*/
  @Synchronized
  @Throws(IOException::class)
  operator fun get(key: String): Snapshot? {
    initialize()

    checkNotClosed()
    validateKey(key)
    val entry = lruEntries[key] ?: return null
    val snapshot = entry.snapshot() ?: return null

    redundantOpCount++
    journalWriter!!.writeUtf8(READ)
      .writeByte(' '.code)

		}
	}

internalAuth:
	ui, ok := globalIAMSys.GetUser(context.Background(), user)
	if !ok {
		return nil, errNoSuchUser
	}

	if caPublicKey != nil && pass == nil {
		err := validateKey(c, key)
		if err != nil {
			return nil, errAuthentication
		}
	} else {
		// Temporary credentials are not allowed.
		if ui.Credentials.IsTemp() {
			return nil, errAuthentication
		}

    filesystem.setFaultyDelete(cacheDir, false)
    val snapshot = cache["k1"]
    assertThat(snapshot).isNull()
  }

  @ParameterizedTest
  @ArgumentsSource(FileSystemParamProvider::class)
  fun validateKey(parameters: Pair<FileSystem, Boolean>) {
    setUp(parameters.first, parameters.second)
    var key = ""
    assertFailsWith<IllegalArgumentException> {
      key = "has_space "
      cache.edit(key)

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = CronExpressionValidator.class)
public @interface CronExpression {

    String message() default "{org.lastaflute.validator.constraints.CronExpression.message}";

    Class<?>[] groups() default {};

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = UriTypeValidator.class)
public @interface UriType {

    ProtocolType protocolType();

    String message() default "{org.lastaflute.validator.constraints.UriType.message}";

    Class<?>[] groups() default {};

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented
@Constraint(validatedBy = CustomSizeValidator.class)
public @interface CustomSize {

    String message() default "{jakarta.validation.constraints.Size.message}";

    Class<?>[] groups() default {};