| /* |
| * 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.openjpa.lib.util; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.lang.ref.Reference; |
| |
| /** |
| * Map in which the key, value, or both may be weak/soft references. |
| * |
| * @author Abe White |
| * @since 0.4.0 |
| */ |
| public class ReferenceHashMap |
| extends org.apache.commons.collections.map.ReferenceMap |
| implements ReferenceMap, SizedMap { |
| |
| private int _maxSize = Integer.MAX_VALUE; |
| |
| public ReferenceHashMap(int keyType, int valueType) { |
| super(toReferenceConstant(keyType), toReferenceConstant(valueType)); |
| } |
| |
| public ReferenceHashMap(int keyType, int valueType, int capacity, |
| float loadFactor) { |
| super(toReferenceConstant(keyType), toReferenceConstant(valueType), |
| capacity, loadFactor); |
| } |
| |
| /** |
| * Concver our reference constants to Apache's. |
| */ |
| private static int toReferenceConstant(int type) { |
| switch (type) { |
| case ReferenceMap.HARD: |
| return org.apache.commons.collections.map.ReferenceMap. HARD; |
| case ReferenceMap.SOFT: |
| return org.apache.commons.collections.map.ReferenceMap. SOFT; |
| default: |
| return org.apache.commons.collections.map.ReferenceMap. WEAK; |
| } |
| } |
| |
| public int getMaxSize() { |
| return _maxSize; |
| } |
| |
| public void setMaxSize(int maxSize) { |
| _maxSize = (maxSize < 0) ? Integer.MAX_VALUE : maxSize; |
| if (_maxSize != Integer.MAX_VALUE) |
| removeOverflow(_maxSize); |
| } |
| |
| public boolean isFull() { |
| return size() >= _maxSize; |
| } |
| |
| public void overflowRemoved(Object key, Object value) { |
| } |
| |
| public void valueExpired(Object key) { |
| } |
| |
| public void keyExpired(Object value) { |
| } |
| |
| public void removeExpired() { |
| purge(); |
| } |
| |
| /** |
| * Remove any entries over max size. |
| */ |
| private void removeOverflow(int maxSize) { |
| Object key; |
| while (size() > maxSize) { |
| key = keySet().iterator().next(); |
| overflowRemoved(key, remove(key)); |
| } |
| } |
| |
| protected void addMapping(int hashIndex, int hashCode, Object key, |
| Object value) { |
| if (_maxSize != Integer.MAX_VALUE) |
| removeOverflow(_maxSize - 1); |
| super.addMapping(hashIndex, hashCode, key, value); |
| } |
| |
| protected HashEntry createEntry(HashEntry next, int hashCode, Object key, |
| Object value) { |
| return new AccessibleEntry(this, next, hashCode, key, value); |
| } |
| |
| protected void purge(Reference ref) { |
| // the logic for this method is taken from the original purge method |
| // we're overriding, with added logic to track the expired key/value |
| int index = hashIndex(ref.hashCode(), data.length); |
| AccessibleEntry entry = (AccessibleEntry) data[index]; |
| AccessibleEntry prev = null; |
| Object key = null, value = null; |
| while (entry != null) { |
| if (purge(entry, ref)) { |
| if (isHard(keyType)) |
| key = entry.key(); |
| else if (isHard(valueType)) |
| value = entry.value(); |
| |
| if (prev == null) |
| data[index] = entry.nextEntry(); |
| else |
| prev.setNextEntry(entry.nextEntry()); |
| size--; |
| break; |
| } |
| prev = entry; |
| entry = entry.nextEntry(); |
| } |
| |
| if (key != null) |
| valueExpired(key); |
| else if (value != null) |
| keyExpired(value); |
| } |
| |
| /** |
| * See the code for <code>ReferenceMap.ReferenceEntry.purge</code>. |
| */ |
| private boolean purge(AccessibleEntry entry, Reference ref) { |
| boolean match = (!isHard(keyType) && entry.key() == ref) |
| || (!isHard(valueType) && entry.value() == ref); |
| if (match) { |
| if (!isHard(keyType)) |
| ((Reference) entry.key()).clear(); |
| if (!isHard(valueType)) |
| ((Reference) entry.value()).clear(); |
| else if (purgeValues) |
| entry.nullValue(); |
| } |
| return match; |
| } |
| |
| private static boolean isHard(int type) { |
| return type == org.apache.commons.collections.map. ReferenceMap.HARD; |
| } |
| |
| protected void doWriteObject(ObjectOutputStream out) throws IOException { |
| out.writeInt(_maxSize); |
| super.doWriteObject(out); |
| } |
| |
| protected void doReadObject(ObjectInputStream in) |
| throws ClassNotFoundException, IOException { |
| _maxSize = in.readInt(); |
| super.doReadObject(in); |
| } |
| |
| /** |
| * Extension of the base entry type that allows our outer class to access |
| * protected state. |
| */ |
| private static class AccessibleEntry extends ReferenceEntry { |
| |
| public AccessibleEntry(org.apache.commons.collections.map. |
| AbstractReferenceMap map, HashEntry next, |
| int hashCode, Object key, Object value) { |
| super(map, next, hashCode, key, value); |
| } |
| |
| public Object key() { |
| return key; |
| } |
| |
| public Object value() { |
| return value; |
| } |
| |
| public void nullValue() { |
| value = null; |
| } |
| |
| public AccessibleEntry nextEntry() { |
| return (AccessibleEntry) next; |
| } |
| |
| public void setNextEntry(AccessibleEntry next) { |
| this.next = next; |
| } |
| } |
| } |