001    /*
002     *  Copyright 2001-2005 Stephen Colebourne
003     *
004     *  Licensed under the Apache License, Version 2.0 (the "License");
005     *  you may not use this file except in compliance with the License.
006     *  You may obtain a copy of the License at
007     *
008     *      http://www.apache.org/licenses/LICENSE-2.0
009     *
010     *  Unless required by applicable law or agreed to in writing, software
011     *  distributed under the License is distributed on an "AS IS" BASIS,
012     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     *  See the License for the specific language governing permissions and
014     *  limitations under the License.
015     */
016    package org.joda.time.convert;
017    
018    import org.joda.time.Chronology;
019    import org.joda.time.DateTimeZone;
020    
021    /**
022     * InstantConverter defines how an object is converted to milliseconds/chronology.
023     * <p>
024     * The two methods in this interface must be called in order, as the
025     * <code>getInstantMillis</code> method relies on the result of the
026     * <code>getChronology</code> method being passed in.
027     *
028     * @author Stephen Colebourne
029     * @since 1.0
030     */
031    public interface InstantConverter extends Converter {
032    
033        /**
034         * Extracts the chronology from an object of this converter's type
035         * where the time zone is specified.
036         * 
037         * @param object  the object to convert
038         * @param zone  the specified zone to use, null means default zone
039         * @return the chronology, never null
040         * @throws ClassCastException if the object is invalid
041         */
042        Chronology getChronology(Object object, DateTimeZone zone);
043    
044        /**
045         * Extracts the chronology from an object of this converter's type
046         * where the chronology may be specified.
047         * <p>
048         * If the chronology is non-null it should be used. If it is null, then the
049         * object should be queried, and if it has no chronology then ISO default is used.
050         * 
051         * @param object  the object to convert
052         * @param chrono  the chronology to use, null means use object
053         * @return the chronology, never null
054         * @throws ClassCastException if the object is invalid
055         */
056        Chronology getChronology(Object object, Chronology chrono);
057    
058        //-----------------------------------------------------------------------
059        /**
060         * Extracts the millis from an object of this converter's type.
061         * <p>
062         * The chronology passed in is the result of the call to <code>getChronology</code>.
063         * 
064         * @param object  the object to convert
065         * @param chrono  the chronology to use, which is the non-null result of getChronology()
066         * @return the millisecond instant
067         * @throws ClassCastException if the object is invalid
068         * @throws IllegalArgumentException if object conversion fails
069         */
070        long getInstantMillis(Object object, Chronology chrono);
071    
072    }