1 files changed, 78 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/genetics/FixedElapsedTime.java b/src/main/java/org/apache/commons/math3/genetics/FixedElapsedTime.java
new file mode 100644
index 0000000..af63094
--- /dev/null
+++ b/src/main/java/org/apache/commons/math3/genetics/FixedElapsedTime.java
@@ -0,0 +1,78 @@
+/*
+ * 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.math3.genetics;
+
+import org.apache.commons.math3.exception.NumberIsTooSmallException;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * 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 &lt; 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 &lt; 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
+     */
+    public boolean isSatisfied(final Population population) {
+        if (endTime < 0) {
+            endTime = System.nanoTime() + maxTimePeriod;
+        }
+
+        return System.nanoTime() >= endTime;
+    }
+}