001    /*
002     *  Copyright 2009-2013 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.money;
017    
018    /**
019     * Provides a uniform interface to obtain a {@code BigMoney}.
020     * <p>
021     * When designing APIs, it is recommended to use {@code BigMoneyProvider}
022     * in method signatures where possible to allow the widest possible use of the method.
023     * Within Joda-Money, both {@code BigMoney} and {@code Money} implement
024     * the provider interface.
025     * <p>
026     * Implementations of {@code BigMoneyProvider} may be mutable.
027     * To minimise the risk of the value of the provider changing while processing,
028     * any method that takes a {@code BigMoneyProvider} as a parameter should convert
029     * it to a {@code BigMoney} immediately and use that directly from then on.
030     * The method {@link BigMoney#of(BigMoneyProvider)} performs the conversion
031     * safely with null checks and is recommended for this purpose.
032     * <p>
033     * This interface makes no guarantees about the immutability or
034     * thread-safety of implementations.
035     */
036    public interface BigMoneyProvider {
037    
038        /**
039         * Returns a {@code BigMoney} instance equivalent to the value of this object.
040         * <p>
041         * It is recommended that {@link BigMoney#of(BigMoneyProvider)} is used in
042         * preference to calling this method directly. It is also recommended that the
043         * converted {@code BigMoney} is cached in a local variable instead of
044         * performing the conversion multiple times.
045         * 
046         * @return the converted money instance, never null
047         * @throws RuntimeException if conversion is not possible
048         */
049        BigMoney toBigMoney();
050    
051    }