001/*
002 * Portions of this software was developed by employees of the National Institute
003 * of Standards and Technology (NIST), an agency of the Federal Government and is
004 * being made available as a public service. Pursuant to title 17 United States
005 * Code Section 105, works of NIST employees are not subject to copyright
006 * protection in the United States. This software may be subject to foreign
007 * copyright. Permission in the United States and in foreign countries, to the
008 * extent that NIST may hold copyright, to use, copy, modify, create derivative
009 * works, and distribute this software and its documentation without fee is hereby
010 * granted on a non-exclusive basis, provided that this notice and disclaimer
011 * of warranty appears in all copies.
012 *
013 * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
014 * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
015 * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
016 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
017 * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
018 * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
019 * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
020 * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
021 * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
022 * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
023 * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
024 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
025 */
026
027package gov.nist.secauto.metaschema.core.metapath.function;
028
029import java.util.Objects;
030
031public enum Occurrence {
032  /**
033   * An empty sequence.
034   */
035  ZERO("", true),
036  /**
037   * The occurrence indicator {@code "?"}.
038   */
039  ZERO_OR_ONE("?", true),
040  /**
041   * No occurrence indicator.
042   */
043  ONE("", false),
044  /**
045   * The occurrence indicator {@code "*"}.
046   */
047  ZERO_OR_MORE("*", true),
048  /**
049   * The occurrence indicator {@code "+"}.
050   */
051  ONE_OR_MORE("+", false);
052
053  private final String indicator;
054  private final boolean optional;
055
056  Occurrence(String indicator, boolean optional) {
057    Objects.requireNonNull(indicator, "indicator");
058    this.indicator = indicator;
059    this.optional = optional;
060  }
061
062  /**
063   * Get the occurrence indicator to use in the signature string for the argument.
064   *
065   * @return the occurrence indicator
066   */
067  public String getIndicator() {
068    return indicator;
069  }
070
071  /**
072   * Determine if providing a value is optional based on the occurrence.
073   *
074   * @return {@code true} if providing a value is optional or {@code false} if
075   *         required
076   */
077  public boolean isOptional() {
078    return optional;
079  }
080}