1 files changed, 71 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/genetics/FixedGenerationCount.java b/src/main/java/org/apache/commons/math3/genetics/FixedGenerationCount.java
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+++ b/src/main/java/org/apache/commons/math3/genetics/FixedGenerationCount.java
@@ -0,0 +1,71 @@
+/*
+ * 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;
+
+/**
+ * Stops after a fixed number of generations. Each time {@link #isSatisfied(Population)} is invoked,
+ * a generation counter is incremented. Once the counter reaches the configured <code>maxGenerations
+ * </code> value, {@link #isSatisfied(Population)} returns true.
+ *
+ * @since 2.0
+ */
+public class FixedGenerationCount implements StoppingCondition {
+    /** Number of generations that have passed */
+    private int numGenerations = 0;
+
+    /** Maximum number of generations (stopping criteria) */
+    private final int maxGenerations;
+
+    /**
+     * Create a new FixedGenerationCount instance.
+     *
+     * @param maxGenerations number of generations to evolve
+     * @throws NumberIsTooSmallException if the number of generations is &lt; 1
+     */
+    public FixedGenerationCount(final int maxGenerations) throws NumberIsTooSmallException {
+        if (maxGenerations <= 0) {
+            throw new NumberIsTooSmallException(maxGenerations, 1, true);
+        }
+        this.maxGenerations = maxGenerations;
+    }
+
+    /**
+     * Determine whether or not the given number of generations have passed. Increments the number
+     * of generations counter if the maximum has not been reached.
+     *
+     * @param population ignored (no impact on result)
+     * @return <code>true</code> IFF the maximum number of generations has been exceeded
+     */
+    public boolean isSatisfied(final Population population) {
+        if (this.numGenerations < this.maxGenerations) {
+            numGenerations++;
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Returns the number of generations that have already passed.
+     *
+     * @return the number of generations that have passed
+     */
+    public int getNumGenerations() {
+        return numGenerations;
+    }
+}