HttpCodes.java

package com.example.util;

import android.support.annotation.NonNull;

import java.util.ArrayList;
import java.util.List;

import static java.util.Arrays.asList;
import static java.util.Collections.unmodifiableList;

/**
 * From Quality Matters project. See https://github.com/artem-zinnatullin/qualitymatters.
 */
public final class HttpCodes {

    // https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#4xx_Client_Error
    private static final List<Integer> CLIENT_SIDE_ERROR_CODES = unmodifiableList(asList(
            400,
            401,
            402,
            403,
            404,
            405,
            406,
            // For 408, OkHttp will do silent retry.
            409,
            410,
            411,
            412,
            413,
            414,
            415,
            416,
            417,
            418,
            422,
            423,
            424,
            426,
            428,
            429,
            431,
            440
    ));

    // https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_Server_Error
    private static final List<Integer> SERVER_SIDE_ERROR_CODES = unmodifiableList(asList(
            500,
            501,
            502,
            503,
            504,
            505,
            506,
            507,
            508,
            509,
            510,
            511
    ));

    private static final List<Integer> CLIENT_AND_SERVER_ERROR_CODES;

    static {
        List<Integer> clientAndServerErrorCodes = new ArrayList<>(CLIENT_SIDE_ERROR_CODES.size() + SERVER_SIDE_ERROR_CODES.size());
        clientAndServerErrorCodes.addAll(CLIENT_SIDE_ERROR_CODES);
        clientAndServerErrorCodes.addAll(SERVER_SIDE_ERROR_CODES);

        CLIENT_AND_SERVER_ERROR_CODES = unmodifiableList(clientAndServerErrorCodes);
    }

    private HttpCodes() {
        throw new AssertionError();
    }

    @NonNull
    public static List<Integer> clientAndServerSideErrorCodes() {
        return CLIENT_AND_SERVER_ERROR_CODES;
    }

}