import static com.googlecode.totallylazy.Pair.pair;
import static com.googlecode.totallylazy.Sequences.sequence;
import static com.googlecode.totallylazy.Strings.UTF8;

public class UrlEncodedMessage {
    public static List<Pair<String, String>> parse(String value) {
        List<Pair<String, String>> result = new ArrayList<Pair<String, String>>();
        if (Strings.isEmpty(value)) {
            return result;
        }

        for (String pair : value.split("&")) {
            if(!pair.contains("=")) {
                result.add(Pair.<String, String>pair(decode(pair), null));
                continue;
            }
            String[] nameValue = pair.split("=");
            if (nameValue.length == 1) {
                result.add(Pair.<String, String>pair(decode(nameValue[0]), ""));
                continue;
            }
            if (nameValue.length == 2) {
                result.add(pair(decode(nameValue[0]), decode(nameValue[1])));
            }
        }
        return result;
    }

    public static String toString(Iterable<? extends Pair<String, String>> pairs) {
        return sequence(pairs).map(pair -> {
            if(pair.second() == null) return encode(pair.first());
            return encode(pair.first()) + "=" + encode(pair.second());
        }).toString("&");
    }


    public static String decode(String value) {
        try {
            return URLDecoder.decode(value, UTF8.toString());
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

    public static String encode(String value) {
        if (value == null) return null;
        try {
            return URLEncoder.encode(value, UTF8.toString());
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

    public static class functions {
        public static Function1<String, String> encode() {
            return UrlEncodedMessage::encode;
        }

        public static Function1<String, String> decode() {
            return UrlEncodedMessage::decode;
        }
    }
}