| 1 | package com.hammurapi.extract; |
| 2 | |
| 3 | import java.util.Collections; |
| 4 | import java.util.Map; |
| 5 | import java.util.Set; |
| 6 | |
| 7 | import com.hammurapi.extract.ComparisonResult.Type; |
| 8 | |
| 9 | /** |
| 10 | * Extracts value at index. |
| 11 | * @author Pavel Vlasov. |
| 12 | * |
| 13 | * @param <T> |
| 14 | */ |
| 15 | public class IndexedExtractor<T, C> implements Extractor<T, T, C>, Mappable<T,T,C> { |
| 16 | |
| 17 | private int idx; |
| 18 | |
| 19 | public IndexedExtractor(int idx) { |
| 20 | this.idx = idx; |
| 21 | } |
| 22 | |
| 23 | public Set<Integer> parameterIndices() { |
| 24 | return Collections.singleton(idx); |
| 25 | } |
| 26 | |
| 27 | @Override |
| 28 | public int hashCode() { |
| 29 | final int prime = 31; |
| 30 | int result = 1; |
| 31 | result = prime * result + idx; |
| 32 | return result; |
| 33 | } |
| 34 | |
| 35 | @SuppressWarnings("unchecked") |
| 36 | @Override |
| 37 | public boolean equals(Object obj) { |
| 38 | if (this == obj) |
| 39 | return true; |
| 40 | if (obj == null) |
| 41 | return false; |
| 42 | if (getClass() != obj.getClass()) |
| 43 | return false; |
| 44 | IndexedExtractor other = (IndexedExtractor) obj; |
| 45 | if (idx != other.idx) |
| 46 | return false; |
| 47 | return true; |
| 48 | } |
| 49 | |
| 50 | |
| 51 | public T extract(C context, Map<C, Map<Extractor<T, ? super T, C>, ? super T>> cache, T... obj) { |
| 52 | return obj[idx]; |
| 53 | } |
| 54 | |
| 55 | public boolean isContextDependent() { |
| 56 | return false; |
| 57 | } |
| 58 | |
| 59 | @Override |
| 60 | public String toString() { |
| 61 | return "IndexedExtractor [idx=" + idx + "]"; |
| 62 | } |
| 63 | |
| 64 | @Override |
| 65 | public ComparisonResult compareTo(Extractor<T, T, C> other) { |
| 66 | if (other instanceof IndexedExtractor) { |
| 67 | int otherIdx = ((IndexedExtractor<T, C>) other).idx; |
| 68 | if (otherIdx==idx) { |
| 69 | return ComparisonResult.EQUAL_NM; |
| 70 | } |
| 71 | int[] map = new int[otherIdx+1]; |
| 72 | map[otherIdx]= idx; |
| 73 | return new ComparisonResult(Type.EQUAL, map); |
| 74 | } |
| 75 | return ComparisonResult.NOT_EQUAL_NM; |
| 76 | } |
| 77 | |
| 78 | @Override |
| 79 | public double getCost() { |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | @Override |
| 84 | public Extractor<T, T, C> map(int[] map) { |
| 85 | for (int i=0; i<map.length; ++i) { |
| 86 | if (map[i]==idx) { |
| 87 | return new IndexedExtractor<T, C>(i); |
| 88 | } |
| 89 | } |
| 90 | return null; |
| 91 | } |
| 92 | |
| 93 | public int getIndex() { |
| 94 | return idx; |
| 95 | } |
| 96 | } |