| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.kernel.se.dto.list; |
| 17 | |
| 18 | import java.util.Arrays; |
| 19 | import java.util.HashSet; |
| 20 | import java.util.Iterator; |
| 21 | import java.util.Set; |
| 22 | |
| 23 | import org.qedeq.kernel.se.base.list.Element; |
| 24 | import org.qedeq.kernel.se.base.list.ElementList; |
| 25 | |
| 26 | |
| 27 | /** |
| 28 | * This class represents a set of {@link org.qedeq.kernel.se.base.list.Element}s. |
| 29 | * |
| 30 | * @author Michael Meyling |
| 31 | */ |
| 32 | public class ElementSet { |
| 33 | |
| 34 | |
| 35 | /** Here are the elements stored. */ |
| 36 | private final Set elements; |
| 37 | |
| 38 | |
| 39 | /** |
| 40 | * Constructs an empty element set. |
| 41 | */ |
| 42 | public ElementSet() { |
| 43 | this.elements = new HashSet(); |
| 44 | } |
| 45 | |
| 46 | |
| 47 | /** |
| 48 | * Constructs an element set. |
| 49 | * |
| 50 | * @param elements the elements to put into the set |
| 51 | * @throws IllegalArgumentException if <code>elements</code> was a NullPointer |
| 52 | */ |
| 53 | public ElementSet(final Element[] elements) { |
| 54 | if (elements == null) { |
| 55 | throw new IllegalArgumentException( |
| 56 | "NullPointer as element array is not allowed"); |
| 57 | } |
| 58 | this.elements = new HashSet(Arrays.asList(elements)); |
| 59 | } |
| 60 | |
| 61 | |
| 62 | /** |
| 63 | * Constructs an element set. |
| 64 | * |
| 65 | * @param set contains the elements to put into the set |
| 66 | * @throws IllegalArgumentException if <code>set</code> was a |
| 67 | * NullPointer |
| 68 | */ |
| 69 | public ElementSet(final ElementSet set) { |
| 70 | if (set == null) { |
| 71 | throw new IllegalArgumentException( |
| 72 | "NullPointer as set is not allowed"); |
| 73 | } |
| 74 | this.elements = new HashSet(set.elements); |
| 75 | } |
| 76 | |
| 77 | |
| 78 | /** |
| 79 | * Constructs an element set from all operands of an element. |
| 80 | * The element must not be a symbol. |
| 81 | * |
| 82 | * @param element contains the elements to put into the set |
| 83 | * (without the operator) |
| 84 | * @throws IllegalArgumentException if <code>element</code> was a |
| 85 | * NullPointer or was an atom. |
| 86 | */ |
| 87 | public ElementSet(final ElementList element) { |
| 88 | if (element == null) { |
| 89 | throw new IllegalArgumentException( |
| 90 | "NullPointer as element is not allowed"); |
| 91 | } |
| 92 | if (element.isAtom()) { |
| 93 | throw new IllegalArgumentException( |
| 94 | "text as element is not allowed"); |
| 95 | } |
| 96 | this.elements = new HashSet(element.getElements()); |
| 97 | } |
| 98 | |
| 99 | |
| 100 | /** |
| 101 | * Is element in set? |
| 102 | * |
| 103 | * @param element Element to check for. |
| 104 | * @return Is <code>element</code> in this set? |
| 105 | * @throws IllegalArgumentException if the element was a |
| 106 | * NullPointer |
| 107 | */ |
| 108 | public final boolean contains(final Element element) { |
| 109 | if (element == null) { |
| 110 | throw new IllegalArgumentException("NullPointer as element is not allowed"); |
| 111 | } |
| 112 | return this.elements.contains(element); |
| 113 | } |
| 114 | |
| 115 | /** |
| 116 | * Is this set empty? |
| 117 | * |
| 118 | * @return Is this set empty? |
| 119 | */ |
| 120 | public final boolean isEmpty() { |
| 121 | return elements.isEmpty(); |
| 122 | } |
| 123 | |
| 124 | |
| 125 | /** |
| 126 | * Is <code>set</code> a superset of this set? |
| 127 | * |
| 128 | * @param set Set to check for. |
| 129 | * @return Is this set a subset of <code>set</code>? |
| 130 | * @throws IllegalArgumentException if the set was a NullPointer |
| 131 | */ |
| 132 | public final boolean isSubset(final ElementSet set) { |
| 133 | if (set == null) { |
| 134 | throw new IllegalArgumentException("NullPointer as set is not allowed"); |
| 135 | } |
| 136 | return set.elements.containsAll(this.elements); |
| 137 | } |
| 138 | |
| 139 | |
| 140 | /** |
| 141 | * Add an element to set. This object is after the method the |
| 142 | * union of this set with {<code>element</code>} |
| 143 | * |
| 144 | * @param element element to put into the set |
| 145 | * @return Possibly changed <code>this</code>. |
| 146 | * @throws IllegalArgumentException if the element was a |
| 147 | * NullPointer |
| 148 | */ |
| 149 | public final ElementSet add(final Element element) { |
| 150 | if (element == null) { |
| 151 | throw new IllegalArgumentException("NullPointer as element is not allowed"); |
| 152 | } |
| 153 | elements.add(element); |
| 154 | return this; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | /** |
| 159 | * Add elements from another {@link ElementSet} to this set. |
| 160 | * After this method this object is the union of the two sets. |
| 161 | * |
| 162 | * @param set add all elements that are here |
| 163 | * @return Possibly changed <code>this</code>. |
| 164 | * @throws IllegalArgumentException if the set was a |
| 165 | * NullPointer |
| 166 | */ |
| 167 | public final ElementSet union(final ElementSet set) { |
| 168 | if (set == null) { |
| 169 | throw new IllegalArgumentException( |
| 170 | "NullPointer as set is not allowed"); |
| 171 | } |
| 172 | elements.addAll(set.elements); |
| 173 | return this; |
| 174 | } |
| 175 | |
| 176 | |
| 177 | /** |
| 178 | * Remove an element from this set. |
| 179 | * |
| 180 | * @param element Element to remove from the set. Must not be <code>null</code>. |
| 181 | * @return Possibly changed <code>this</code>. |
| 182 | * @throws IllegalArgumentException if the element was a |
| 183 | * NullPointer |
| 184 | */ |
| 185 | public final ElementSet remove(final Element element) { |
| 186 | if (element == null) { |
| 187 | throw new IllegalArgumentException( |
| 188 | "NullPointer as element is not allowed"); |
| 189 | } |
| 190 | elements.remove(element); |
| 191 | return this; |
| 192 | } |
| 193 | |
| 194 | |
| 195 | /** |
| 196 | * Remove elements from another {@link ElementSet} from this set. |
| 197 | * After this method this object is the asymmetric set difference of the |
| 198 | * two sets: <code>this</code> \ <code>set</code>. |
| 199 | * |
| 200 | * @param set Remove all elements that are in this set from |
| 201 | * <code>this</code>. |
| 202 | * @return Possibly changed <code>this</code>. |
| 203 | * @throws IllegalArgumentException if the set was a |
| 204 | * NullPointer |
| 205 | */ |
| 206 | public final ElementSet minus(final ElementSet set) { |
| 207 | if (set == null) { |
| 208 | throw new IllegalArgumentException( |
| 209 | "NullPointer as set is not allowed"); |
| 210 | } |
| 211 | this.elements.removeAll(set.elements); |
| 212 | return this; |
| 213 | } |
| 214 | |
| 215 | |
| 216 | /** |
| 217 | * Build the intersection. |
| 218 | * |
| 219 | * @param set Check for these elements. |
| 220 | * @return Possibly changed <code>this</code>. |
| 221 | * @throws IllegalArgumentException if the set was a |
| 222 | * NullPointer |
| 223 | */ |
| 224 | public final ElementSet intersection(final ElementSet set) { |
| 225 | if (set == null) { |
| 226 | throw new IllegalArgumentException( |
| 227 | "NullPointer as set is not allowed"); |
| 228 | } |
| 229 | this.elements.retainAll(set.elements); |
| 230 | return this; |
| 231 | } |
| 232 | |
| 233 | |
| 234 | /** |
| 235 | * Build a new intersection. |
| 236 | * |
| 237 | * @param set check for these elements |
| 238 | * @return New instance that contains all elements that were in <code>this</code> |
| 239 | * and <code>set</code>. |
| 240 | * @throws IllegalArgumentException if the set was a |
| 241 | * NullPointer |
| 242 | */ |
| 243 | public final ElementSet newIntersection(final ElementSet set) { |
| 244 | if (set == null) { |
| 245 | throw new IllegalArgumentException( |
| 246 | "NullPointer as set is not allowed"); |
| 247 | } |
| 248 | final ElementSet result = new ElementSet(this); |
| 249 | result.elements.retainAll(set.elements); |
| 250 | return result; |
| 251 | } |
| 252 | |
| 253 | |
| 254 | /** |
| 255 | * Return all elements that are only in one of both sets. |
| 256 | * This method returns a new instance that holds the symmetric set difference of the |
| 257 | * two sets. The original set is not modified. |
| 258 | * |
| 259 | * @param set Build the symmetric difference with this set. |
| 260 | * <code>this</code> |
| 261 | * @return Symmetric difference. |
| 262 | * @throws IllegalArgumentException if the set was a |
| 263 | * NullPointer |
| 264 | */ |
| 265 | public final ElementSet newDelta(final ElementSet set) { |
| 266 | if (set == null) { |
| 267 | throw new IllegalArgumentException( |
| 268 | "NullPointer as set is not allowed"); |
| 269 | } |
| 270 | final ElementSet union = new ElementSet(this); |
| 271 | union.union(set); |
| 272 | final ElementSet intersection = new ElementSet(this); |
| 273 | intersection.intersection(set); |
| 274 | union.minus(intersection); |
| 275 | return union; |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * Get number of elements. |
| 280 | * |
| 281 | * @return Number of elements in this set. |
| 282 | */ |
| 283 | public final int size() { |
| 284 | return this.elements.size(); |
| 285 | } |
| 286 | |
| 287 | /** |
| 288 | * Returns an iterator over the elements in this set. The elements are |
| 289 | * returned in no particular order (unless this set is an instance of some |
| 290 | * class that provides a guarantee). |
| 291 | * |
| 292 | * @return Iterator over the elements in this set. |
| 293 | */ |
| 294 | public Iterator iterator() { |
| 295 | return this.elements.iterator(); |
| 296 | } |
| 297 | |
| 298 | public final boolean equals(final Object obj) { |
| 299 | if (obj == null) { |
| 300 | return false; |
| 301 | } |
| 302 | if (obj.getClass() == ElementSet.class) { |
| 303 | return this.elements.equals(((ElementSet) obj).elements); |
| 304 | } |
| 305 | return false; |
| 306 | } |
| 307 | |
| 308 | public final int hashCode() { |
| 309 | return elements.hashCode(); |
| 310 | } |
| 311 | |
| 312 | public final String toString() { |
| 313 | final StringBuffer result = new StringBuffer(); |
| 314 | result.append("{"); |
| 315 | final Iterator iterator = elements.iterator(); |
| 316 | while (iterator.hasNext()) { |
| 317 | result.append(iterator.next()); |
| 318 | if (iterator.hasNext()) { |
| 319 | result.append(", "); |
| 320 | } |
| 321 | } |
| 322 | result.append("}"); |
| 323 | return result.toString(); |
| 324 | } |
| 325 | |
| 326 | } |