fm.last.commons.lang.time.DateRange.java Source code

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Here is the source code for fm.last.commons.lang.time.DateRange.java

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/*
 * Copyright 2012 Last.fm
 *
 *  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 fm.last.commons.lang.time;

import java.util.Iterator;

import org.joda.time.LocalDate;
import org.joda.time.Period;
import org.joda.time.PeriodType;

/**
 * Represents an Iterable range of LocalDates. This is a discrete set of LocalDates, which makes it distinct from the
 * joda-time Interval class, which represents a continuous interval between two precise Instants.
 */
public class DateRange implements Iterable<LocalDate> {

    private final LocalDate firstDate;
    private final LocalDate lastDate;

    /**
     * Create a new DateRange from firstDate to lastDate (inclusive)
     * 
     * @param firstDate - First LocalDate in the DateRange
     * @param lastDate - Last LocalDate in the DateRange
     */
    public DateRange(LocalDate firstDate, LocalDate lastDate) {
        validateDates(firstDate, lastDate);
        this.firstDate = firstDate;
        this.lastDate = lastDate;
    }

    private void validateDates(LocalDate firstDate, LocalDate lastDate) {
        if (firstDate == null) {
            throw new IllegalArgumentException("First date cannot be null");
        }
        if (lastDate == null) {
            throw new IllegalArgumentException("Last date cannot be null");
        }
        if (firstDate.isAfter(lastDate)) {
            throw new IllegalArgumentException("First date cannot be after last date");
        }
    }

    @Override
    public Iterator<LocalDate> iterator() {
        return new DateRangeIterator();
    }

    public LocalDate getFirstDate() {
        return firstDate;
    }

    public LocalDate getLastDate() {
        return lastDate;
    }

    /**
     * @return The number of days (inclusive) between the first and last dates in the range
     */
    public int numberOfDays() {
        Period period = new Period(firstDate, lastDate, PeriodType.days());
        return period.getDays() + 1; // Add one to be inclusive of lastDate as well
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + firstDate.hashCode();
        result = prime * result + lastDate.hashCode();
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof DateRange)) {
            return false;
        }
        DateRange other = (DateRange) obj;
        if (!firstDate.equals(other.firstDate)) {
            return false;
        }
        if (!lastDate.equals(other.lastDate)) {
            return false;
        }
        return true;
    }

    private class DateRangeIterator implements Iterator<LocalDate> {
        private LocalDate currentDate;

        private DateRangeIterator() {
            currentDate = firstDate;
        }

        @Override
        public boolean hasNext() {
            return !currentDate.isAfter(lastDate);
        }

        @Override
        public LocalDate next() {
            LocalDate current = currentDate;
            currentDate = currentDate.plusDays(1);
            return current;
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Cannot remove a LocalDate from a DateRange");
        }

    }
}