1 package org.apache.commons.jcs3.engine.memory.util; 2 3 /* 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 22 import java.lang.ref.SoftReference; 23 24 import org.apache.commons.jcs3.engine.behavior.ICacheElement; 25 26 /** 27 * This wrapper is needed for double linked lists. 28 */ 29 public class SoftReferenceElementDescriptor<K, V> 30 extends MemoryElementDescriptor<K, V> 31 { 32 /** Don't change */ 33 private static final long serialVersionUID = -1905161209035522460L; 34 35 /** The CacheElement wrapped by this descriptor */ 36 private transient final SoftReference<ICacheElement<K, V>> srce; 37 38 /** 39 * Constructs a usable MemoryElementDescriptor. 40 * <p> 41 * @param ce 42 */ 43 public SoftReferenceElementDescriptor( final ICacheElement<K, V> ce ) 44 { 45 super( null ); 46 this.srce = new SoftReference<>(ce); 47 } 48 49 /** 50 * @return the ce 51 */ 52 @Override 53 public ICacheElement<K, V> getCacheElement() 54 { 55 if (srce != null) 56 { 57 return srce.get(); 58 } 59 60 return null; 61 } 62 }