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.atomic.IAnyAtomicItem;
30 import gov.nist.secauto.metaschema.core.metapath.item.atomic.IBooleanItem;
31
32 import edu.umd.cs.findbugs.annotations.NonNull;
33 import edu.umd.cs.findbugs.annotations.Nullable;
34
35 class ValueComparison
36 extends AbstractComparison {
37
38 /**
39 * Create a new value comparison expression.
40 *
41 * @param left
42 * the expression to compare against
43 * @param operator
44 * the comparison operator
45 * @param right
46 * the expression to compare with
47 */
48 protected ValueComparison(@NonNull IExpression left, @NonNull Operator operator, @NonNull IExpression right) {
49 super(left, operator, right);
50 }
51
52 @Override
53 public <RESULT, CONTEXT> RESULT accept(IExpressionVisitor<RESULT, CONTEXT> visitor, CONTEXT context) {
54 return visitor.visitValueComparison(this, context);
55 }
56
57 @Override
58 public ISequence<? extends IBooleanItem> accept(DynamicContext dynamicContext, ISequence<?> focus) {
59 IAnyAtomicItem left = getFirstDataItem(getLeft().accept(dynamicContext, focus), false);
60 IAnyAtomicItem right = getFirstDataItem(getRight().accept(dynamicContext, focus), false);
61
62 return resultOrEmpty(left, right);
63 }
64
65 /**
66 * Compare the two atomic items.
67 *
68 * @param leftItem
69 * the first item to compare
70 * @param rightItem
71 * the second item to compare
72 * @return a or an empty {@link ISequence} if either item is {@code null}
73 */
74 @NonNull
75 protected ISequence<? extends IBooleanItem> resultOrEmpty(@Nullable IAnyAtomicItem leftItem,
76 @Nullable IAnyAtomicItem rightItem) {
77 ISequence<? extends IBooleanItem> retval;
78 if (leftItem == null || rightItem == null) {
79 retval = ISequence.empty();
80 } else {
81 IBooleanItem result = valueCompairison(leftItem, getOperator(), rightItem);
82 retval = ISequence.of(result);
83 }
84 return retval;
85 }
86
87 /**
88 * Compare the two items using the provided {@code operator}.
89 *
90 * @param leftItem
91 * the first item to compare
92 * @param operator
93 * the comparison operator
94 * @param rightItem
95 * the second item to compare
96 * @return the result of the comparison
97 */
98 @NonNull
99 protected IBooleanItem valueCompairison(@NonNull IAnyAtomicItem leftItem, @NonNull Operator operator,
100 @NonNull IAnyAtomicItem rightItem) {
101 return compare(leftItem, operator, rightItem);
102 }
103 }