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A Java library for reading and writing iCalendar (*.ics) files
/**
* Copyright (c) 2012, Ben Fortuna
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* o Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* o Neither the name of Ben Fortuna nor the names of any other contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package net.fortuna.ical4j.model;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import java.io.Serializable;
import java.text.ParseException;
import java.util.*;
/**
* $Id$ [23-Apr-2004]
*
* Defines a list of iCalendar periods. NOTE: By implementing the
* java.util.SortedSet interface period lists will always be
* sorted according to natural ordering.
*
* @author Ben Fortuna
*/
public class PeriodList implements Set, Serializable {
private static final long serialVersionUID = -2317587285790834492L;
private final Set periods;
private TimeZone timezone;
private boolean utc;
private final boolean unmodifiable;
/**
* Default constructor.
*/
public PeriodList() {
this(true);
}
/**
* @param utc indicates whether the period list is in UTC time
*/
public PeriodList(boolean utc) {
this(utc, false);
}
/**
* @param utc indicates whether the period list is in UTC time
*/
public PeriodList(boolean utc, final boolean unmodifiable) {
this.utc = utc;
this.unmodifiable = unmodifiable;
if (unmodifiable) {
periods = Collections.emptySet();
}
else {
periods = new TreeSet();
}
}
/**
* Parses the specified string representation to create a list of periods.
*
* @param aValue
* a string representation of a list of periods
* @throws ParseException
* thrown when an invalid string representation of a period list
* is specified
*/
public PeriodList(final String aValue) throws ParseException {
this();
final StringTokenizer t = new StringTokenizer(aValue, ",");
while (t.hasMoreTokens()) {
add(new Period(t.nextToken()));
}
}
/**
* {@inheritDoc}
*/
public final String toString() {
final StringBuilder b = new StringBuilder();
for (final Iterator i = iterator(); i.hasNext();) {
b.append(i.next().toString());
if (i.hasNext()) {
b.append(',');
}
}
return b.toString();
}
/**
* Add a period to the list.
*
* @param period
* the period to add
* @return true
* @see java.util.List#add(java.lang.Object)
*/
public final boolean add(final Period period) {
if (isUtc()) {
period.setUtc(true);
}
else {
period.setTimeZone(timezone);
}
return periods.add(period);
}
/**
* Remove a period from the list.
*
* @param period
* the period to remove
* @return true if the list contained the specified period
* @see java.util.List#remove(java.lang.Object)
*/
public final boolean remove(final Object period) {
return periods.remove(period);
}
/**
* Returns a normalised version of this period list. Normalisation includes
* combining overlapping periods, removing periods contained by other
* periods, combining adjacent periods, and removing periods that consume
* no time. NOTE: If the period list is
* already normalised then this period list is returned.
*
* @return a period list
*/
public final PeriodList normalise() {
Period prevPeriod = null;
Period period;
final PeriodList newList = new PeriodList(isUtc());
if (timezone != null) {
newList.setTimeZone(timezone);
}
boolean normalised = false;
for (Period period1 : this) {
period = period1;
if (period.isEmpty()) {
period = prevPeriod;
normalised = true;
} else if (prevPeriod != null) {
// ignore periods contained by other periods..
if (prevPeriod.contains(period)) {
period = prevPeriod;
normalised = true;
}
// combine intersecting periods..
else if (prevPeriod.intersects(period)) {
period = prevPeriod.add(period);
normalised = true;
}
// combine adjacent periods..
else if (prevPeriod.adjacent(period)) {
period = prevPeriod.add(period);
normalised = true;
} else {
// if current period is recognised as distinct
// from previous period, add the previous period
// to the list..
newList.add(prevPeriod);
}
}
prevPeriod = period;
}
// remember to add the last period to the list..
if (prevPeriod != null) {
newList.add(prevPeriod);
}
// only return new list if normalisation
// has ocurred..
if (normalised) {
return newList;
}
else {
return this;
}
}
/**
* A convenience method that combines all the periods in the specified list to
* this list. The result returned is a new PeriodList instance, except where
* no periods are specified in the arguments. In such cases this instance is returned.
*
* Normalisation is also performed automatically after all periods have been added.
*
* @param periods a list of periods to add
* @return a period list instance
*/
public final PeriodList add(final PeriodList periods) {
if (periods != null) {
final PeriodList newList = new PeriodList();
newList.addAll(this);
for (final Period p : periods) {
newList.add(p);
}
return newList.normalise();
}
return this;
}
/**
* Subtracts the intersection of this list with the specified list of
* periods from this list and returns the results as a new period list. If
* no intersection is identified this list is returned.
*
* @param subtractions
* a list of periods to subtract from this list
* @return a period list
*/
public final PeriodList subtract(final PeriodList subtractions) {
if (subtractions == null || subtractions.isEmpty()) {
return this;
}
PeriodList result = this;
PeriodList tmpResult = new PeriodList();
for (final Period subtraction : subtractions) {
for (final Period period : result) {
tmpResult.addAll(period.subtract(subtraction));
}
result = tmpResult;
tmpResult = new PeriodList();
}
return result;
}
/**
* Indicates whether this list is in local or UTC format.
* @return Returns true if in UTC format, otherwise false.
*/
public final boolean isUtc() {
return utc;
}
public boolean isUnmodifiable() {
return unmodifiable;
}
/**
* Sets whether this list is in UTC or local time format.
* @param utc The utc to set.
*/
public final void setUtc(final boolean utc) {
for (final Period period : this) {
period.setUtc(utc);
}
this.timezone = null;
this.utc = utc;
}
/**
* Applies the specified timezone to all dates in the list.
* All dates added to this list will also have this timezone
* applied.
* @param timeZone the timezone for the period list
*/
public final void setTimeZone(final TimeZone timeZone) {
for (final Period period : this) {
period.setTimeZone(timeZone);
}
this.timezone = timeZone;
this.utc = false;
}
/**
* @return Returns the timeZone.
*/
public final TimeZone getTimeZone() {
return timezone;
}
/**
* {@inheritDoc}
*/
public boolean addAll(Collection arg0) {
for (Period p : arg0) {
add(p);
}
return true;
}
/**
* {@inheritDoc}
*/
public void clear() {
periods.clear();
}
/**
* {@inheritDoc}
*/
public boolean contains(Object o) {
return periods.contains(o);
}
/**
* {@inheritDoc}
*/
public boolean containsAll(Collection arg0) {
return periods.containsAll(arg0);
}
/**
* {@inheritDoc}
*/
public boolean isEmpty() {
return periods.isEmpty();
}
/**
* {@inheritDoc}
*/
public Iterator iterator() {
return periods.iterator();
}
/**
* {@inheritDoc}
*/
public boolean removeAll(Collection arg0) {
return periods.removeAll(arg0);
}
/**
* {@inheritDoc}
*/
public boolean retainAll(Collection arg0) {
return periods.retainAll(arg0);
}
/**
* {@inheritDoc}
*/
public int size() {
return periods.size();
}
/**
* {@inheritDoc}
*/
public Object[] toArray() {
return periods.toArray();
}
/**
* {@inheritDoc}
*/
public T[] toArray(T[] arg0) {
return periods.toArray(arg0);
}
public boolean equals(Object obj) {
if (!getClass().isAssignableFrom(obj.getClass())) {
return false;
}
final PeriodList rhs = (PeriodList) obj;
return new EqualsBuilder().append(periods, rhs.periods)
.append(timezone, rhs.timezone)
.append(utc, utc)
.isEquals();
}
public int hashCode() {
return new HashCodeBuilder().append(periods)
.append(timezone)
.append(utc)
.toHashCode();
}
}