private String getDefaultMessage() {
        try {
            final Method method = UriType.class.getMethod("message");
            final Object defaultValue = method.getDefaultValue();
            return defaultValue != null ? defaultValue.toString() : null;
        } catch (final Exception e) {
            return "{org.lastaflute.validator.constraints.UriType.message}";
        }
    }

  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public T get() {
    return reference;
  }

  @Override
  public T or(T defaultValue) {
    checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
    return reference;
  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);

          <version>1.0.0+</version>
          <description>Whether to use a local copy instead (with filename that includes the base version)</description>
          <type>boolean</type>
          <defaultValue>false</defaultValue>
        </field>
      </fields>
    </class>
    <class java.clone="deep">
      <name>SnapshotVersion</name>
      <version>1.1.0+</version>

          <description>The type of layout this repository uses for locating and storing artifacts - can be "legacy" or
            "default".</description>
          <type>String</type>
          <defaultValue>default</defaultValue>
        </field>
      </fields>
      <codeSegments>
        <codeSegment>
          <version>1.0.0</version>
          <code><![CDATA[
            public boolean equals( Object obj )

}

// Comment returns the comment of current column.
func (ct ColumnType) Comment() (value string, ok bool) {
	return ct.CommentValue.String, ct.CommentValue.Valid
}

// DefaultValue returns the default value of current column.
func (ct ColumnType) DefaultValue() (value string, ok bool) {
	return ct.DefaultValueValue.String, ct.DefaultValueValue.Valid

          <version>1.1.0+</version>
          <defaultValue>self-first</defaultValue>
          <required>false</required>
          <type>String</type>
        </field>
        <field>
          <name>configuration</name>
          <version>1.2.0+</version>

     * @param name the property name
     * @param defaultValue the default value to use if property doesn't exist
     * @param appendValue the value to append to the property value
     */
    protected void addSystemProperty(final List<String> cmdList, final String name, final String defaultValue, final String appendValue) {
        final String value = System.getProperty(name);

        // v1 == 0.
        .optional(defaultValue = 0),
      Adapters.INTEGER_AS_BIG_INTEGER,
      algorithmIdentifier,
      name,
      validity,
      name,
      subjectPublicKeyInfo,
      Adapters.BIT_STRING.withTag(tag = 1L).optional(),
      Adapters.BIT_STRING.withTag(tag = 2L).optional(),
      extension.asSequenceOf().withExplicitBox(tag = 3).optional(defaultValue = listOf()),
      decompose = {

    return false;
  }

  @Override
  public T get() {
    throw new IllegalStateException("Optional.get() cannot be called on an absent value");
  }

  @Override
  public T or(T defaultValue) {
    return checkNotNull(defaultValue, "use Optional.orNull() instead of Optional.or(null)");
  }

  @SuppressWarnings("unchecked") // safe covariant cast
  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {

          <version>1.0.0</version>
          <name>editable</name>
          <description>Whether the value of this expression can be changed.</description>
          <type>boolean</type>
          <defaultValue>true</defaultValue>
        </field>
      </fields>
    </class>
  </classes>