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package oracle.toplink.essentials.internal.identitymaps;
import java.util.*;
/**
* <p><b>Purpose</b>: A FullIdentityMap holds all objects stored within it for the life of the application
* <p><b>Responsibilities</b>:<ul>
* <li> Guarantees identity
* <li> Holds all cached objects indefinetly.
* </ul>
* @since TOPLink/Java 1.0
*/
public class FullIdentityMap extends IdentityMap {
/** Hashtable of CacheKeys stored using their key */
protected Hashtable cacheKeys;
public FullIdentityMap(int size) {
super(size);
cacheKeys = new Hashtable(size);
}
/**
* INTERNAL:
* Clones itself.
*/
public Object clone() {
FullIdentityMap clone = (FullIdentityMap)super.clone();
clone.setCacheKeys(new Hashtable(getCacheKeys().size()));
for (Enumeration cacheKeysEnum = getCacheKeys().elements();
cacheKeysEnum.hasMoreElements();) {
CacheKey key = (CacheKey)((CacheKey)cacheKeysEnum.nextElement()).clone();
clone.getCacheKeys().put(key, key);
}
return clone;
}
/**
* INTERNAL:
* Used to print all the Locks in every identity map in this session.
* The output of this method will go to log passed in as a parameter.
*/
public void collectLocks(HashMap threadList) {
Iterator cacheKeyIterator = this.cacheKeys.values().iterator();
while (cacheKeyIterator.hasNext()) {
CacheKey cacheKey = (CacheKey)cacheKeyIterator.next();
if (cacheKey.isAcquired()) {
Thread activeThread = cacheKey.getMutex().getActiveThread();
Set set = (Set)threadList.get(activeThread);
if (set == null) {
set = new HashSet();
threadList.put(activeThread, set);
}
set.add(cacheKey);
}
}
}
/**
* Allow for the cache to be iterated on.
*/
public Enumeration elements() {
return new IdentityMapEnumeration(this);
}
/**
* Return the object indexed in the recevier at the cache key.
* If now object for the key exists, return null.
* @return a CacheKey for the primary key or null
*/
protected synchronized CacheKey getCacheKey(CacheKey searchKey) {
return (CacheKey)getCacheKeys().get(searchKey);
}
public Hashtable getCacheKeys() {
return cacheKeys;
}
/**
* Return the number of objects in the IdentityMap.
*/
public int getSize() {
return cacheKeys.size();
}
/**
* Return the number of actual objects of type myClass in the IdentityMap.
* Recurse = true will include subclasses of myClass in the count.
*/
public int getSize(Class myClass, boolean recurse) {
int i = 0;
Enumeration keys = getCacheKeys().keys();
while (keys.hasMoreElements()) {
CacheKey key = (CacheKey)keys.nextElement();
Object obj = key.getObject();
if (obj != null) {
if (recurse && myClass.isInstance(obj)) {
i++;
} else if (obj.getClass().equals(myClass)) {
i++;
}
}
}
return i;
}
/**
* Allow for the cache keys to be iterated on.
*/
public Enumeration keys() {
return new IdentityMapKeyEnumeration(this);
}
/**
* Store the object in the cache at its primary key.
* @param primaryKey is the primary key for the object.
* @param object is the domain object to cache.
* @param writeLockValue is the current write lock value of object, if null the version is ignored.
*/
public CacheKey put(Vector primaryKey, Object object, Object writeLockValue, long readTime) {
CacheKey cacheKey = getCacheKey(primaryKey);
// Find the cache key in the hashtable, reset it.
if (cacheKey != null) {
// The cache key has to be locked during the re-setting, keep other threads from accessing the object.
resetCacheKey(cacheKey, object, writeLockValue);
// Still must put the object to ensure the LRU caching.
put(cacheKey);
} else {
// Cache key not found, create a new one and put it into the hashtable.
cacheKey = createCacheKey(primaryKey, object, writeLockValue, readTime);
put(cacheKey);
}
return cacheKey;
}
/**
* Store the object in the cache with the cache key.
*/
protected void put(CacheKey cacheKey) {
//synchronized because subclasses may not sync around call
synchronized(this){
getCacheKeys().put(cacheKey, cacheKey);
}
cacheKey.setOwningMap(this);
}
/**
* Removes the CacheKey from the Hashtable.
* @return The object held within the CacheKey or null if no object cached for given primaryKey
*/
public Object remove(CacheKey cacheKey) {
if (cacheKey != null) {
//Cache key needs to be locked when removing from the Hashtable
cacheKey.acquire();
//remove opration from the hashtable has to be synchronized
synchronized (this) {
getCacheKeys().remove(cacheKey);
}
//Cache key needs to be released after removing from the Hashtable
cacheKey.release();
} else {
return null;
}
return cacheKey.getObject();
}
public void resetCacheKey(CacheKey key, Object object, Object writeLockValue) {
resetCacheKey(key, object, writeLockValue, 0);
}
public void resetCacheKey(CacheKey key, Object object, Object writeLockValue, long readTime) {
key.acquire();
key.setObject(object);
key.setWriteLockValue(writeLockValue);
key.setReadTime(readTime);
key.release();
}
protected void setCacheKeys(Hashtable cacheKeys) {
this.cacheKeys = cacheKeys;
}
}
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