Java Timestamp roundToHour(Timestamp arg)

Description

rounds the input value to the nearest whole hour

License

Open Source License

Parameter

Parameter	Description
arg	input Timestamp

Return

the input value to the nearest whole hour

Declaration

public static Timestamp roundToHour(Timestamp arg) 

Method Source Code

//package com.java2s;
/*/*from ww w .  j av a  2 s. c o  m*/
 * @(#)TimeUtils.java   0.51 1999/07/14
 *
 * Copyright (c) 2004, Pat Farrell, All rights reserved.
 * based on work Copyright (c) 2000, OneBigCD, Inc.  All rights reserved.
 * Copyright (C) 2011 Patrick Farrell   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. * 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.
 * 
 * It is abstract because all functions are static
 */

import java.sql.Timestamp;

import java.util.Calendar;

import java.util.GregorianCalendar;

import java.util.TimeZone;

public class Main {
    /** constant for UTC */
    public static final TimeZone utcTZ = TimeZone.getTimeZone("UTC");

    /**
     * rounds the input value to the nearest whole hour
     * @param arg input Timestamp
     * @return the input value to the nearest whole hour
     */
    public static Timestamp roundToHour(Timestamp arg) {
        return new Timestamp(roundToSecs(arg, 60 * 60));
    }

    /**
     * internal routine to convert timestamp to number of milliseconds rounded
     * @param arg incoming timestamp
     * @param seconds seconds to round to (1 gives seconds, 60 gives minues, etc.)
     * @return milliseconds rounded.
     */
    private static long roundToSecs(Timestamp arg, int seconds) {
        long restored = 0;
        if (arg != null) {
            Timestamp odark = startOfDay(arg);
            long delta = arg.getTime() - odark.getTime();
            long rounded = Math.round((delta) / (1000.0 * seconds));
            restored = odark.getTime() + rounded * (1000 * seconds);
        }
        return restored;
    }

    /** 
     * covert Date to start of day, 00:00:00 leaving date part
     * untouched
     * @param dd a date to use
     * @return  same date, first minute of first second
     */
    public static java.sql.Date startOfDay(java.sql.Date dd) {
        Calendar cal = GregorianCalendar.getInstance(utcTZ);
        if (dd != null) {
            cal.setTime(dd);
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            cal.set(Calendar.MILLISECOND, 0);
        }
        java.sql.Date rval = new java.sql.Date(cal.getTime().getTime());
        return rval;
    }

    /** 
     * covert Timestamp to start of day, 00:00:00 leaving date part
     * untouched
     * @param dd a date to use
     * @return  same date, first minute of first second
     */
    public static java.sql.Timestamp startOfDay(java.sql.Timestamp dd) {
        Calendar cal = GregorianCalendar.getInstance(utcTZ);
        if (dd != null) {
            cal.setTime(dd);
            cal.set(Calendar.HOUR_OF_DAY, 0);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            cal.set(Calendar.MILLISECOND, 0);
        }
        java.sql.Timestamp rval = new java.sql.Timestamp(cal.getTime().getTime());
        return rval;
    }

    /** 
     * covert calendar to start of day, 00:00:00 leaving date part
     * untouched
     * @param cal a calendar to use
     * @return  same date, last minute of last second
     */
    public static Calendar startOfDay(Calendar cal) {
        Calendar rval = (Calendar) cal.clone();
        rval.set(Calendar.HOUR_OF_DAY, 0);
        rval.set(Calendar.MINUTE, 0);
        rval.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND, 0);
        cal.getTimeInMillis();
        return rval;
    }
}

Related

1. readTimestamp(ByteBuffer logBuf)
2. readTimestamp(DataInput in)
3. readTimestamp(ObjectInput in, long nullFlag)
4. removeTime(Timestamp ts)
5. resetHourMinuteSecond(Timestamp timestamp, int hour, int minute, int second)
6. roundToSecond(Timestamp t)
7. safeTimestamp(Date value)
8. setTimestamp(byte[] ba, int offset, Timestamp val)
9. setTimestamp(int index, Timestamp t, PreparedStatement stmt)