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
31 import java.util.List;
32
33 import edu.umd.cs.findbugs.annotations.NonNull;
34
35 abstract class AbstractFilterExpression
36 extends AbstractBinaryExpression<IExpression, IExpression> {
37
38 @NonNull
39 private final Class<? extends IItem> staticResultType;
40
41 /**
42 * Construct a new filter expression.
43 *
44 * @param left
45 * an expression indicating the items to filter
46 * @param right
47 * an expression indicating the items to use as the filter
48 */
49 @SuppressWarnings("null")
50 public AbstractFilterExpression(@NonNull IExpression left, @NonNull IExpression right) {
51 super(left, right);
52 this.staticResultType = ExpressionUtils.analyzeStaticResultType(IItem.class, List.of(left, right));
53 }
54
55 @Override
56 public Class<? extends IItem> getStaticResultType() {
57 return staticResultType;
58 }
59
60 @Override
61 public ISequence<? extends IItem> accept(
62 @NonNull DynamicContext dynamicContext,
63 @NonNull ISequence<?> focus) {
64
65 ISequence<?> left = getLeft().accept(dynamicContext, focus);
66 ISequence<?> right = getRight().accept(dynamicContext, focus);
67 List<? extends IItem> rightList = right.asList();
68
69 return applyFilterTo(left, rightList);
70 }
71
72 /**
73 * A callback used to apply the filter to the result of evaluating the left
74 * expression.
75 *
76 * @param result
77 * the set of items to filter
78 * @param items
79 * a list of items to filter with
80 * @return the filtered result set
81 */
82 @NonNull
83 protected abstract ISequence<?> applyFilterTo(
84 @NonNull ISequence<?> result,
85 @NonNull List<? extends IItem> items);
86 }