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;
028
029import gov.nist.secauto.metaschema.core.metapath.antlr.metapath10Lexer;
030import gov.nist.secauto.metaschema.core.metapath.item.ItemUtils;
031import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
032import gov.nist.secauto.metaschema.core.util.CollectionUtil;
033import gov.nist.secauto.metaschema.core.util.ObjectUtils;
034
035import java.util.List;
036import java.util.function.Function;
037import java.util.stream.Stream;
038
039import edu.umd.cs.findbugs.annotations.NonNull;
040
041@SuppressWarnings("PMD.ShortClassName") // intentional
042public enum Axis implements IExpression {
043  SELF(metapath10Lexer.KW_SELF, focus -> Stream.of(focus)),
044  PARENT(metapath10Lexer.KW_PARENT, focus -> Stream.ofNullable(focus.getParentNodeItem())),
045  ANCESTOR(metapath10Lexer.KW_ANCESTOR, INodeItem::ancestor),
046  ANCESTOR_OR_SELF(metapath10Lexer.KW_ANCESTOR_OR_SELF, INodeItem::ancestorOrSelf),
047  CHILDREN(metapath10Lexer.KW_CHILD, INodeItem::modelItems),
048  DESCENDANT(metapath10Lexer.KW_DESCENDANT, INodeItem::descendant),
049  DESCENDANT_OR_SELF(metapath10Lexer.KW_DESCENDANT_OR_SELF, INodeItem::descendantOrSelf);
050
051  private final int keywordIndex;
052  @NonNull
053  private final Function<INodeItem, Stream<? extends INodeItem>> action;
054
055  Axis(int keywordIndex, @NonNull Function<INodeItem, Stream<? extends INodeItem>> action) {
056    this.keywordIndex = keywordIndex;
057    this.action = action;
058  }
059
060  /**
061   * The ANTLR keyword for this axis type.
062   *
063   * @return the keyword
064   */
065  public int getKeywordIndex() {
066    return keywordIndex;
067  }
068
069  /**
070   * Execute the axis operation on the provided {@code focus}.
071   *
072   * @param focus
073   *          the node to operate on
074   * @return the result of the axis operation
075   */
076  @NonNull
077  public Stream<? extends INodeItem> execute(@NonNull INodeItem focus) {
078    return ObjectUtils.notNull(action.apply(focus));
079  }
080
081  @Override
082  public List<? extends IExpression> getChildren() {
083    return CollectionUtil.emptyList();
084  }
085
086  @Override
087  public Class<INodeItem> getBaseResultType() {
088    return INodeItem.class;
089  }
090
091  @Override
092  public Class<INodeItem> getStaticResultType() {
093    return getBaseResultType();
094  }
095
096  @Override
097  public <RESULT, CONTEXT> RESULT accept(IExpressionVisitor<RESULT, CONTEXT> visitor, CONTEXT context) {
098    return visitor.visitAxis(this, context);
099  }
100
101  @Override
102  public ISequence<? extends INodeItem> accept(
103      DynamicContext dynamicContext,
104      ISequence<?> outerFocus) {
105    ISequence<? extends INodeItem> retval;
106    if (outerFocus.isEmpty()) {
107      retval = ISequence.empty();
108    } else {
109      retval = ISequence.of(outerFocus.asStream()
110          .map(item -> ItemUtils.checkItemIsNodeItemForStep(item))
111          .flatMap(item -> {
112            assert item != null;
113            return execute(item);
114          }).distinct());
115    }
116    return retval;
117  }
118}