001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.rng;
018
019/**
020 * Applies to generators whose internal state can be saved and restored.
021 *
022 * @since 1.0
023 */
024public interface RestorableUniformRandomProvider extends UniformRandomProvider {
025    /**
026     * Saves the state of a generator.
027     *
028     * @return the current state of this instance. It is a value that can
029     * subsequently be passed to the {@link #restoreState(RandomProviderState)
030     * restore} method.
031     * @throws UnsupportedOperationException if the underlying source of
032     * randomness does not support this functionality.
033     */
034    RandomProviderState saveState();
035
036    /**
037     * Restores the state of a generator.
038     *
039     * @param state State which this instance will be set to.
040     * This parameter would usually have been obtained by a call to
041     * {@link #saveState() saveState} performed either on the same
042     * object as this one, or an object of the exact same class.
043     * @throws UnsupportedOperationException if the underlying source of
044     * randomness does not support this functionality.
045     * @throws IllegalArgumentException if it was detected that the
046     * {@code state} argument is incompatible with this instance.
047     */
048    void restoreState(RandomProviderState state);
049}