001/*
002 * Copyright (C) 2022 - 2023, the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *    http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package io.github.ascopes.jct.filemanagers.config;
017
018import io.github.ascopes.jct.filemanagers.JctFileManager;
019import java.util.Deque;
020import java.util.LinkedList;
021import java.util.List;
022import org.apiguardian.api.API;
023import org.apiguardian.api.API.Status;
024import org.slf4j.Logger;
025import org.slf4j.LoggerFactory;
026
027/**
028 * A chain of configurers to apply to a file manager.
029 *
030 * @author Ashley Scopes
031 * @since 0.0.1 (0.0.1-M7)
032 */
033@API(since = "0.0.1", status = Status.STABLE)
034public final class JctFileManagerConfigurerChain {
035
036  private static final Logger LOGGER = LoggerFactory.getLogger(JctFileManagerConfigurerChain.class);
037
038  private final Deque<JctFileManagerConfigurer> configurers;
039
040  /**
041   * Initialise this chain.
042   */
043  public JctFileManagerConfigurerChain() {
044    configurers = new LinkedList<>();
045  }
046
047  /**
048   * Add a configurer to the start of the chain.
049   *
050   * @param configurer the configurer to add.
051   * @return this chain for further calls.
052   */
053  public JctFileManagerConfigurerChain addFirst(JctFileManagerConfigurer configurer) {
054    configurers.addFirst(configurer);
055    return this;
056  }
057
058  /**
059   * Add a configurer to the end of the chain.
060   *
061   * @param configurer the configurer to add.
062   * @return this chain for further calls.
063   */
064  public JctFileManagerConfigurerChain addLast(JctFileManagerConfigurer configurer) {
065    configurers.addLast(configurer);
066    return this;
067  }
068
069  /**
070   * Get an immutable copy of the list of configurers.
071   *
072   * @return the list of configurers.
073   */
074  public List<JctFileManagerConfigurer> list() {
075    return List.copyOf(configurers);
076  }
077
078  /**
079   * Apply each configurer to the given file manager in order.
080   *
081   * @param fileManager the file manager to configure.
082   * @return the configured file manager to use. This may or may not be the same object as the input
083   *     parameter, depending on how the configurers manipulate the input object.
084   */
085  public JctFileManager configure(JctFileManager fileManager) {
086    for (var configurer : configurers) {
087      if (configurer.isEnabled()) {
088        LOGGER.trace("Applying {} to file manager", configurer);
089        fileManager = configurer.configure(fileManager);
090      } else {
091        LOGGER.trace("Skipping {}", configurer);
092      }
093    }
094
095    return fileManager;
096  }
097}