Java tutorial
/* * Copyright 2010 Martin Grotzke * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * */ package de.javakaffee.web.msm.serializer.javolution; import javolution.text.CharArray; import javolution.xml.stream.XMLStreamException; import org.joda.time.Chronology; import org.joda.time.DateTime; import org.joda.time.DateTimeZone; import org.joda.time.chrono.BuddhistChronology; import org.joda.time.chrono.CopticChronology; import org.joda.time.chrono.EthiopicChronology; import org.joda.time.chrono.GJChronology; import org.joda.time.chrono.GregorianChronology; import org.joda.time.chrono.ISOChronology; import org.joda.time.chrono.IslamicChronology; import org.joda.time.chrono.JulianChronology; /** * A format for joda {@link DateTime}, that stores the millis, chronology and * time zone as separate attributes. If the chronlogy is {@link ISOChronology}, * the attribute is omitted, thus {@link ISOChronology} is seen as default. If * the time zone is the default time zone ({@link DateTimeZone#getDefault()}), * the time zone attribute is omitted. This requires different machines to * have the same time zone settings. * <p> * The following chronologies are supported: * <ul> * <li>{@link ISOChronology}</li> * <li>{@link CopticChronology}</li> * <li>{@link EthiopicChronology}</li> * <li>{@link GregorianChronology}</li> * <li>{@link JulianChronology}</li> * <li>{@link IslamicChronology}</li> * <li>{@link BuddhistChronology}</li> * <li>{@link GJChronology}</li> * </ul> * </p> * * @author <a href="mailto:martin.grotzke@javakaffee.de">Martin Grotzke</a> */ public class JodaDateTimeFormat extends CustomXMLFormat<DateTime> { static final String MILLIS = "millis"; static final String DATE_TIME = "dt"; static final String CHRONOLOGY = "ch"; static final String TIME_ZONE = "tz"; /** * {@inheritDoc} */ @Override public boolean canConvert(final Class<?> cls) { return cls == DateTime.class; } /** * {@inheritDoc} */ @Override public DateTime newInstance(final Class<DateTime> cls, final javolution.xml.XMLFormat.InputElement input) throws XMLStreamException { final long millis = input.getAttribute(MILLIS).toLong(); final Chronology chronology = readChronology(input); final DateTimeZone tz = readTimeZone(input); return new DateTime(millis, chronology.withZone(tz)); } private Chronology readChronology(final javolution.xml.XMLFormat.InputElement input) throws XMLStreamException { final CharArray chronologyId = input.getAttribute(CHRONOLOGY); return IdentifiableChronology.valueOfId(chronologyId != null ? chronologyId.toString() : null); } private DateTimeZone readTimeZone(final javolution.xml.XMLFormat.InputElement input) throws XMLStreamException { final CharArray tz = input.getAttribute(TIME_ZONE); return tz != null ? DateTimeZone.forID(tz.toString()) : DateTimeZone.getDefault(); } /** * {@inheritDoc} */ @Override public void read(final javolution.xml.XMLFormat.InputElement input, final DateTime obj) throws XMLStreamException { // nothing to do } /** * {@inheritDoc} */ @Override public void write(final DateTime obj, final javolution.xml.XMLFormat.OutputElement output) throws XMLStreamException { output.setAttribute(MILLIS, obj.getMillis()); final String chronologyId = getChronologyId(obj.getChronology()); if (chronologyId != null) { output.setAttribute(CHRONOLOGY, chronologyId); } if (obj.getZone() != null && obj.getZone() != DateTimeZone.getDefault()) { output.setAttribute(TIME_ZONE, obj.getZone().getID()); } } private String getChronologyId(final Chronology chronology) { return IdentifiableChronology.getIdByChronology(chronology.getClass()); } /** * An enumeration that provides a String id for subclasses of {@link Chronology}. * For {@link ISOChronology}, <code>null</code> is used as id, as {@link ISOChronology} * is used as default and the id does not have to be serialized. * * @author Martin Grotzke (martin.grotzke@freiheit.com) (initial creation) */ static enum IdentifiableChronology { ISO(null, ISOChronology.getInstance()), COPTIC("COPTIC", CopticChronology.getInstance()), ETHIOPIC( "ETHIOPIC", EthiopicChronology.getInstance()), GREGORIAN("GREGORIAN", GregorianChronology .getInstance()), JULIAN("JULIAN", JulianChronology.getInstance()), ISLAMIC("ISLAMIC", IslamicChronology.getInstance()), BUDDHIST("BUDDHIST", BuddhistChronology.getInstance()), GJ("GJ", GJChronology.getInstance()); private final String _id; private final Chronology _chronology; private IdentifiableChronology(String id, Chronology chronology) { _id = id; _chronology = chronology; } public String getId() { return _id; } /** * Determines the id for the given {@link Chronology} subclass that later * can be used to resolve the {@link Chronology} with {@link #valueOfId(String)}. * For {@link ISOChronology} class <code>null</code> is returned. * * @param clazz a subclass of {@link Chronology}. * @return an id, or <code>null</code> for {@link ISOChronology}. * @throws IllegalArgumentException if the {@link Chronology} is not supported. */ public static String getIdByChronology(Class<? extends Chronology> clazz) throws IllegalArgumentException { for (final IdentifiableChronology item : values()) { if (clazz.equals(item._chronology.getClass())) { return item._id; } } throw new IllegalArgumentException("Chronology not supported: " + clazz.getSimpleName()); } /** * Returns the chronology of the {@link IdentifiableChronology} matching the * provided <code>id</code>. If the provided <code>id</code> is <code>null</code>, * {@link ISOChronology} is returned. * @param id the id from {@link #getIdByChronology(Class)}. * @return a matching {@link Chronology} if any was found. * @throws IllegalArgumentException if no match was found. */ public static Chronology valueOfId(String id) throws IllegalArgumentException { if (id == null) { return ISO._chronology; } for (final IdentifiableChronology item : values()) { if (id.equals(item._id)) { return item._chronology; } } throw new IllegalArgumentException("No chronology found for id " + id); } } }