return (row == null) ? null : safeGet(row, columnKey);
  }

  @Override
  public boolean isEmpty() {
    return size() == 0;
  }

  @Override
  public void clear() {
    Iterators.clear(cellSet().iterator());
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
    Map<C, V> row = safeGet(rowMap(), rowKey);

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class CollectionClearTester<E> extends AbstractCollectionTester<E> {
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    collection.clear();
    assertTrue("After clear(), a collection should be empty.", collection.isEmpty());
    assertEquals(0, collection.size());

	// Clear
	if err := DB.Model(&user2).Association("Company").Clear(); err != nil {
		t.Errorf("Error happened when clear Company, got %v", err)
	}

	if err := DB.Model(&user2).Association("Manager").Clear(); err != nil {
		t.Errorf("Error happened when clear Manager, got %v", err)
	}

	AssertAssociationCount(t, user2, "Company", 0, "after clear")

import java.util.Map;
import java.util.Set;

import org.codelibs.fess.unit.UnitFessTestCase;

public class DocMapTest extends UnitFessTestCase {
    public void test_DocList() {
        Map<String, Object> value = new LinkedHashMap<>();
        DocMap docMap = new DocMap(value);
        assertTrue(docMap.isEmpty());
        value.clear();

        List<String> keys = Arrays.asList("test_2", "test_0", "lang", "test_1");

    };
  }

  @WeakOuter
  private final class Values extends AbstractCollection<V> {
    @Override
    public Iterator<V> iterator() {
      return valuesIterator();
    }

    @Override
    public boolean contains(@Nullable Object o) {
      return containsValue(o);
    }

    @Override
    public void clear() {
      AbstractTable.this.clear();
    }

    @Override

assignees: ''

---

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

**Describe the solution you'd like**
A clear and concise description of what you want to happen.

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**

      if (record != null) {
        list.add(record);
      }
    }
  }

  @Override
  public void flush() {}

  @Override
  public void close() {}

  public void clear() {
    synchronized (lock) {
      list.clear();
    }
  }

  /** Returns a snapshot of the logged records. */
  /*
   * TODO(cpovirk): consider higher-level APIs here (say, assertNoRecordsLogged(),

  private static final Ordering<List<Class<?>>> ORDERING_BY_CONSTRUCTOR_PARAMETER_LIST =
      Ordering.natural()
          .onResultOf((List<Class<?>> params) -> params.contains(String.class))
          .compound(
              Ordering.natural()
                  .onResultOf((List<Class<?>> params) -> params.contains(Throwable.class)))
          .reverse();

	}

	// Clear
	DB.Model(&blog2).Association("LocaleTags").Clear()
	if DB.Model(&blog).Association("LocaleTags").Count() != 3 {
		t.Fatalf("ZH Blog's tags should not be cleared when clear EN Blog's tags")
	}

	if DB.Model(&blog2).Association("LocaleTags").Count() != 0 {
		t.Fatalf("EN Blog's tags should be cleared when clear EN Blog's tags")
	}

    }
    return null;
  }

  /**
   * A sensible definition of {@link #clear} in terms of the {@code iterator} method of {@link
   * #entrySet}. In many cases, you may wish to override {@link #clear} to forward to this
   * implementation.
   *
   * @since 7.0
   */
  protected void standardClear() {
    Iterators.clear(entrySet().iterator());
  }

  /**