1 /*
2 * Portions of this software was developed by employees of the National Institute
3 * of Standards and Technology (NIST), an agency of the Federal Government and is
4 * being made available as a public service. Pursuant to title 17 United States
5 * Code Section 105, works of NIST employees are not subject to copyright
6 * protection in the United States. This software may be subject to foreign
7 * copyright. Permission in the United States and in foreign countries, to the
8 * extent that NIST may hold copyright, to use, copy, modify, create derivative
9 * works, and distribute this software and its documentation without fee is hereby
10 * granted on a non-exclusive basis, provided that this notice and disclaimer
11 * of warranty appears in all copies.
12 *
13 * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
14 * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
15 * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
17 * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
18 * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE. IN NO EVENT
19 * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
20 * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
21 * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
22 * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
23 * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
24 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
25 */
26
27 package gov.nist.secauto.metaschema.core.metapath;
28
29 import gov.nist.secauto.metaschema.core.metapath.item.IItem;
30 import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
31 import gov.nist.secauto.metaschema.core.util.ObjectUtils;
32
33 import java.util.List;
34
35 import edu.umd.cs.findbugs.annotations.NonNull;
36
37 /**
38 * An immutable expression that combines the evaluation of a sub-expression,
39 * with the evaluation of a series of predicate expressions that filter the
40 * result of the evaluation.
41 */
42 class Step implements IExpression { // NOPMD - intentional
43
44 @NonNull
45 private final Axis axisExpression;
46 @NonNull
47 private final IExpression stepExpression;
48 @NonNull
49 private final Class<? extends IItem> staticResultType;
50
51 /**
52 * Construct a new stepExpression expression.
53 *
54 * @param axis
55 * the axis to evaluate against
56 * @param step
57 * the sub-expression to evaluate before filtering with the predicates
58 */
59 @SuppressWarnings("null")
60 protected Step(@NonNull Axis axis, @NonNull IExpression step) {
61 this.axisExpression = axis;
62 this.stepExpression = step;
63 this.staticResultType = ExpressionUtils.analyzeStaticResultType(IItem.class, List.of(step));
64 }
65
66 @NonNull
67 public Axis getAxis() {
68 return axisExpression;
69 }
70
71 /**
72 * Get the stepExpression's sub-expression.
73 *
74 * @return the sub-expression
75 */
76 @NonNull
77 public IExpression getStep() {
78 return stepExpression;
79 }
80
81 @Override
82 public Class<? extends IItem> getStaticResultType() {
83 return staticResultType;
84 }
85
86 @Override
87 public List<? extends IExpression> getChildren() {
88 return ObjectUtils.notNull(List.of(getAxis(), getStep()));
89 }
90
91 @Override
92 public <RESULT, CONTEXT> RESULT accept(IExpressionVisitor<RESULT, CONTEXT> visitor, CONTEXT context) {
93 return visitor.visitStep(this, context);
94 }
95
96 @Override
97 public ISequence<?> accept(DynamicContext dynamicContext, ISequence<?> focus) {
98
99 ISequence<? extends INodeItem> axisResult = getAxis().accept(dynamicContext, focus);
100 return getStep().accept(dynamicContext, axisResult);
101 }
102
103 @SuppressWarnings("null")
104 @Override
105 public String toASTString() {
106 return String.format("%s[axis=%s]", getClass().getName(), getAxis().name());
107 }
108 }