| 1 | /* |
| 2 | * Copyright 2001-2005 Stephen Colebourne |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.joda.time; |
| 17 | |
| 18 | import java.io.Serializable; |
| 19 | import java.util.Comparator; |
| 20 | |
| 21 | import org.joda.time.convert.ConverterManager; |
| 22 | import org.joda.time.convert.InstantConverter; |
| 23 | |
| 24 | /** |
| 25 | * DateTimeComparator provides comparators to compare one date with another. |
| 26 | * <p> |
| 27 | * Dates may be specified using any object recognised by the |
| 28 | * {@link org.joda.time.convert.ConverterManager ConverterManager} class. |
| 29 | * <p> |
| 30 | * The default objects recognised by the comparator are: |
| 31 | * <ul> |
| 32 | * <li>ReadableInstant |
| 33 | * <li>String |
| 34 | * <li>Calendar |
| 35 | * <li>Date |
| 36 | * <li>Long (milliseconds) |
| 37 | * <li>null (now) |
| 38 | * </ul> |
| 39 | * |
| 40 | * <p> |
| 41 | * DateTimeComparator is thread-safe and immutable. |
| 42 | * |
| 43 | * @author Guy Allard |
| 44 | * @author Stephen Colebourne |
| 45 | * @author Brian S O'Neill |
| 46 | * @since 1.0 |
| 47 | */ |
| 48 | public class DateTimeComparator implements Comparator, Serializable { |
| 49 | |
| 50 | /** Serialization lock */ |
| 51 | private static final long serialVersionUID = -6097339773320178364L; |
| 52 | |
| 53 | /** Singleton instance */ |
| 54 | private static final DateTimeComparator ALL_INSTANCE = new DateTimeComparator(null, null); |
| 55 | /** Singleton instance */ |
| 56 | private static final DateTimeComparator DATE_INSTANCE = new DateTimeComparator(DateTimeFieldType.dayOfYear(), null); |
| 57 | /** Singleton instance */ |
| 58 | private static final DateTimeComparator TIME_INSTANCE = new DateTimeComparator(null, DateTimeFieldType.dayOfYear()); |
| 59 | |
| 60 | /** The lower limit of fields to compare, null if no limit */ |
| 61 | private final DateTimeFieldType iLowerLimit; |
| 62 | /** The upper limit of fields to compare, null if no limit */ |
| 63 | private final DateTimeFieldType iUpperLimit; |
| 64 | |
| 65 | //----------------------------------------------------------------------- |
| 66 | /** |
| 67 | * Returns a DateTimeComparator the compares the entire date time value. |
| 68 | * |
| 69 | * @return a comparator over all fields |
| 70 | */ |
| 71 | public static DateTimeComparator getInstance() { |
| 72 | return ALL_INSTANCE; |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Returns a DateTimeComparator with a lower limit only. Fields of a |
| 77 | * magnitude less than the lower limit are excluded from comparisons. |
| 78 | * |
| 79 | * @param lowerLimit inclusive lower limit for fields to be compared, null means no limit |
| 80 | * @return a comparator over all fields above the lower limit |
| 81 | */ |
| 82 | public static DateTimeComparator getInstance(DateTimeFieldType lowerLimit) { |
| 83 | return getInstance(lowerLimit, null); |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Returns a DateTimeComparator with a lower and upper limit. Fields of a |
| 88 | * magnitude less than the lower limit are excluded from comparisons. |
| 89 | * Fields of a magnitude greater than or equal to the upper limit are also |
| 90 | * excluded from comparisons. Either limit may be specified as null, which |
| 91 | * indicates an unbounded limit. |
| 92 | * |
| 93 | * @param lowerLimit inclusive lower limit for fields to be compared, null means no limit |
| 94 | * @param upperLimit exclusive upper limit for fields to be compared, null means no limit |
| 95 | * @return a comparator over all fields between the limits |
| 96 | */ |
| 97 | public static DateTimeComparator getInstance(DateTimeFieldType lowerLimit, DateTimeFieldType upperLimit) { |
| 98 | if (lowerLimit == null && upperLimit == null) { |
| 99 | return ALL_INSTANCE; |
| 100 | } |
| 101 | if (lowerLimit == DateTimeFieldType.dayOfYear() && upperLimit == null) { |
| 102 | return DATE_INSTANCE; |
| 103 | } |
| 104 | if (lowerLimit == null && upperLimit == DateTimeFieldType.dayOfYear()) { |
| 105 | return TIME_INSTANCE; |
| 106 | } |
| 107 | return new DateTimeComparator(lowerLimit, upperLimit); |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Returns a comparator that only considers date fields. |
| 112 | * Time of day is ignored. |
| 113 | * |
| 114 | * @return a comparator over all date fields |
| 115 | */ |
| 116 | public static DateTimeComparator getDateOnlyInstance() { |
| 117 | return DATE_INSTANCE; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Returns a comparator that only considers time fields. |
| 122 | * Date is ignored. |
| 123 | * |
| 124 | * @return a comparator over all time fields |
| 125 | */ |
| 126 | public static DateTimeComparator getTimeOnlyInstance() { |
| 127 | return TIME_INSTANCE; |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * Restricted constructor. |
| 132 | * |
| 133 | * @param lowerLimit the lower field limit, null means no limit |
| 134 | * @param upperLimit the upper field limit, null means no limit |
| 135 | */ |
| 136 | protected DateTimeComparator(DateTimeFieldType lowerLimit, DateTimeFieldType upperLimit) { |
| 137 | super(); |
| 138 | iLowerLimit = lowerLimit; |
| 139 | iUpperLimit = upperLimit; |
| 140 | } |
| 141 | |
| 142 | //----------------------------------------------------------------------- |
| 143 | /** |
| 144 | * Gets the field type that represents the lower limit of comparison. |
| 145 | * |
| 146 | * @return the field type, null if no upper limit |
| 147 | */ |
| 148 | public DateTimeFieldType getLowerLimit() { |
| 149 | return iLowerLimit; |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Gets the field type that represents the upper limit of comparison. |
| 154 | * |
| 155 | * @return the field type, null if no upper limit |
| 156 | */ |
| 157 | public DateTimeFieldType getUpperLimit() { |
| 158 | return iUpperLimit; |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * Compare two objects against only the range of date time fields as |
| 163 | * specified in the constructor. |
| 164 | * |
| 165 | * @param lhsObj the first object, |
| 166 | * logically on the left of a < comparison, null means now |
| 167 | * @param rhsObj the second object, |
| 168 | * logically on the right of a < comparison, null means now |
| 169 | * @return zero if order does not matter, |
| 170 | * negative value if lhsObj < rhsObj, positive value otherwise. |
| 171 | * @throws IllegalArgumentException if either argument is not supported |
| 172 | */ |
| 173 | public int compare(Object lhsObj, Object rhsObj) { |
| 174 | InstantConverter conv = ConverterManager.getInstance().getInstantConverter(lhsObj); |
| 175 | Chronology lhsChrono = conv.getChronology(lhsObj, (Chronology) null); |
| 176 | long lhsMillis = conv.getInstantMillis(lhsObj, lhsChrono); |
| 177 | |
| 178 | conv = ConverterManager.getInstance().getInstantConverter(rhsObj); |
| 179 | Chronology rhsChrono = conv.getChronology(rhsObj, (Chronology) null); |
| 180 | long rhsMillis = conv.getInstantMillis(rhsObj, rhsChrono); |
| 181 | |
| 182 | if (iLowerLimit != null) { |
| 183 | lhsMillis = iLowerLimit.getField(lhsChrono).roundFloor(lhsMillis); |
| 184 | rhsMillis = iLowerLimit.getField(rhsChrono).roundFloor(rhsMillis); |
| 185 | } |
| 186 | |
| 187 | if (iUpperLimit != null) { |
| 188 | lhsMillis = iUpperLimit.getField(lhsChrono).remainder(lhsMillis); |
| 189 | rhsMillis = iUpperLimit.getField(rhsChrono).remainder(rhsMillis); |
| 190 | } |
| 191 | |
| 192 | if (lhsMillis < rhsMillis) { |
| 193 | return -1; |
| 194 | } else if (lhsMillis > rhsMillis) { |
| 195 | return 1; |
| 196 | } else { |
| 197 | return 0; |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | //----------------------------------------------------------------------- |
| 202 | /** |
| 203 | * Support serialization singletons. |
| 204 | * |
| 205 | * @return the resolved singleton instance |
| 206 | */ |
| 207 | private Object readResolve() { |
| 208 | return getInstance(iLowerLimit, iUpperLimit); |
| 209 | } |
| 210 | |
| 211 | /** |
| 212 | * Compares this comparator to another. |
| 213 | * |
| 214 | * @param object the object to compare to |
| 215 | * @return true if equal |
| 216 | */ |
| 217 | public boolean equals(Object object) { |
| 218 | if (object instanceof DateTimeComparator) { |
| 219 | DateTimeComparator other = (DateTimeComparator) object; |
| 220 | return (iLowerLimit == other.getLowerLimit() || |
| 221 | (iLowerLimit != null && iLowerLimit.equals(other.getLowerLimit()))) && |
| 222 | (iUpperLimit == other.getUpperLimit() || |
| 223 | (iUpperLimit != null && iUpperLimit.equals(other.getUpperLimit()))); |
| 224 | } |
| 225 | return false; |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * Gets a suitable hashcode. |
| 230 | * |
| 231 | * @return the hashcode |
| 232 | */ |
| 233 | public int hashCode() { |
| 234 | return (iLowerLimit == null ? 0 : iLowerLimit.hashCode()) + |
| 235 | (123 * (iUpperLimit == null ? 0 : iUpperLimit.hashCode())); |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * Gets a debugging string. |
| 240 | * |
| 241 | * @return a debugging string |
| 242 | */ |
| 243 | public String toString() { |
| 244 | if (iLowerLimit == iUpperLimit) { |
| 245 | return "DateTimeComparator[" |
| 246 | + (iLowerLimit == null ? "" : iLowerLimit.getName()) |
| 247 | + "]"; |
| 248 | } else { |
| 249 | return "DateTimeComparator[" |
| 250 | + (iLowerLimit == null ? "" : iLowerLimit.getName()) |
| 251 | + "-" |
| 252 | + (iUpperLimit == null ? "" : iUpperLimit.getName()) |
| 253 | + "]"; |
| 254 | } |
| 255 | } |
| 256 | |
| 257 | } |