}
  }

  /**
   * Precondition tester for {@code Iterator.remove()} that throws an exception with a consistent
   * error message.
   */
  static void checkRemove(boolean canRemove) {
    checkState(canRemove, "no calls to next() since the last call to remove()");
  }

  private CollectPreconditions() {}

      entryIndex = backingMap.nextIndex(entryIndex);
      return result;
    }

    @Override
    public void remove() {
      checkForConcurrentModification();
      CollectPreconditions.checkRemove(toRemove != -1);
      size -= backingMap.removeEntry(toRemove);
      entryIndex = backingMap.nextIndexAfterRemove(entryIndex, toRemove);
      toRemove = -1;
      expectedModCount = backingMap.modCount;
    }

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.checkRemove;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Function;
import com.google.common.base.Optional;

          remaining--;
          return result;
        }

        @Override
        public void remove() {
          checkForComodification();
          CollectPreconditions.checkRemove(indexToRemove != ABSENT);
          biMap.removeEntry(indexToRemove);
          if (index == biMap.size) {
            index = indexToRemove;
          }
          indexToRemove = ABSENT;

 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.base.Predicates.equalTo;
import static com.google.common.collect.CollectPreconditions.checkRemove;
import static com.google.common.collect.Iterators.advance;
import static com.google.common.collect.Iterators.all;
import static com.google.common.collect.Iterators.any;