1 | package com.hammurapi.extract; |
2 | |
3 | import java.util.Map; |
4 | import java.util.Set; |
5 | |
6 | /** |
7 | * Utility class. |
8 | * @author Pavel Vlasov |
9 | * |
10 | */ |
11 | public class ExtractorUtil { |
12 | |
13 | private ExtractorUtil() { |
14 | // TODO Auto-generated constructor stub |
15 | } |
16 | |
17 | /** |
18 | * Wraps extractor into predicate, if given extractor is not already a predicate. |
19 | * @param <T> |
20 | * @param <C> |
21 | * @param extractor |
22 | * @return |
23 | */ |
24 | public static <T,C> Predicate<T,C> wrap(final Extractor<T,Boolean,C> extractor) { |
25 | if (extractor instanceof Predicate) { |
26 | return (Predicate<T,C>) extractor; |
27 | } |
28 | |
29 | return new Predicate<T,C>() { |
30 | |
31 | @Override |
32 | public Boolean extract( |
33 | C context, |
34 | Map<C, Map<Extractor<T, ? super Boolean, C>, ? super Boolean>> cache, |
35 | T... obj) { |
36 | return extractor.extract(context, cache, obj); |
37 | } |
38 | |
39 | @Override |
40 | public Set<Integer> parameterIndices() { |
41 | return extractor.parameterIndices(); |
42 | } |
43 | |
44 | @Override |
45 | public boolean isContextDependent() { |
46 | return extractor.isContextDependent(); |
47 | } |
48 | |
49 | @Override |
50 | public ComparisonResult compareTo(Extractor<T, Boolean, C> other) { |
51 | return extractor.compareTo(other); |
52 | } |
53 | |
54 | @Override |
55 | public double getCost() { |
56 | return extractor.getCost(); |
57 | } |
58 | |
59 | }; |
60 | |
61 | } |
62 | |
63 | /** |
64 | * |
65 | * @param <T> |
66 | * @param <V> |
67 | * @param <C> |
68 | * @param source Source extractor. |
69 | * @return Instance of mappable if extractor is mappable or its parameter indices is empty. Null otherwise. |
70 | */ |
71 | public static <T,V,C> Mappable<T,V,C> toMappable(final Extractor<T,V,C> source) { |
72 | if (source==null) { |
73 | return null; |
74 | } |
75 | if (source instanceof Mappable) { |
76 | return (Mappable<T,V,C>) source; |
77 | } |
78 | if (source.parameterIndices().isEmpty()) { |
79 | return new Mappable<T,V,C>() { |
80 | |
81 | @Override |
82 | public Extractor<T, V, C> map(int[] map) { |
83 | return source; |
84 | } |
85 | |
86 | }; |
87 | } |
88 | return null; |
89 | } |
90 | |
91 | } |