| 1 | package com.hammurapi.extract; |
| 2 | |
| 3 | import java.lang.reflect.Array; |
| 4 | import java.util.Arrays; |
| 5 | import java.util.HashSet; |
| 6 | import java.util.Map; |
| 7 | import java.util.Set; |
| 8 | import java.util.TreeSet; |
| 9 | |
| 10 | /** |
| 11 | * Extractor which maps arguments to the target extractor. |
| 12 | * @author Pavel Vlasov |
| 13 | * |
| 14 | * @param <T> |
| 15 | * @param <V> |
| 16 | * @param <C> |
| 17 | */ |
| 18 | public class MappedExtractor<T, V, C> implements FacadeExtractor<T, V, C>, Mappable<T,V,C> { |
| 19 | |
| 20 | private Extractor<T, V, C> target; |
| 21 | private int[] map; |
| 22 | private TreeSet<Integer> parameterIndices; |
| 23 | |
| 24 | /** |
| 25 | * @param target Target extractor |
| 26 | * @param map Index map, e.g. if it is {5, 3} then the first argument |
| 27 | * of this extractor becomes the sixth argument of the target extractor |
| 28 | * and the second argument of this extractor becomes the 4th argument |
| 29 | * of the target extractor. |
| 30 | */ |
| 31 | protected MappedExtractor(Extractor<T, V, C> target, int[] map) { |
| 32 | super(); |
| 33 | this.target = target; |
| 34 | this.map = map; |
| 35 | |
| 36 | parameterIndices = new TreeSet<Integer>(); |
| 37 | |
| 38 | Set<Integer> tpIdx = target.parameterIndices(); |
| 39 | for (int i=0; i<map.length; ++i) { |
| 40 | if (tpIdx.contains(map[i])) { |
| 41 | parameterIndices.add(i); |
| 42 | } |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | @Override |
| 47 | public V extract(C context, Map<C, Map<Extractor<T, ? super V, C>, ? super V>> cache, T... obj) { |
| 48 | int maxTargetIndex = -1; |
| 49 | for (Integer tIdx: target.parameterIndices()) { |
| 50 | if (tIdx>maxTargetIndex) { |
| 51 | maxTargetIndex=tIdx; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | @SuppressWarnings("unchecked") |
| 56 | T[] tObj = (T[]) Array.newInstance(obj.getClass().getComponentType(), maxTargetIndex+1); |
| 57 | for (int i=0; i<map.length; ++i) { |
| 58 | if (parameterIndices.contains(i)) { |
| 59 | tObj[map[i]] = obj[i]; |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | return target.extract(context, cache, tObj); |
| 64 | } |
| 65 | |
| 66 | @Override |
| 67 | public Set<Integer> parameterIndices() { |
| 68 | return parameterIndices; |
| 69 | } |
| 70 | |
| 71 | @Override |
| 72 | public boolean isContextDependent() { |
| 73 | return target.isContextDependent(); |
| 74 | } |
| 75 | |
| 76 | @Override |
| 77 | public ComparisonResult compareTo(Extractor<T, V, C> other) { |
| 78 | ComparisonResult tcr = target.compareTo(other); |
| 79 | if (tcr==null) { |
| 80 | return null; |
| 81 | } |
| 82 | if (tcr.isOneToOneMapping()) { |
| 83 | // Inverse mapping. |
| 84 | int dim = -1; |
| 85 | for (int i=0; i<map.length; ++i) { |
| 86 | if (parameterIndices.contains(i) && map[i]>dim) { |
| 87 | dim = map[i]; |
| 88 | } |
| 89 | } |
| 90 | int[] rmap = new int[dim+1]; |
| 91 | Arrays.fill(rmap, -1); |
| 92 | for (int i=0; i<map.length; ++i) { |
| 93 | if (parameterIndices.contains(i)) { |
| 94 | rmap[map[i]] = i; |
| 95 | } |
| 96 | } |
| 97 | return new ComparisonResult(tcr.getType(), rmap); |
| 98 | } |
| 99 | |
| 100 | int[] tcrim = tcr.getIndexMap(); |
| 101 | int[] cmap = new int[map.length]; |
| 102 | Arrays.fill(cmap, -1); |
| 103 | for (int i=0; i<map.length; ++i) { |
| 104 | if (parameterIndices.contains(i)) { |
| 105 | if (tcrim.length>map[i]) { |
| 106 | cmap[i] = tcrim[map[i]]; |
| 107 | } else { |
| 108 | return null; |
| 109 | } |
| 110 | } |
| 111 | } |
| 112 | return new ComparisonResult(tcr.getType(), cmap); |
| 113 | } |
| 114 | |
| 115 | @Override |
| 116 | public String toString() { |
| 117 | return "MappedExtractor [target=" + target + ", map=" |
| 118 | + Arrays.toString(map) + "]"; |
| 119 | } |
| 120 | |
| 121 | @Override |
| 122 | public double getCost() { |
| 123 | return target.getCost(); |
| 124 | } |
| 125 | |
| 126 | |
| 127 | public static <T,V,C> Extractor<T,V,C> mapExtractor(Extractor<T,V,C> target, int[] map) { |
| 128 | if (ComparisonResult.isOneToOneMapping(map)) { |
| 129 | return target; |
| 130 | } |
| 131 | |
| 132 | // Target is not index-dependent (e.g. constant). |
| 133 | if (target.parameterIndices().isEmpty()) { |
| 134 | return target; |
| 135 | } |
| 136 | if (target instanceof Mappable) { |
| 137 | @SuppressWarnings("unchecked") |
| 138 | Extractor<T, V, C> ret = ((Mappable<T,V,C>) target).map(map); |
| 139 | if (ret!=null) { |
| 140 | return ret; |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | return new MappedExtractor<T, V, C>(target, map); |
| 145 | } |
| 146 | |
| 147 | @SuppressWarnings("unchecked") |
| 148 | @Override |
| 149 | public Extractor<T, V, C> map(int[] map) { |
| 150 | if (ComparisonResult.isOneToOneMapping(map)) { |
| 151 | return this; |
| 152 | } |
| 153 | |
| 154 | int[] newMap = new int[map.length]; |
| 155 | Arrays.fill(newMap, -1); |
| 156 | |
| 157 | Set<Integer> pi = new HashSet<Integer>(parameterIndices); |
| 158 | |
| 159 | for (int i=0; i<newMap.length; ++i) { |
| 160 | if (map[i]!=-1) { |
| 161 | if (pi.remove(map[i])) { |
| 162 | newMap[i]=this.map[map[i]]; |
| 163 | } |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | if (!pi.isEmpty()) { // Not all indexes were mapped. |
| 168 | return null; |
| 169 | } |
| 170 | |
| 171 | if (ComparisonResult.isOneToOneMapping(newMap)) { |
| 172 | return target; |
| 173 | } |
| 174 | |
| 175 | if (this instanceof MappedPredicate) { |
| 176 | return (Extractor<T, V, C>) new MappedPredicate<T, C>((Predicate<T, C>) target, newMap); |
| 177 | } |
| 178 | return new MappedExtractor<T, V, C>(target, newMap); |
| 179 | } |
| 180 | |
| 181 | public Extractor<T, V, C> getTarget() { |
| 182 | return target; |
| 183 | } |
| 184 | |
| 185 | public int[] getMap() { |
| 186 | return map; |
| 187 | } |
| 188 | } |