com.google.android.apps.paco.EsmGenerator2.java Source code

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Here is the source code for com.google.android.apps.paco.EsmGenerator2.java

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/*
* Copyright 2011 Google Inc. All Rights Reserved.
*
* 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 com.google.android.apps.paco;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

import org.joda.time.DateTime;
import org.joda.time.Interval;
import org.joda.time.Minutes;

public class EsmGenerator2 {

    public static final Minutes BUFFER_MILLIS = Minutes.minutes(59);
    private SignalSchedule schedule;
    private DateTime periodStartDate;
    private ArrayList<DateTime> times;

    // divide time period evenly into blocks
    // pick "frequency" number of time blocks randomly
    // pick random times within each chosen block
    // skip times within 1 hour of other times
    public List<DateTime> generateForSchedule(DateTime startDate, SignalSchedule schedule) {
        this.schedule = schedule;
        this.periodStartDate = adjustStartDateToBeginningOfPeriod(startDate);
        times = new ArrayList<DateTime>();

        if (schedule.getEsmFrequency() == null || schedule.getEsmFrequency() == 0) {
            return times;
        }
        List<Integer> schedulableDays;
        switch (schedule.getEsmPeriodInDays()) {
        case SignalSchedule.ESM_PERIOD_DAY:
            if (!schedule.getEsmWeekends() && TimeUtil.isWeekend(periodStartDate)) {
                return times;
            } else {
                schedulableDays = Arrays.asList(1);
            }
            break;
        case SignalSchedule.ESM_PERIOD_WEEK:
            schedulableDays = getPeriodDaysForWeek();
            break;
        case SignalSchedule.ESM_PERIOD_MONTH:
            schedulableDays = getPeriodDaysForMonthOf(periodStartDate);
            break;
        default:
            throw new IllegalStateException("Cannot get here.");
        }

        Minutes dayLengthIntervalInMinutes = Minutes
                .minutesIn(new Interval(schedule.getEsmStartHour(), schedule.getEsmEndHour()));
        Minutes totalMinutesInPeriod = dayLengthIntervalInMinutes.multipliedBy(schedulableDays.size());
        Minutes sampleBlockTimeInMinutes = totalMinutesInPeriod.dividedBy(schedule.getEsmFrequency());
        Minutes timeoutInMinutes = Minutes.minutes(schedule.getMinimumBuffer());
        Random rand = new Random();
        for (int signal = 0; signal < schedule.getEsmFrequency(); signal++) {

            int candidateTimeInBlock;
            DateTime candidateTime;
            int periodAttempts = 1000;
            do {
                candidateTimeInBlock = rand.nextInt(sampleBlockTimeInMinutes.getMinutes());
                // map candidatePeriod and candidateTime back onto days of period
                // note, sometimes a candidate period will map across days in period
                // because start and end hours make for non-contiguous days
                int totalMinutesToAdd = sampleBlockTimeInMinutes.getMinutes() * signal + candidateTimeInBlock;
                int daysToAdd = totalMinutesToAdd / dayLengthIntervalInMinutes.getMinutes();
                int minutesToAdd = 0;
                if (totalMinutesToAdd <= dayLengthIntervalInMinutes.getMinutes()) { // within one day
                    minutesToAdd = totalMinutesToAdd;
                } else {
                    minutesToAdd = totalMinutesToAdd % dayLengthIntervalInMinutes.getMinutes();
                }

                DateTime plusDays = periodStartDate.plusDays(schedulableDays.get(daysToAdd) - 1);
                candidateTime = plusDays.withMillisOfDay(schedule.getEsmStartHour().intValue())
                        .plusMinutes(minutesToAdd);
                periodAttempts--;
            } while (periodAttempts > 0
                    && (!isMinimalBufferedDistanceFromOtherTimes(candidateTime, timeoutInMinutes)
                            || (!schedule.getEsmWeekends() && TimeUtil.isWeekend(candidateTime))));
            if (isMinimalBufferedDistanceFromOtherTimes(candidateTime, timeoutInMinutes)
                    && (schedule.getEsmWeekends() || !TimeUtil.isWeekend(candidateTime))) {
                times.add(candidateTime);
            }

        }
        return times;
    }

    private DateTime adjustStartDateToBeginningOfPeriod(DateTime startDate) {
        switch (schedule.getEsmPeriodInDays()) {
        case SignalSchedule.ESM_PERIOD_DAY:
            return startDate;
        case SignalSchedule.ESM_PERIOD_WEEK:
            return startDate.dayOfWeek().withMinimumValue();
        case SignalSchedule.ESM_PERIOD_MONTH:
            return startDate.dayOfMonth().withMinimumValue();
        default:
            throw new IllegalStateException("Cannot get here.");
        }
    }

    private List<Integer> getPeriodDaysForWeek() {
        List<Integer> periods;
        if (schedule.getEsmWeekends()) {
            periods = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
        } else {
            periods = Arrays.asList(1, 2, 3, 4, 5);
        }
        return periods;
    }

    private List<Integer> getPeriodDaysForMonthOf(DateTime startDate) {
        int dow = startDate.getDayOfWeek();
        int day = 1;
        int lastDayOfMonth = startDate.dayOfMonth().withMaximumValue().getDayOfMonth();
        List<Integer> validPeriods = new ArrayList<Integer>();
        while (day < lastDayOfMonth + 1) {
            if (schedule.getEsmWeekends() || !TimeUtil.isWeekend(dow)) {
                validPeriods.add(day);
            }
            dow++;
            if (dow == 8) {
                dow = 1;
            }
            day++;
        }
        return validPeriods;
    }

    private boolean isMinimalBufferedDistanceFromOtherTimes(DateTime plusMinutes, Minutes timeoutInMinutes) {
        for (DateTime time : times) {

            Minutes minutesBetween;
            if (time.isAfter(plusMinutes)) {
                minutesBetween = Minutes.minutesBetween(plusMinutes, time);
            } else {
                minutesBetween = Minutes.minutesBetween(time, plusMinutes);
            }

            if (minutesBetween.isLessThan(timeoutInMinutes)) {
                return false;
            }
        }
        return true;
    }

}