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java/org/apache/tomcat/dbcp/pool2/impl/EvictionPolicy.java

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+/*
+ * 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.tomcat.dbcp.pool2.impl;
+
+import org.apache.tomcat.dbcp.pool2.PooledObject;
+
+/**
+ * To provide a custom eviction policy (i.e. something other than {@link
+ * DefaultEvictionPolicy} for a pool, users must provide an implementation of
+ * this interface that provides the required eviction policy.
+ *
+ * @param <T> the type of objects in the pool
+ *
+ * @since 2.0
+ */
+public interface EvictionPolicy<T> {
+
+    /**
+     * This method is called to test if an idle object in the pool should be
+     * evicted or not.
+     *
+     * @param config    The pool configuration settings related to eviction
+     * @param underTest The pooled object being tested for eviction
+     * @param idleCount The current number of idle objects in the pool including
+     *                      the object under test
+     * @return <code>true</code> if the object should be evicted, otherwise
+     *             <code>false</code>
+     */
+    boolean evict(EvictionConfig config, PooledObject<T> underTest, int idleCount);
+}