|
1
19 package org.apache.cayenne.cache;
20
21 import java.io.Serializable  ;
22 import java.util.Iterator ;
23 import java.util.List ;
24 import java.util.Map ;
25
26 import org.apache.cayenne.CayenneRuntimeException;
27 import org.apache.cayenne.query.QueryMetadata;
28 import org.apache.commons.collections.map.LRUMap;
29
30
37 public class MapQueryCache implements QueryCache, Serializable {
38
39 public static final int DEFAULT_CACHE_SIZE = 2000;
40
41 protected Map map;
42
43 public MapQueryCache() {
44 this(DEFAULT_CACHE_SIZE);
45 }
46
47 public MapQueryCache(int maxSize) {
48 this.map = new LRUMap(maxSize);
49 }
50
51 public List get(QueryMetadata metadata) {
52 String key = metadata.getCacheKey();
53 if (key == null) {
54 return null;
55 }
56
57 CacheEntry entry;
58 synchronized (this) {
59 entry = (CacheEntry) map.get(key);
60 }
61
62 return (entry != null) ? entry.list : null;
63 }
64
65
71 public List get(QueryMetadata metadata, QueryCacheEntryFactory factory) {
72 List result = get(metadata);
73 if (result == null) {
74 Object newObject = factory.createObject();
75
76 if (!(newObject instanceof List )) {
77 if (newObject == null) {
78 throw new CayenneRuntimeException("Null on cache rebuilding: "
79 + metadata.getCacheKey());
80 }
81 else {
82 throw new CayenneRuntimeException(
83 "Invalid query result, expected List, got "
84 + newObject.getClass().getName());
85 }
86 }
87
88 result = (List ) newObject;
89 put(metadata, result);
90 }
91
92 return result;
93 }
94
95 public void put(QueryMetadata metadata, List results) {
96 String key = metadata.getCacheKey();
97 if (key != null) {
98
99 CacheEntry entry = new CacheEntry();
100 entry.list = results;
101 entry.cacheGroups = metadata.getCacheGroups();
102
103 synchronized (this) {
104 map.put(key, entry);
105 }
106 }
107 }
108
109 public void remove(String key) {
110 if (key != null) {
111 synchronized (this) {
112 map.remove(key);
113 }
114 }
115 }
116
117 public void removeGroup(String groupKey) {
118 if (groupKey != null) {
119 synchronized (this) {
120 Iterator it = map.values().iterator();
121 while (it.hasNext()) {
122 CacheEntry entry = (CacheEntry) it.next();
123 if (entry.cacheGroups != null) {
124 for (int i = 0; i < entry.cacheGroups.length; i++) {
125
126 if (groupKey.equals(entry.cacheGroups[i])) {
127 it.remove();
128 break;
129 }
130 }
131 }
132 }
133 }
134 }
135 }
136
137 public void clear() {
138 synchronized (this) {
139 map.clear();
140 }
141 }
142
143 public int size() {
144 return map.size();
145 }
146
147 final class CacheEntry {
148
149 List list;
150 String [] cacheGroups;
151 }
152 }
153 |
Popular Tags |
Java API By Example, From Geeks To Geeks.