/*
 *  Copyright 2001-2009 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.convert;

import org.joda.time.Chronology;
import org.joda.time.DateTimeUtils;
import org.joda.time.DateTimeZone;
import org.joda.time.ReadableInstant;
import org.joda.time.chrono.ISOChronology;

ReadableInstantConverter extracts milliseconds and chronology from a ReadableInstant.
Author:
Stephen Colebourne
Since:
1.0/**
 * ReadableInstantConverter extracts milliseconds and chronology from a ReadableInstant.
 *
 * @author Stephen Colebourne
 * @since 1.0
 */
class ReadableInstantConverter extends AbstractConverter
        implements InstantConverter, PartialConverter {

    
Singleton instance.
/**
     * Singleton instance.
     */
    static final ReadableInstantConverter INSTANCE = new ReadableInstantConverter();

    
Restricted constructor.
/**
     * Restricted constructor.
     */
    protected ReadableInstantConverter() {
        super();
    }

    //-----------------------------------------------------------------------
    
Gets the chronology, which is taken from the ReadableInstant.
If the chronology on the instant is null, the ISOChronology in the
specified time zone is used.
If the chronology on the instant is not in the specified zone, it is
adapted.
Params:
object –  the ReadableInstant to convert, must not be null
zone –  the specified zone to use, null means default zone
Returns:
the chronology, never null/**
     * Gets the chronology, which is taken from the ReadableInstant.
     * If the chronology on the instant is null, the ISOChronology in the
     * specified time zone is used.
     * If the chronology on the instant is not in the specified zone, it is
     * adapted.
     * 
     * @param object  the ReadableInstant to convert, must not be null
     * @param zone  the specified zone to use, null means default zone
     * @return the chronology, never null
     */
    public Chronology getChronology(Object object, DateTimeZone zone) {
        Chronology chrono = ((ReadableInstant) object).getChronology();
        if (chrono == null) {
            return ISOChronology.getInstance(zone);
        }
        DateTimeZone chronoZone = chrono.getZone();
        if (chronoZone != zone) {
            chrono = chrono.withZone(zone);
            if (chrono == null) {
                return ISOChronology.getInstance(zone);
            }
        }
        return chrono;
    }

    
Gets the chronology, which is taken from the ReadableInstant.

If the passed in chronology is non-null, it is used.
Otherwise the chronology from the instant is used.
Params:
object –  the ReadableInstant to convert, must not be null
chrono –  the chronology to use, null means use that from object
Returns:
the chronology, never null/**
     * Gets the chronology, which is taken from the ReadableInstant.
     * <p>
     * If the passed in chronology is non-null, it is used.
     * Otherwise the chronology from the instant is used.
     * 
     * @param object  the ReadableInstant to convert, must not be null
     * @param chrono  the chronology to use, null means use that from object
     * @return the chronology, never null
     */
    public Chronology getChronology(Object object, Chronology chrono) {
        if (chrono == null) {
            chrono = ((ReadableInstant) object).getChronology();
            chrono = DateTimeUtils.getChronology(chrono);
        }
        return chrono;
    }

    
Extracts the millis from an object of this converter's type.
Params:
object –  the ReadableInstant to convert, must not be null
chrono –  the non-null result of getChronology
Throws:
NullPointerException – if the object is null
ClassCastException – if the object is an invalid type
Returns:
the millisecond value/**
     * Extracts the millis from an object of this converter's type.
     * 
     * @param object  the ReadableInstant to convert, must not be null
     * @param chrono  the non-null result of getChronology
     * @return the millisecond value
     * @throws NullPointerException if the object is null
     * @throws ClassCastException if the object is an invalid type
     */
    public long getInstantMillis(Object object, Chronology chrono) {
        return ((ReadableInstant) object).getMillis();
    }

    //-----------------------------------------------------------------------
    
Returns ReadableInstant.class.
Returns:
ReadableInstant.class/**
     * Returns ReadableInstant.class.
     * 
     * @return ReadableInstant.class
     */
    public Class<?> getSupportedType() {
        return ReadableInstant.class;
    }

}