| /** |
| * 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.pdfbox.jbig2.util.cache; |
| |
| import java.lang.ref.SoftReference; |
| import java.util.HashMap; |
| |
| public class SoftReferenceCache implements Cache { |
| |
| private HashMap<Object, SoftReference<?>> cache = new HashMap<Object, SoftReference<?>>(); |
| |
| public Object put(Object key, Object value, int sizeEstimate) { |
| SoftReference<Object> softReference = new SoftReference<Object>(value); |
| SoftReference<?> oldValue = cache.put(key, softReference); |
| return getValueNullSafe(oldValue); |
| } |
| |
| public Object get(Object key) { |
| SoftReference<?> softReference = cache.get(key); |
| return getValueNullSafe(softReference); |
| } |
| |
| public void clear() { |
| cache.clear(); |
| } |
| |
| public Object remove(Object key) { |
| SoftReference<?> removedObj = cache.remove(key); |
| return getValueNullSafe(removedObj); |
| } |
| |
| private Object getValueNullSafe(SoftReference<?> softReference) { |
| return softReference == null ? null : softReference.get(); |
| } |
| } |