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
31 import edu.umd.cs.findbugs.annotations.NonNull;
32 import edu.umd.cs.findbugs.annotations.Nullable;
33
34 abstract class AbstractBasicArithmeticExpression
35 extends AbstractArithmeticExpression<IAnyAtomicItem> {
36
37 /**
38 * An expression that represents a basic arithmetic operation on two values.
39 *
40 * @param left
41 * the first item
42 * @param right
43 * the second item
44 */
45 public AbstractBasicArithmeticExpression(@NonNull IExpression left, @NonNull IExpression right) {
46 super(left, right, IAnyAtomicItem.class);
47 }
48
49 @Override
50 public Class<IAnyAtomicItem> getBaseResultType() {
51 return IAnyAtomicItem.class;
52 }
53
54 @Override
55 public ISequence<? extends IAnyAtomicItem> accept(DynamicContext dynamicContext, ISequence<?> focus) {
56 IAnyAtomicItem leftItem = getFirstDataItem(getLeft().accept(dynamicContext, focus), true);
57 IAnyAtomicItem rightItem = getFirstDataItem(getRight().accept(dynamicContext, focus), true);
58
59 return resultOrEmpty(leftItem, rightItem);
60 }
61
62 /**
63 * Setup the operation on two atomic items.
64 *
65 * @param leftItem
66 * the first item
67 * @param rightItem
68 * the second item
69 * @return the result of the operation or an empty {@link ISequence} if either
70 * item is {@code null}
71 */
72 @NonNull
73 protected ISequence<? extends IAnyAtomicItem> resultOrEmpty(
74 @Nullable IAnyAtomicItem leftItem,
75 @Nullable IAnyAtomicItem rightItem) {
76 ISequence<? extends IAnyAtomicItem> retval;
77 if (leftItem == null || rightItem == null) {
78 retval = ISequence.empty();
79 } else {
80 IAnyAtomicItem result = operation(leftItem, rightItem);
81 retval = ISequence.of(result);
82 }
83 return retval;
84 }
85
86 /**
87 * Performs the arithmetic operation using the two provided values.
88 *
89 * @param left
90 * the first item
91 * @param right
92 * the second item
93 * @return the result of the operation
94 */
95 @NonNull
96 protected abstract IAnyAtomicItem operation(@NonNull IAnyAtomicItem left, @NonNull IAnyAtomicItem right);
97 }