private static <T> void setImplementation(Class<T> type, Class<? extends T> implementation) {
    checkArgument(type != implementation, "Don't register %s to itself!", type);
    checkArgument(
        !DEFAULTS.containsKey(type), "A default value was already registered for %s", type);
    checkArgument(
        implementations.put(type, implementation) == null,
        "Implementation for %s was already registered",

public class PreconditionsTest extends TestCase {
  public void testCheckArgument_simple_success() {
    checkArgument(true);
  }

  public void testCheckArgument_simple_failure() {
    assertThrows(IllegalArgumentException.class, () -> checkArgument(false));
  }

  public void testCheckArgument_simpleMessage_success() {
    checkArgument(true, IGNORE_ME);
  }

  public void testCheckArgument_simpleMessage_failure() {

   *     of range.
   */
  public static HostAndPort fromParts(String host, int port) {
    checkArgument(isValidPort(port), "Port out of range: %s", port);
    HostAndPort parsedHost = fromString(host);
    checkArgument(!parsedHost.hasPort(), "Host has a port: %s", host);
    return new HostAndPort(parsedHost.host, port, parsedHost.hasBracketlessColons);
  }

  /**

      long loadSuccessCount,
      long loadExceptionCount,
      long totalLoadTime,
      long evictionCount) {
    checkArgument(hitCount >= 0);
    checkArgument(missCount >= 0);
    checkArgument(loadSuccessCount >= 0);
    checkArgument(loadExceptionCount >= 0);
    checkArgument(totalLoadTime >= 0);
    checkArgument(evictionCount >= 0);

    this.hitCount = hitCount;
    this.missCount = missCount;

      long loadSuccessCount,
      long loadExceptionCount,
      long totalLoadTime,
      long evictionCount) {
    checkArgument(hitCount >= 0);
    checkArgument(missCount >= 0);
    checkArgument(loadSuccessCount >= 0);
    checkArgument(loadExceptionCount >= 0);
    checkArgument(totalLoadTime >= 0);
    checkArgument(evictionCount >= 0);

    this.hitCount = hitCount;
    this.missCount = missCount;

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

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.Sets.newHashSet;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;

    }

    @Override
    public SortedMap<C, V> subMap(C fromKey, C toKey) {
      checkArgument(rangeContains(checkNotNull(fromKey)) && rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, fromKey, toKey);
    }

    @Override
    public SortedMap<C, V> headMap(C toKey) {
      checkArgument(rangeContains(checkNotNull(toKey)));
      return new TreeRow(rowKey, lowerBound, toKey);
    }

          Class<?>[] parameterTypes = method.getParameterTypes();
          checkArgument(
              parameterTypes.length == 1,
              "Method %s has @Subscribe annotation but has %s parameters. "
                  + "Subscriber methods must have exactly 1 parameter.",
              method,
              parameterTypes.length);

          checkArgument(
              !parameterTypes[0].isPrimitive(),

              uncheckedCastNullableTToT(lowerEndpoint), uncheckedCastNullableTToT(upperEndpoint));
      // be consistent with Range
      checkArgument(
          cmp <= 0, "lowerEndpoint (%s) > upperEndpoint (%s)", lowerEndpoint, upperEndpoint);
      if (cmp == 0) {
        checkArgument(lowerBoundType != OPEN || upperBoundType != OPEN);
      }
    }
  }

  Comparator<? super T> comparator() {
    return comparator;

  }

  @VisibleForTesting
  static void checkExceptionClassValidity(Class<? extends Exception> exceptionClass) {
    checkArgument(
        isCheckedException(exceptionClass),
        "Futures.getChecked exception type (%s) must not be a RuntimeException",
        exceptionClass);
    checkArgument(
        hasConstructorUsableByGetChecked(exceptionClass),