org.opentcs.configuration.ConfigurationEntry Maven / Gradle / Ivy

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// SPDX-FileCopyrightText: The openTCS Authors
// SPDX-License-Identifier: MIT
package org.opentcs.configuration;

import static java.lang.annotation.ElementType.METHOD;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Marks an interface's method that provides a configuration value.
 */
@Target({METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ConfigurationEntry {

  /**
   * Returns a description for the data type of this configuration key's values.
   *
   * @return A description for the data type of this configuration key's values.
   */
  String type();

  /**
   * Returns a list of paragraphs describing what the key/value configures.
   *
   * @return A list of paragraphs describing what the key/value configures.
   */
  String[] description();

  /**
   * Indicates when changes to the configuration entry's value are applied.
   *
   * @return A value indicating when changes to the configuration entry's value are applied.
   */
  ChangesApplied changesApplied() default ChangesApplied.UNSPECIFIED;

  /**
   * Returns the optional ordering key that this entry belongs to (for grouping/sorting of entries).
   *
   * @return The optional ordering key that this entry belongs to (for grouping/sorting of entries).
   */
  String orderKey() default "";

  /**
   * Indicates when changes to the configuration entry's value are applied.
   */
  enum ChangesApplied {
    /**
     * When a configuration change is applied is not explicitly specified.
     */
    UNSPECIFIED,
    /**
     * Changes to the configuration value are picked up when the application is (re)started.
     */
    ON_APPLICATION_START,
    /**
     * Changes to the configuration value are picked up when/after a plant model is loaded.
     */
    ON_NEW_PLANT_MODEL,
    /**
     * Changes to the configuration value are picked up during runtime instantly, without
     * requiring an explicit trigger.
     */
    INSTANTLY
  }
}