| 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 | } |