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 gov.nist.secauto.metaschema.core.metapath.item.IItem;
030
031import edu.umd.cs.findbugs.annotations.NonNull;
032
033public interface ISequenceType {
034  @NonNull
035  ISequenceType EMPTY = new ISequenceType() {
036    @Override
037    public boolean isEmpty() {
038      return true;
039    }
040
041    @Override
042    public Class<? extends IItem> getType() {
043      return null;
044    }
045
046    @Override
047    public Occurrence getOccurrence() {
048      return null;
049    }
050
051    @Override
052    public String toSignature() {
053      return "()";
054    }
055  };
056
057  /**
058   * Determine if the sequence is empty (if it holds any data) or not.
059   *
060   * @return {@code true} if the sequence is empty or {@code false} otherwise
061   */
062  boolean isEmpty();
063
064  /**
065   * Get the type of the sequence.
066   *
067   * @return the type of the sequence or {@code null} if the sequence is empty
068   */
069  Class<? extends IItem> getType();
070
071  /**
072   * Get the occurrence of the sequence.
073   *
074   * @return the occurrence of the sequence or {@code null} if the sequence is
075   *         empty
076   */
077  Occurrence getOccurrence();
078
079  /**
080   * Get the signature of the function as a string.
081   *
082   * @return the signature
083   */
084  String toSignature();
085}