* See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import okio.IOException

/**
 * Protocols that OkHttp implements for [ALPN][ietf_alpn] selection.
 *
 * ## Protocol vs Scheme
 *
 * Despite its name, [java.net.URL.getProtocol] returns the [scheme][java.net.URI.getScheme] (http,

     */
    public boolean isUsableForChannel() {
        return address != null && !address.isLoopbackAddress() && !address.isLinkLocalAddress();
    }

    /**
     * Get a score for interface selection (higher is better)
     *
     * @return interface score
     */
    public int getScore() {
        int score = linkSpeed; // Base score is link speed

        if (rssCapable)

        int expected = input & 0xFF;
        assertEquals(expected, ns.value, "value should be masked to 0xFF before storing");
    }

    /**
     * Round-trip encode/decode for a selection of representative values.
     */
    @ParameterizedTest
    @ValueSource(ints = { 0, 42, 255, -1, 128 })
    void encodeDecodeRoundTrip(int original) throws Exception {
        // The constructor masks to 0xFF (8 bits)

 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of
 * {@code com.google.common.util.concurrent}) in degenerate class loaders which make certain

        for (LoadBalancingStrategy strategy : strategies) {
            loadBalancer.setStrategy(strategy);
            assertEquals(strategy, loadBalancer.getStrategy());
        }

        // Test channel selection with mock request when no channels available
        ServerMessageBlock2Request mockRequest = mock(ServerMessageBlock2Request.class);
        when(mockRequest.getTreeId()).thenReturn(123);

            List<ChannelInfo> list = new ArrayList<>(channels);
            return list.get(ThreadLocalRandom.current().nextInt(list.size()));
        }

        // Weighted random selection
        int random = ThreadLocalRandom.current().nextInt(totalWeight);
        int currentWeight = 0;

        for (ChannelInfo channel : channels) {
            currentWeight += channel.getScore();

 * selected in the static initializer of AbstractFuture. This is convenient and performant but
 * introduces some testing difficulties. This test exercises the fallback strategies.
 *
 * <p>To force selection of our fallback strategies, we load {@link AbstractFuture} (and all of
 * {@code com.google.common.util.concurrent}) in degenerate class loaders which make certain

 * if it is present on the connection spec. The same policy also applies to cipher suites.
 *
 * Use [Builder.allEnabledTlsVersions] and [Builder.allEnabledCipherSuites] to defer all feature
 * selection to the underlying SSL socket.
 *
 * The configuration of each spec changes with each OkHttp release. This is annoying: upgrading
 * your OkHttp library can break connectivity to certain web servers! But it’s a necessary annoyance

  fun recordedConnectionEventTypes(): List<String> = connectionListener.recordedEventTypes()

  companion object {
    /**
     * A network that resolves only one IP address per host. Use this when testing route selection
     * fallbacks to prevent the host machine's various IP addresses from interfering.
     */
    private val SINGLE_INET_ADDRESS_DNS =
      Dns { hostname ->
        val addresses = Dns.SYSTEM.lookup(hostname)

 *  Fix: Don't track unusable routes beyond their usefulness. We had a bug where we could track
    certain bad routes indefinitely; now we only track the ones that could be necessary.
 *  Fix: Defer proxy selection until a proxy is required. This saves calls to `ProxySelector` on
    calls that use a pooled connection.


## Version 4.3.1

_2020-01-07_