michael@0: /**
michael@0:  * Copyright (c) 2012, Ben Fortuna
michael@0:  * All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  *
michael@0:  *  o Redistributions of source code must retain the above copyright
michael@0:  * notice, this list of conditions and the following disclaimer.
michael@0:  *
michael@0:  *  o Redistributions in binary form must reproduce the above copyright
michael@0:  * notice, this list of conditions and the following disclaimer in the
michael@0:  * documentation and/or other materials provided with the distribution.
michael@0:  *
michael@0:  *  o Neither the name of Ben Fortuna nor the names of any other contributors
michael@0:  * may be used to endorse or promote products derived from this software
michael@0:  * without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0:  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0:  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0:  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
michael@0:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
michael@0:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
michael@0:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
michael@0:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
michael@0:  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
michael@0:  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
michael@0:  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: package net.fortuna.ical4j.model.component;
michael@0: 
michael@0: import java.io.IOException;
michael@0: import java.text.DateFormat;
michael@0: import java.text.ParseException;
michael@0: import java.text.SimpleDateFormat;
michael@0: import java.util.Arrays;
michael@0: import java.util.Calendar;
michael@0: import java.util.Collections;
michael@0: import java.util.Iterator;
michael@0: import java.util.Map;
michael@0: import java.util.TreeMap;
michael@0: 
michael@0: import net.fortuna.ical4j.model.Component;
michael@0: import net.fortuna.ical4j.model.Date;
michael@0: import net.fortuna.ical4j.model.DateList;
michael@0: import net.fortuna.ical4j.model.DateTime;
michael@0: import net.fortuna.ical4j.model.Property;
michael@0: import net.fortuna.ical4j.model.PropertyList;
michael@0: import net.fortuna.ical4j.model.ValidationException;
michael@0: import net.fortuna.ical4j.model.parameter.Value;
michael@0: import net.fortuna.ical4j.model.property.DtStart;
michael@0: import net.fortuna.ical4j.model.property.RDate;
michael@0: import net.fortuna.ical4j.model.property.RRule;
michael@0: import net.fortuna.ical4j.model.property.TzOffsetFrom;
michael@0: import net.fortuna.ical4j.model.property.TzOffsetTo;
michael@0: import net.fortuna.ical4j.util.Dates;
michael@0: import net.fortuna.ical4j.util.PropertyValidator;
michael@0: import net.fortuna.ical4j.util.TimeZones;
michael@0: 
michael@0: import org.apache.commons.logging.Log;
michael@0: import org.apache.commons.logging.LogFactory;
michael@0: 
michael@0: /**
michael@0:  * $Id$ [05-Apr-2004]
michael@0:  *
michael@0:  * Defines an iCalendar sub-component representing a timezone observance. Class made abstract such that only Standard
michael@0:  * and Daylight instances are valid.
michael@0:  * @author Ben Fortuna
michael@0:  */
michael@0: public abstract class Observance extends Component {
michael@0: 
michael@0:     /**
michael@0:      * 
michael@0:      */
michael@0:     private static final long serialVersionUID = 2523330383042085994L;
michael@0: 
michael@0:     /**
michael@0:      * one of 'standardc' or 'daylightc' MUST occur and each MAY occur more than once.
michael@0:      */
michael@0:     public static final String STANDARD = "STANDARD";
michael@0: 
michael@0:     /**
michael@0:      * Token for daylight observance.
michael@0:      */
michael@0:     public static final String DAYLIGHT = "DAYLIGHT";
michael@0: 
michael@0:     // TODO: clear cache when observance definition changes (??)
michael@0:     private long[] onsetsMillisec;
michael@0:     private DateTime[] onsetsDates;
michael@0:     private Map onsets = new TreeMap();
michael@0:     private Date initialOnset = null;
michael@0:     
michael@0:     /**
michael@0:      * Used for parsing times in a UTC date-time representation.
michael@0:      */
michael@0:     private static final String UTC_PATTERN = "yyyyMMdd'T'HHmmss";
michael@0:     private static final DateFormat UTC_FORMAT = new SimpleDateFormat(
michael@0:             UTC_PATTERN);
michael@0:     
michael@0:     static {
michael@0:         UTC_FORMAT.setTimeZone(TimeZones.getUtcTimeZone());
michael@0:         UTC_FORMAT.setLenient(false);
michael@0:     }
michael@0: 
michael@0:     /* If this is set we have rrules. If we get a date after this rebuild onsets */
michael@0:     private Date onsetLimit;
michael@0: 
michael@0:     /**
michael@0:      * Constructs a timezone observance with the specified name and no properties.
michael@0:      * @param name the name of this observance component
michael@0:      */
michael@0:     protected Observance(final String name) {
michael@0:         super(name);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Constructor protected to enforce use of sub-classes from this library.
michael@0:      * @param name the name of the time type
michael@0:      * @param properties a list of properties
michael@0:      */
michael@0:     protected Observance(final String name, final PropertyList properties) {
michael@0:         super(name, properties);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * {@inheritDoc}
michael@0:      */
michael@0:     public final void validate(final boolean recurse) throws ValidationException {
michael@0: 
michael@0:         // From "4.8.3.3 Time Zone Offset From":
michael@0:         // Conformance: This property MUST be specified in a "VTIMEZONE"
michael@0:         // calendar component.
michael@0:         PropertyValidator.getInstance().assertOne(Property.TZOFFSETFROM,
michael@0:                 getProperties());
michael@0: 
michael@0:         // From "4.8.3.4 Time Zone Offset To":
michael@0:         // Conformance: This property MUST be specified in a "VTIMEZONE"
michael@0:         // calendar component.
michael@0:         PropertyValidator.getInstance().assertOne(Property.TZOFFSETTO,
michael@0:                 getProperties());
michael@0: 
michael@0:         /*
michael@0:          * ; the following are each REQUIRED, ; but MUST NOT occur more than once dtstart / tzoffsetto / tzoffsetfrom /
michael@0:          */
michael@0:         PropertyValidator.getInstance().assertOne(Property.DTSTART,
michael@0:                 getProperties());
michael@0: 
michael@0:         /*
michael@0:          * ; the following are optional, ; and MAY occur more than once comment / rdate / rrule / tzname / x-prop
michael@0:          */
michael@0: 
michael@0:         if (recurse) {
michael@0:             validateProperties();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the latest applicable onset of this observance for the specified date.
michael@0:      * @param date the latest date that an observance onset may occur
michael@0:      * @return the latest applicable observance date or null if there is no applicable observance onset for the
michael@0:      * specified date
michael@0:      */
michael@0:     public final Date getLatestOnset(final Date date) {
michael@0:         
michael@0:         if (initialOnset == null) {
michael@0:             try {
michael@0:                 initialOnset = applyOffsetFrom(calculateOnset(((DtStart) getProperty(Property.DTSTART)).getDate()));
michael@0:             } catch (ParseException e) {
michael@0:                 Log log = LogFactory.getLog(Observance.class);
michael@0:                 log.error("Unexpected error calculating initial onset", e);
michael@0:                 // XXX: is this correct?
michael@0:                 return null;
michael@0:             }
michael@0:         }
michael@0:         
michael@0:         // observance not applicable if date is before the effective date of this observance..
michael@0:         if (date.before(initialOnset)) {
michael@0:             return null;
michael@0:         }
michael@0: 
michael@0:         if ((onsetsMillisec != null) && (onsetLimit == null || date.before(onsetLimit))) {
michael@0:             return getCachedOnset(date);
michael@0:         }
michael@0: 
michael@0:         Date onset = initialOnset;
michael@0:         Date initialOnsetUTC;
michael@0:         // get first onset without adding TZFROM as this may lead to a day boundary
michael@0:         // change which would be incompatible with BYDAY RRULES
michael@0:         // we will have to add the offset to all cacheable onsets
michael@0:         try {
michael@0:             initialOnsetUTC = calculateOnset(((DtStart) getProperty(Property.DTSTART)).getDate());
michael@0:         } catch (ParseException e) {
michael@0:             Log log = LogFactory.getLog(Observance.class);
michael@0:             log.error("Unexpected error calculating initial onset", e);
michael@0:             // XXX: is this correct?
michael@0:             return null;
michael@0:         }
michael@0:         // collect all onsets for the purposes of caching..
michael@0:         final DateList cacheableOnsets = new DateList();
michael@0:         cacheableOnsets.setUtc(true);
michael@0:         cacheableOnsets.add(initialOnset);
michael@0: 
michael@0:         // check rdates for latest applicable onset..
michael@0:         final PropertyList rdates = getProperties(Property.RDATE);
michael@0:         for (final Iterator i = rdates.iterator(); i.hasNext();) {
michael@0:             final RDate rdate = (RDate) i.next();
michael@0:             for (final Iterator j = rdate.getDates().iterator(); j.hasNext();) {
michael@0:                 try {
michael@0:                     final DateTime rdateOnset = applyOffsetFrom(calculateOnset((Date) j.next()));
michael@0:                     if (!rdateOnset.after(date) && rdateOnset.after(onset)) {
michael@0:                         onset = rdateOnset;
michael@0:                     }
michael@0:                     /*
michael@0:                      * else if (rdateOnset.after(date) && rdateOnset.after(onset) && (nextOnset == null ||
michael@0:                      * rdateOnset.before(nextOnset))) { nextOnset = rdateOnset; }
michael@0:                      */
michael@0:                     cacheableOnsets.add(rdateOnset);
michael@0:                 } catch (ParseException e) {
michael@0:                     Log log = LogFactory.getLog(Observance.class);
michael@0:                     log.error("Unexpected error calculating onset", e);
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // check recurrence rules for latest applicable onset..
michael@0:         final PropertyList rrules = getProperties(Property.RRULE);
michael@0:         for (final Iterator i = rrules.iterator(); i.hasNext();) {
michael@0:             final RRule rrule = (RRule) i.next();
michael@0:             // include future onsets to determine onset period..
michael@0:             final Calendar cal = Dates.getCalendarInstance(date);
michael@0:             cal.setTime(date);
michael@0:             cal.add(Calendar.YEAR, 10);
michael@0:             onsetLimit = Dates.getInstance(cal.getTime(), Value.DATE_TIME);
michael@0:             final DateList recurrenceDates = rrule.getRecur().getDates(initialOnsetUTC,
michael@0:                     onsetLimit, Value.DATE_TIME);
michael@0:             for (final Iterator j = recurrenceDates.iterator(); j.hasNext();) {
michael@0:                 final DateTime rruleOnset = applyOffsetFrom((DateTime) j.next());
michael@0:                 if (!rruleOnset.after(date) && rruleOnset.after(onset)) {
michael@0:                     onset = rruleOnset;
michael@0:                 }
michael@0:                 /*
michael@0:                  * else if (rruleOnset.after(date) && rruleOnset.after(onset) && (nextOnset == null ||
michael@0:                  * rruleOnset.before(nextOnset))) { nextOnset = rruleOnset; }
michael@0:                  */
michael@0:                 cacheableOnsets.add(rruleOnset);
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // cache onsets..
michael@0:         Collections.sort(cacheableOnsets);
michael@0:         DateTime cacheableOnset = null;
michael@0:         this.onsetsMillisec = new long[cacheableOnsets.size()];
michael@0:         this.onsetsDates = new DateTime[onsetsMillisec.length];
michael@0: 
michael@0:         for (int i = 0; i < onsetsMillisec.length; i++) {
michael@0:             cacheableOnset = (DateTime)cacheableOnsets.get(i);
michael@0:             onsetsMillisec[i] = cacheableOnset.getTime();
michael@0:             onsetsDates[i] = cacheableOnset;
michael@0:         }
michael@0: 
michael@0:         return onset;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns a cached onset for the specified date.
michael@0:      * @param date
michael@0:      * @return a cached onset date or null if no cached onset is applicable for the specified date
michael@0:      */
michael@0:     private DateTime getCachedOnset(final Date date) {
michael@0:         int index = Arrays.binarySearch(onsetsMillisec, date.getTime());
michael@0:         if (index >= 0) {
michael@0:             return onsetsDates[index];
michael@0:         } else {
michael@0:             int insertionIndex = -index -1;
michael@0:             return onsetsDates[insertionIndex -1];
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the mandatory dtstart property.
michael@0:      * @return the DTSTART property or null if not specified
michael@0:      */
michael@0:     public final DtStart getStartDate() {
michael@0:         return (DtStart) getProperty(Property.DTSTART);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the mandatory tzoffsetfrom property.
michael@0:      * @return the TZOFFSETFROM property or null if not specified
michael@0:      */
michael@0:     public final TzOffsetFrom getOffsetFrom() {
michael@0:         return (TzOffsetFrom) getProperty(Property.TZOFFSETFROM);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the mandatory tzoffsetto property.
michael@0:      * @return the TZOFFSETTO property or null if not specified
michael@0:      */
michael@0:     public final TzOffsetTo getOffsetTo() {
michael@0:         return (TzOffsetTo) getProperty(Property.TZOFFSETTO);
michael@0:     }
michael@0:     
michael@0: //    private Date calculateOnset(DateProperty dateProperty) {
michael@0: //        return calculateOnset(dateProperty.getValue());
michael@0: //    }
michael@0: //    
michael@0:     private DateTime calculateOnset(Date date) throws ParseException {
michael@0:         return calculateOnset(date.toString());
michael@0:     }
michael@0:     
michael@0:     private DateTime calculateOnset(String dateStr) throws ParseException {
michael@0:         
michael@0:         // Translate local onset into UTC time by parsing local time 
michael@0:         // as GMT and adjusting by TZOFFSETFROM if required
michael@0:         long utcOnset;
michael@0:        
michael@0:         synchronized (UTC_FORMAT) {
michael@0:             utcOnset = UTC_FORMAT.parse(dateStr).getTime();
michael@0:         }
michael@0: 
michael@0:         // return a UTC
michael@0:         DateTime onset = new DateTime(true);
michael@0:         onset.setTime(utcOnset);
michael@0:         return onset;
michael@0:     }
michael@0: 
michael@0:     private DateTime applyOffsetFrom(DateTime orig) {
michael@0:         DateTime withOffset = new DateTime(true);
michael@0:         withOffset.setTime(orig.getTime() - getOffsetFrom().getOffset().getOffset());
michael@0:         return withOffset;
michael@0:     }
michael@0: }