| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.commons.math4.genetics; |
| |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.commons.math4.exception.NumberIsTooSmallException; |
| |
| /** |
| * Stops after a fixed amount of time has elapsed. |
| * <p> |
| * The first time {@link #isSatisfied(Population)} is invoked, the end time of |
| * the evolution is determined based on the provided <code>maxTime</code> value. |
| * Once the elapsed time reaches the configured <code>maxTime</code> value, |
| * {@link #isSatisfied(Population)} returns true. |
| * |
| * @since 3.1 |
| */ |
| public class FixedElapsedTime implements StoppingCondition { |
| /** Maximum allowed time period (in nanoseconds). */ |
| private final long maxTimePeriod; |
| |
| /** The predetermined termination time (stopping condition). */ |
| private long endTime = -1; |
| |
| /** |
| * Create a new {@link FixedElapsedTime} instance. |
| * |
| * @param maxTime maximum number of seconds generations are allowed to evolve |
| * @throws NumberIsTooSmallException if the provided time is < 0 |
| */ |
| public FixedElapsedTime(final long maxTime) throws NumberIsTooSmallException { |
| this(maxTime, TimeUnit.SECONDS); |
| } |
| |
| /** |
| * Create a new {@link FixedElapsedTime} instance. |
| * |
| * @param maxTime maximum time generations are allowed to evolve |
| * @param unit {@link TimeUnit} of the maxTime argument |
| * @throws NumberIsTooSmallException if the provided time is < 0 |
| */ |
| public FixedElapsedTime(final long maxTime, final TimeUnit unit) throws NumberIsTooSmallException { |
| if (maxTime < 0) { |
| throw new NumberIsTooSmallException(maxTime, 0, true); |
| } |
| maxTimePeriod = unit.toNanos(maxTime); |
| } |
| |
| /** |
| * Determine whether or not the maximum allowed time has passed. |
| * The termination time is determined after the first generation. |
| * |
| * @param population ignored (no impact on result) |
| * @return <code>true</code> IFF the maximum allowed time period has elapsed |
| */ |
| @Override |
| public boolean isSatisfied(final Population population) { |
| if (endTime < 0) { |
| endTime = System.nanoTime() + maxTimePeriod; |
| } |
| |
| return System.nanoTime() >= endTime; |
| } |
| } |