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() {

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

package com.google.common.graph;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static com.google.common.graph.GraphConstants.ENDPOINTS_MISMATCH;

 * 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.base.Preconditions.checkNotNull;
import static com.google.common.collect.CollectPreconditions.checkNonnegative;

import com.google.common.annotations.GwtCompatible;

     * identical, the transformation is horizontal (i.e. the slope is zero).
     */
    public LinearTransformation and(double x2, double y2) {
      checkArgument(isFinite(x2) && isFinite(y2));
      if (x2 == x1) {
        checkArgument(y2 != y1);
        return new VerticalLinearTransformation(x1);
      } else {
        return withSlope((y2 - y1) / (x2 - x1));
      }
    }

    /**

        }
      }
      return 0;
    }

    @Override
    public int add(E element, int occurrences) {
      checkArgument(occurrences >= 0);
      Integer frequency = backingMap.getOrDefault(element, 0);
      if (occurrences == 0) {
        return frequency;
      }
      checkArgument(occurrences <= Integer.MAX_VALUE - frequency);
      backingMap.put(element, frequency + occurrences);
      return frequency;

    checkNotNull(that);
    checkArgument(this != that, "Cannot combine a BloomFilter with itself.");
    checkArgument(
        this.numHashFunctions == that.numHashFunctions,
        "BloomFilters must have the same number of hash functions (%s != %s)",
        this.numHashFunctions,
        that.numHashFunctions);
    checkArgument(
        this.bitSize() == that.bitSize(),

  }

  @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),

 * 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.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.Tables.transformValues;

import com.google.common.annotations.GwtCompatible;

    }
    checkArgument(!map.isEmpty());
    return getDeclaringClassOrObjectForJ2cl(map.keySet().iterator().next());
  }

  private static <V extends Enum<V>> Class<V> inferValueTypeOrObjectUnderJ2cl(Map<?, V> map) {
    if (map instanceof EnumBiMap) {
      return ((EnumBiMap<?, V>) map).valueTypeOrObjectUnderJ2cl;
    }
    checkArgument(!map.isEmpty());