/*
 *  Copyright 2001-2013 Stephen Colebourne
 *
 *  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 org.joda.time;

import org.joda.time.format.DateTimeFormat;

Exception thrown when attempting to create an instant or date-time that cannot exist.
 Classes like DateTime only store valid date-times. One of the cases where validity is important is handling daylight savings time (DST). In many places DST is used, where the local clock moves forward by an hour in spring and back by an hour in autumn/fall. This means that in spring, there is a "gap" where a local time does not exist. 

This exception refers to this gap, and it means that your application tried to create
a date-time inside the gap - a time that did not exist.
Since Joda-Time objects must be valid, this is not allowed.

Possible solutions may be as follows:

Use LocalDateTime, as all local date-times are valid.

When converting a LocalDate to a DateTime, then use toDateTimeAsStartOfDay()
as this handles and manages any gaps.

When parsing, use parseLocalDateTime() if the string being parsed has no time-zone.
Author:
Stephen Colebourne
Since:
2.2/**
 * Exception thrown when attempting to create an instant or date-time that cannot exist.
 * <p>
 * Classes like {@code DateTime} only store valid date-times.
 * One of the cases where validity is important is handling daylight savings time (DST).
 * In many places DST is used, where the local clock moves forward by an hour in spring and back by an hour in autumn/fall.
 * This means that in spring, there is a "gap" where a local time does not exist.
 * <p>
 * This exception refers to this gap, and it means that your application tried to create
 * a date-time inside the gap - a time that did not exist.
 * Since Joda-Time objects must be valid, this is not allowed.
 * <p>
 * Possible solutions may be as follows:<br />
 * Use <code>LocalDateTime</code>, as all local date-times are valid.<br />
 * When converting a <code>LocalDate</code> to a <code>DateTime</code>, then use <code>toDateTimeAsStartOfDay()</code>
 * as this handles and manages any gaps.<br />
 * When parsing, use <code>parseLocalDateTime()</code> if the string being parsed has no time-zone.
 *
 * @author Stephen Colebourne
 * @since 2.2
 */
public class IllegalInstantException extends IllegalArgumentException {
    
    
Serialization lock. /** Serialization lock. */
    private static final long serialVersionUID = 2858712538216L;


    
Constructor.
Params:
message –  the message/**
     * Constructor.
     * 
     * @param message  the message
     */
    public IllegalInstantException(String message) {
        super(message);
    }

    
Constructor.
Params:
instantLocal –  the local instant
zoneId –  the time-zone ID, may be null/**
     * Constructor.
     * 
     * @param instantLocal  the local instant
     * @param zoneId  the time-zone ID, may be null
     */
    public IllegalInstantException(long instantLocal, String zoneId) {
        super(createMessage(instantLocal, zoneId));
    }

    private static String createMessage(long instantLocal, String zoneId) {
        String localDateTime = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS").print(new Instant(instantLocal));
        String zone = (zoneId != null ? " (" + zoneId + ")" : "");
        return "Illegal instant due to time zone offset transition (daylight savings time 'gap'): " + localDateTime + zone;
    }

    //-----------------------------------------------------------------------
    
Checks if the exception is, or has a cause, of IllegalInstantException. 
Params:
ex –  the exception to check
Returns:
true if an IllegalInstantException/**
     * Checks if the exception is, or has a cause, of {@code IllegalInstantException}.
     * 
     * @param ex  the exception to check
     * @return true if an {@code IllegalInstantException}
     */
    public static boolean isIllegalInstant(Throwable ex) {
        if (ex instanceof IllegalInstantException) {
            return true;
        }
        while (ex.getCause() != null && ex.getCause() != ex) {
            return isIllegalInstant(ex.getCause());
        }
        return false;
    }

}