| 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.chrono; |
| 17 | |
| 18 | import java.io.IOException; |
| 19 | import java.io.ObjectInputStream; |
| 20 | import java.io.ObjectOutputStream; |
| 21 | import java.io.Serializable; |
| 22 | import java.util.HashMap; |
| 23 | import java.util.Map; |
| 24 | |
| 25 | import org.joda.time.Chronology; |
| 26 | import org.joda.time.DateTimeFieldType; |
| 27 | import org.joda.time.DateTimeZone; |
| 28 | import org.joda.time.field.DividedDateTimeField; |
| 29 | import org.joda.time.field.RemainderDateTimeField; |
| 30 | |
| 31 | /** |
| 32 | * Implements a chronology that follows the rules of the ISO8601 standard, |
| 33 | * which is compatible with Gregorian for all modern dates. |
| 34 | * When ISO does not define a field, but it can be determined (such as AM/PM) |
| 35 | * it is included. |
| 36 | * <p> |
| 37 | * With the exception of century related fields, ISOChronology is exactly the |
| 38 | * same as {@link GregorianChronology}. In this chronology, centuries and year |
| 39 | * of century are zero based. For all years, the century is determined by |
| 40 | * dropping the last two digits of the year, ignoring sign. The year of century |
| 41 | * is the value of the last two year digits. |
| 42 | * <p> |
| 43 | * ISOChronology is thread-safe and immutable. |
| 44 | * |
| 45 | * @author Stephen Colebourne |
| 46 | * @author Brian S O'Neill |
| 47 | * @since 1.0 |
| 48 | */ |
| 49 | public final class ISOChronology extends AssembledChronology { |
| 50 | |
| 51 | /** Serialization lock */ |
| 52 | private static final long serialVersionUID = -6212696554273812441L; |
| 53 | |
| 54 | /** Singleton instance of a UTC ISOChronology */ |
| 55 | private static final ISOChronology INSTANCE_UTC; |
| 56 | |
| 57 | private static final int FAST_CACHE_SIZE = 64; |
| 58 | |
| 59 | /** Fast cache of zone to chronology */ |
| 60 | private static final ISOChronology[] cFastCache; |
| 61 | |
| 62 | /** Cache of zone to chronology */ |
| 63 | private static final Map cCache = new HashMap(); |
| 64 | static { |
| 65 | cFastCache = new ISOChronology[FAST_CACHE_SIZE]; |
| 66 | INSTANCE_UTC = new ISOChronology(GregorianChronology.getInstanceUTC()); |
| 67 | cCache.put(DateTimeZone.UTC, INSTANCE_UTC); |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * Gets an instance of the ISOChronology. |
| 72 | * The time zone of the returned instance is UTC. |
| 73 | * |
| 74 | * @return a singleton UTC instance of the chronology |
| 75 | */ |
| 76 | public static ISOChronology getInstanceUTC() { |
| 77 | return INSTANCE_UTC; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Gets an instance of the ISOChronology in the default time zone. |
| 82 | * |
| 83 | * @return a chronology in the default time zone |
| 84 | */ |
| 85 | public static ISOChronology getInstance() { |
| 86 | return getInstance(DateTimeZone.getDefault()); |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Gets an instance of the ISOChronology in the given time zone. |
| 91 | * |
| 92 | * @param zone the time zone to get the chronology in, null is default |
| 93 | * @return a chronology in the specified time zone |
| 94 | */ |
| 95 | public static ISOChronology getInstance(DateTimeZone zone) { |
| 96 | if (zone == null) { |
| 97 | zone = DateTimeZone.getDefault(); |
| 98 | } |
| 99 | int index = System.identityHashCode(zone) & (FAST_CACHE_SIZE - 1); |
| 100 | ISOChronology chrono = cFastCache[index]; |
| 101 | if (chrono != null && chrono.getZone() == zone) { |
| 102 | return chrono; |
| 103 | } |
| 104 | synchronized (cCache) { |
| 105 | chrono = (ISOChronology) cCache.get(zone); |
| 106 | if (chrono == null) { |
| 107 | chrono = new ISOChronology(ZonedChronology.getInstance(INSTANCE_UTC, zone)); |
| 108 | cCache.put(zone, chrono); |
| 109 | } |
| 110 | } |
| 111 | cFastCache[index] = chrono; |
| 112 | return chrono; |
| 113 | } |
| 114 | |
| 115 | // Constructors and instance variables |
| 116 | //----------------------------------------------------------------------- |
| 117 | |
| 118 | /** |
| 119 | * Restricted constructor |
| 120 | */ |
| 121 | private ISOChronology(Chronology base) { |
| 122 | super(base, null); |
| 123 | } |
| 124 | |
| 125 | // Conversion |
| 126 | //----------------------------------------------------------------------- |
| 127 | /** |
| 128 | * Gets the Chronology in the UTC time zone. |
| 129 | * |
| 130 | * @return the chronology in UTC |
| 131 | */ |
| 132 | public Chronology withUTC() { |
| 133 | return INSTANCE_UTC; |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Gets the Chronology in a specific time zone. |
| 138 | * |
| 139 | * @param zone the zone to get the chronology in, null is default |
| 140 | * @return the chronology |
| 141 | */ |
| 142 | public Chronology withZone(DateTimeZone zone) { |
| 143 | if (zone == null) { |
| 144 | zone = DateTimeZone.getDefault(); |
| 145 | } |
| 146 | if (zone == getZone()) { |
| 147 | return this; |
| 148 | } |
| 149 | return getInstance(zone); |
| 150 | } |
| 151 | |
| 152 | // Output |
| 153 | //----------------------------------------------------------------------- |
| 154 | /** |
| 155 | * Gets a debugging toString. |
| 156 | * |
| 157 | * @return a debugging string |
| 158 | */ |
| 159 | public String toString() { |
| 160 | String str = "ISOChronology"; |
| 161 | DateTimeZone zone = getZone(); |
| 162 | if (zone != null) { |
| 163 | str = str + '[' + zone.getID() + ']'; |
| 164 | } |
| 165 | return str; |
| 166 | } |
| 167 | |
| 168 | protected void assemble(Fields fields) { |
| 169 | if (getBase().getZone() == DateTimeZone.UTC) { |
| 170 | // Use zero based century and year of century. |
| 171 | fields.centuryOfEra = new DividedDateTimeField( |
| 172 | ISOYearOfEraDateTimeField.INSTANCE, DateTimeFieldType.centuryOfEra(), 100); |
| 173 | fields.yearOfCentury = new RemainderDateTimeField( |
| 174 | (DividedDateTimeField) fields.centuryOfEra, DateTimeFieldType.yearOfCentury()); |
| 175 | fields.weekyearOfCentury = new RemainderDateTimeField( |
| 176 | (DividedDateTimeField) fields.centuryOfEra, DateTimeFieldType.weekyearOfCentury()); |
| 177 | |
| 178 | fields.centuries = fields.centuryOfEra.getDurationField(); |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * Checks if this chronology instance equals another. |
| 184 | * |
| 185 | * @param obj the object to compare to |
| 186 | * @return true if equal |
| 187 | * @since 1.6 |
| 188 | */ |
| 189 | public boolean equals(Object obj) { |
| 190 | return super.equals(obj); |
| 191 | } |
| 192 | |
| 193 | /** |
| 194 | * A suitable hash code for the chronology. |
| 195 | * |
| 196 | * @return the hash code |
| 197 | * @since 1.6 |
| 198 | */ |
| 199 | public int hashCode() { |
| 200 | return "ISO".hashCode() * 11 + getZone().hashCode(); |
| 201 | } |
| 202 | |
| 203 | /** |
| 204 | * Serialize ISOChronology instances using a small stub. This reduces the |
| 205 | * serialized size, and deserialized instances come from the cache. |
| 206 | */ |
| 207 | private Object writeReplace() { |
| 208 | return new Stub(getZone()); |
| 209 | } |
| 210 | |
| 211 | private static final class Stub implements Serializable { |
| 212 | private static final long serialVersionUID = -6212696554273812441L; |
| 213 | |
| 214 | private transient DateTimeZone iZone; |
| 215 | |
| 216 | Stub(DateTimeZone zone) { |
| 217 | iZone = zone; |
| 218 | } |
| 219 | |
| 220 | private Object readResolve() { |
| 221 | return ISOChronology.getInstance(iZone); |
| 222 | } |
| 223 | |
| 224 | private void writeObject(ObjectOutputStream out) throws IOException { |
| 225 | out.writeObject(iZone); |
| 226 | } |
| 227 | |
| 228 | private void readObject(ObjectInputStream in) |
| 229 | throws IOException, ClassNotFoundException |
| 230 | { |
| 231 | iZone = (DateTimeZone)in.readObject(); |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | } |