git.basschouten.com Git - openhab-addons.git/blob

   1 /**
   2  * Copyright (c) 2010-2023 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.mielecloud.internal.webservice.language;
  14
  15 import java.util.Optional;
  16
  17 import org.eclipse.jdt.annotation.NonNullByDefault;
  18 import org.eclipse.jdt.annotation.Nullable;
  19
  20 /**
  21  * {@link LanguageProvider} combining two {@link LanguageProvider}s, a prioritized and a fallback provider.
  22  *
  23  * @author Björn Lange - Initial contribution
  24  */
  25 @NonNullByDefault
  26 public class CombiningLanguageProvider implements LanguageProvider {
  27     private @Nullable LanguageProvider prioritizedLanguageProvider;
  28     private @Nullable LanguageProvider fallbackLanguageProvider;
  29
  30     /**
  31      * Creates a new instance.
  32      *
  33      * @param prioritizedLanguageProvider Primary {@link LanguageProvider} to use. May be {@code null}, in that case the
  34      *            {@code fallbackLanguageProvider} will be used.
  35      * @param fallbackLanguageProvider {@link LanguageProvider} to fall back to if the
  36      *            {@code prioritizedLanguageProvider} is {@code null} or provides no language. May be
  37      *            {@code null}, in case the fallback is used and returns no language then no language will be returned.
  38      */
  39     public CombiningLanguageProvider(@Nullable LanguageProvider prioritizedLanguageProvider,
  40             @Nullable LanguageProvider fallbackLanguageProvider) {
  41         this.prioritizedLanguageProvider = prioritizedLanguageProvider;
  42         this.fallbackLanguageProvider = fallbackLanguageProvider;
  43     }
  44
  45     public void setPrioritizedLanguageProvider(LanguageProvider prioritizedLanguageProvider) {
  46         this.prioritizedLanguageProvider = prioritizedLanguageProvider;
  47     }
  48
  49     public void unsetPrioritizedLanguageProvider() {
  50         this.prioritizedLanguageProvider = null;
  51     }
  52
  53     public void setFallbackLanguageProvider(LanguageProvider fallbackLanguageProvider) {
  54         this.fallbackLanguageProvider = fallbackLanguageProvider;
  55     }
  56
  57     public void unsetFallbackLanguageProvider() {
  58         this.fallbackLanguageProvider = null;
  59     }
  60
  61     @Override
  62     public Optional<String> getLanguage() {
  63         Optional<String> prioritizedLanguage = Optional.ofNullable(prioritizedLanguageProvider)
  64                 .flatMap(LanguageProvider::getLanguage);
  65         if (prioritizedLanguage.isPresent()) {
  66             return prioritizedLanguage;
  67         } else {
  68             return Optional.ofNullable(fallbackLanguageProvider).flatMap(LanguageProvider::getLanguage);
  69         }
  70     }
  71 }