001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*-
002 *
003 * Copyright © 2020 microBean™.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
014 * implied.  See the License for the specific language governing
015 * permissions and limitations under the License.
016 */
017package org.microbean.settings.converter;
018
019import java.util.Objects;
020import java.util.Optional;
021
022import javax.enterprise.inject.Vetoed;
023
024import javax.inject.Inject;
025
026import org.microbean.settings.Converter;
027import org.microbean.settings.Value;
028
029@Vetoed
030public class OptionalConverter<T> implements Converter<Optional<T>> {
031
032  private static final long serialVersionUID = 1L;
033
034  private final Converter<? extends T> baseConverter;
035
036  public OptionalConverter(final Converter<? extends T> baseConverter) {
037    super();
038    this.baseConverter = Objects.requireNonNull(baseConverter);
039  }
040
041  @Override
042  public Optional<T> convert(final Value value) {
043    final Optional<T> returnValue;
044    if (value == null) {
045      returnValue = Optional.empty();
046    } else {
047      returnValue = Optional.ofNullable(this.baseConverter.convert(value));
048    }
049    return returnValue;
050  }
051
052}