/*
* Copyright (c) 2010 The University of Reading
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the University of Reading, nor the names of the
* authors or contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package uk.ac.rdg.resc.edal.time;
import org.joda.time.DateTimeField;
import org.joda.time.DateTimeFieldType;
import org.joda.time.DurationField;
import org.joda.time.IllegalFieldValueException;
import org.joda.time.field.ImpreciseDateTimeField;
/**
* A {@link DateTimeField} representing a month within a year of fixed duration.
* @author Jon
*/
final class MonthOfFixedYearDateTimeField extends ImpreciseDateTimeField {
private final FixedYearVariableMonthChronology chron;
private final int[] daysInMonth;
private final int numMonthsInYear;
public MonthOfFixedYearDateTimeField(FixedYearVariableMonthChronology chron) {
super(DateTimeFieldType.monthOfYear(), chron.getAverageMillisInMonth());
this.chron = chron;
this.daysInMonth = chron.getMonthLengths();
this.numMonthsInYear = chron.getMonthLengths().length;
}
@Override
public int get(long instant) {
int dayOfYear = this.chron.dayOfYear().get(instant);
// Now search through the months of the year
int totalDays = 0;
for (int i = 0; i < daysInMonth.length; i++) {
totalDays += daysInMonth[i];
if (dayOfYear <= totalDays) {
return i + 1; // Month numbers are one-based
}
}
throw new AssertionError("Shouldn't get here");
}
@Override
public long set(long instant, int value) {
// Check for illegal values: this is not a lenient field
if (value < 1 || value > this.numMonthsInYear) {
throw new IllegalFieldValueException(this.getType(), value, 1, this.numMonthsInYear);
}
// What is the current month?
int monthOfYear = this.get(instant);
// How many months do we have to add to arrive at the new value
int monthsToAdd = value - monthOfYear;
// Now add the required number of months
return this.add(instant, monthsToAdd);
}
@Override
public long add(final long instant, final int numMonths) {
if (numMonths == 0) return instant;
// Calculate the number of years we have to add
int numYearsToAdd = numMonths / this.numMonthsInYear;
// Add the required number of years to the millisecond instant
long newInstant = instant + numYearsToAdd * this.chron.years().getUnitMillis();
// What is the current month?
int monthOfYear = this.get(instant);
// Calculate the number of months we have to add
int numMonthsToAdd = numMonths % this.numMonthsInYear;
// Add the required number of months TODO!!!
if (numMonthsToAdd > 0) {
// Add the months, starting with the current month
for (int i = 0; i < numMonthsToAdd; i++) {
// monthOfYear is 1-based
int monthToAdd = monthOfYear - 1 + i;
// we might wrap around the array
monthToAdd %= this.numMonthsInYear;
long millisToAdd = this.daysInMonth[monthToAdd] * this.chron.days().getUnitMillis();
newInstant += millisToAdd;
}
} else if (numMonthsToAdd < 0) {
// Subtract the month lengths, starting with the previous month
for (int i = 0; i < Math.abs(numMonthsToAdd); i++) {
// The previous month is monthOfYear - 2 because monthOfYear is 1-based
int monthToSubtract = monthOfYear - 2 - i;
// we might wrap around the array
if (monthToSubtract < 0) monthToSubtract += this.numMonthsInYear;
long millisToSubtract = this.daysInMonth[monthToSubtract] * this.chron.days().getUnitMillis();
newInstant -= millisToSubtract;
}
}
return newInstant;
}
@Override
public long add(long instant, long numMonths) {
// TODO: should do a better check for overflow here
if (numMonths > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Value too large");
}
return this.add(instant, (int)numMonths);
}
@Override
public long roundFloor(long instant) {
int year = this.chron.year().get(instant);
int monthOfYear = this.get(instant);
int numCompleteMonths = monthOfYear - 1;
long millis = (year - 1970) * this.chron.years().getUnitMillis();
for (int i = 0; i < numCompleteMonths; i++) {
millis += this.daysInMonth[i] * this.chron.days().getUnitMillis();
}
return millis;
}
@Override
public int getMinimumValue() { return 1; }
@Override
public int getMaximumValue() { return this.numMonthsInYear; }
@Override
public DurationField getRangeDurationField() {
return this.chron.years();
}
/** Always returns false: does not accept impossible months like Floopuary */
@Override
public boolean isLenient() { return false; }
}