/**
* Removes the least recently used elements if the cache size is greater than or equal to the
* maximum allowed size until the cache is at least 10% empty.
*/
protected synchronized void cullCache() {
// Check if a max cache size is defined.
if (maxCacheSize < 0) {
return;
}
// See if the cache is too big. If so, clean out cache until it's 10% free.
if (map.size() > maxCacheSize) {
// First, delete any old entries to see how much memory that frees.
deleteExpiredEntries();
// Next, delete the least recently used elements until 10% of the cache
// has been freed.
int desiredSize = (int) (maxCacheSize * .90);
for (int i = map.size(); i > desiredSize; i--) {
// Get the key and invoke the remove method on it.
if (remove(lastAccessedList.getLast().object, true) == null) {
LOGGER.warning(
"Error attempting to cullCache with remove("
+ lastAccessedList.getLast().object.toString()
+ ") - cacheObject not found in cache!");
lastAccessedList.getLast().remove();
}
}
}
}
public synchronized boolean containsKey(Object key) {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
return map.containsKey(key);
}
public synchronized Set<K> keySet() {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
return Collections.unmodifiableSet(map.keySet());
}
public synchronized Collection<V> values() {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
return Collections.unmodifiableCollection(
new AbstractCollection<V>() {
Collection<CacheObject<V>> values = map.values();
public Iterator<V> iterator() {
return new Iterator<V>() {
Iterator<CacheObject<V>> it = values.iterator();
public boolean hasNext() {
return it.hasNext();
}
public V next() {
return it.next().object;
}
public void remove() {
it.remove();
}
};
}
public int size() {
return values.size();
}
});
}
public synchronized boolean isEmpty() {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
return map.isEmpty();
}
public synchronized boolean containsValue(Object value) {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
//noinspection unchecked
@SuppressWarnings("unchecked")
CacheObject<V> cacheObject = new CacheObject<V>((V) value);
return map.containsValue(cacheObject);
}
public synchronized Set<Map.Entry<K, V>> entrySet() {
// Warning -- this method returns CacheObject instances and not Objects
// in the same form they were put into cache.
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
return new AbstractSet<Map.Entry<K, V>>() {
private final Set<Map.Entry<K, CacheObject<V>>> set = map.entrySet();
public Iterator<Entry<K, V>> iterator() {
return new Iterator<Entry<K, V>>() {
private final Iterator<Entry<K, CacheObject<V>>> it = set.iterator();
public boolean hasNext() {
return it.hasNext();
}
public Entry<K, V> next() {
Map.Entry<K, CacheObject<V>> entry = it.next();
return new AbstractMapEntry<K, V>(entry.getKey(), entry.getValue().object) {
@Override
public V setValue(V value) {
throw new UnsupportedOperationException("Cannot set");
}
};
}
public void remove() {
it.remove();
}
};
}
public int size() {
return set.size();
}
};
}
public synchronized V get(Object key) {
// First, clear all entries that have been in cache longer than the
// maximum defined age.
deleteExpiredEntries();
CacheObject<V> cacheObject = map.get(key);
if (cacheObject == null) {
// The object didn't exist in cache, so increment cache misses.
cacheMisses++;
return null;
}
// Remove the object from it's current place in the cache order list,
// and re-insert it at the front of the list.
cacheObject.lastAccessedListNode.remove();
lastAccessedList.addFirst(cacheObject.lastAccessedListNode);
// The object exists in cache, so increment cache hits. Also, increment
// the object's read count.
cacheHits++;
cacheObject.readCount++;
return cacheObject.object;
}
