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package oracle.toplink.essentials.internal.identitymaps;
import java.io.*;
import java.util.Arrays;
import java.util.Vector;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.sessions.Record;
/**
* <p><b>Purpose</b>: Container class for storing objects in an IdentityMap.
* <p><b>Responsibilities</b>:<ul>
* <li> Hold key and object.
* <li> Maintain and update the current writeLockValue.
* </ul>
* @since TOPLink/Java 1.0
*/
public class CacheKey implements Serializable, Cloneable {
/** The key holds the vector of primary key values for the object. */
protected Vector key;
/** Calculated hash value for CacheKey from primary key values. */
protected int hash;
protected Object object;
//used to store a reference to the map this cachkey is in in cases where the
//cache key is to be removed, prevents us from having to track down the owning
//map
protected IdentityMap mapOwner;
/** The writeLock value is being held as an object so that it might contain a number or timestamp. */
protected Object writeLockValue;
/** The cached wrapper for the object, used in EJB. */
protected Object wrapper;
/** The cache key hold a reference to the concurrency manager to perform the cache key level locking. */
protected ConcurrencyManager mutex;
/** This is used for Document Preservation to cache the record that this object was built from */
protected Record record;
/** This attribute is the system time in milli seconds that the object was last refreshed on */
//CR #4365
// CR #2698903 - fix for the previous fix. No longer using millis.
protected long lastUpdatedQueryId;
/** Invalidation State can be used to indicate whether this cache key is considered valid */
protected int invalidationState = CHECK_INVALIDATION_POLICY;
/** The following constants are used for the invalidationState variable */
public static final int CHECK_INVALIDATION_POLICY = 0;
public static final int CACHE_KEY_INVALID = -1;
/** The read time stores the millisecond value of the last time the object help by
this cache key was confirmed as up to date. */
protected long readTime = 0;
public CacheKey(Vector primaryKeys) {
this.key = primaryKeys;
this.hash = computeHash(primaryKeys);
}
public CacheKey(Vector primaryKey, Object object, Object lockValue) {
this(primaryKey);
//bug4649617 use setter instead of this.object = object to avoid hard reference on object in subclasses
setObject(object);
this.writeLockValue = lockValue;
}
public CacheKey(Vector primaryKey, Object object, Object lockValue, long readTime) {
this(primaryKey, object, lockValue);
this.readTime = readTime;
}
/**
* Acquire the lock on the cachek key object.
*/
public void acquire() {
getMutex().acquire(false);
}
/**
* Acquire the lock on the cachek key object. For the merge process
* called with true from the merge process, if true then the refresh will not refresh the object
*/
public void acquire(boolean forMerge) {
getMutex().acquire(forMerge);
}
/**
* Acquire the lock on the cache key object. But only if the object has no lock on it
* Added for CR 2317
*/
public boolean acquireNoWait() {
return getMutex().acquireNoWait(false);
}
/**
* Acquire the lock on the cache key object. But only if the object has no lock on it
* Added for CR 2317
* called with true from the merge process, if true then the refresh will not refresh the object
*/
public boolean acquireNoWait(boolean forMerge) {
return getMutex().acquireNoWait(forMerge);
}
/**
* Acquire the deferred lcok.
*/
public void acquireDeferredLock() {
getMutex().acquireDeferredLock();
}
/**
* Check the read lock on the cachek key object.
* This can be called to ensure the cache key has a valid built object.
* It does not hold a lock, so the object could be refreshed afterwards.
*/
public void checkReadLock() {
getMutex().checkReadLock();
}
/**
* Acquire the read lock on the cachek key object.
*/
public void acquireReadLock() {
getMutex().acquireReadLock();
}
/**
* Acquire the read lock on the cache key object.
*/
public boolean acquireReadLockNoWait() {
return getMutex().acquireReadLockNoWait();
}
/**
* INTERNAL:
* Clones itself.
*/
public Object clone() {
Object object = null;
try {
object = super.clone();
} catch (Exception exception) {
throw new InternalError(exception.toString());
}
return object;
}
/**
* Compute a hash value for the CacheKey dependent upon the values of the primary key
* instead of the identity of the receiver.
* This method is intended for use by constructors only.
*/
protected int computeHash(Vector primaryKey) {
int computedHashValue = 0;
for (int index = 0; index < primaryKey.size(); index++) {
Object value = primaryKey.elementAt(index);
if (value != null) {
//gf bug 1193: fix to handle array hashcodes properly
if (value.getClass().isArray()) {
computedHashValue = computedHashValue ^ computeArrayHashCode(value);
} else {
computedHashValue = computedHashValue ^ (value.hashCode());
}
}
}
return computedHashValue;
}
/**
* Compute the hashcode for supported array types
* @param obj - an array
* @return hashCode value
*/
private int computeArrayHashCode(Object obj) {
if (obj.getClass() == ClassConstants.APBYTE) {
return Arrays.hashCode((byte []) obj);
} else if (obj.getClass() == ClassConstants.APCHAR) {
return Arrays.hashCode((char []) obj);
} else {
return Arrays.hashCode((Object []) obj);
}
}
/**
* Determine if the receiver is equal to anObject.
* If anObject is a CacheKey, do further comparison, otherwise, return false.
* @see CacheKey#equals(CacheKey)
*/
public boolean equals(Object object) {
if (object instanceof CacheKey) {
return equals((CacheKey)object);
}
return false;
}
/**
* Determine if the receiver is equal to key.
* Use an index compare, because it is much faster than enumerations.
*/
public boolean equals(CacheKey key) {
if (this == key) {
return true;
}
if (getKey().size() == key.getKey().size()) {
for (int index = 0; index < getKey().size(); index++) {
Object myValue = getKey().elementAt(index);
Object comparisionValue = key.getKey().elementAt(index);
if (myValue == null) {
if (comparisionValue != null) {
return false;
}
} else if (myValue.getClass().isArray()) {
//gf bug 1193: fix array comparison logic to exit if they don't match, and continue the loop if they do
if (((myValue.getClass() == ClassConstants.APBYTE) && (comparisionValue.getClass() == ClassConstants.APBYTE)) ) {
if (!Helper.compareByteArrays((byte[])myValue, (byte[])comparisionValue)){
return false;
}
} else if (((myValue.getClass() == ClassConstants.APCHAR) && (comparisionValue.getClass() == ClassConstants.APCHAR)) ) {
if (!Helper.compareCharArrays((char[])myValue, (char[])comparisionValue)){
return false;
}
} else {
if (!Helper.compareArrays((Object[])myValue, (Object[])comparisionValue)) {
return false;
}
}
} else {
if (!(myValue.equals(comparisionValue))) {
return false;
}
}
}
return true;
}
return false;
}
/**
* INTERNAL:
* This method returns the system time in millis seconds at which this object was last refreshed
* CR #4365
* CR #2698903 ... instead of using millis we will now use id's instead. Method
* renamed appropriately.
*/
public long getLastUpdatedQueryId() {
return this.lastUpdatedQueryId;
}
public Vector getKey() {
return key;
}
/**
* Return the concurrency manager.
*/
public synchronized ConcurrencyManager getMutex() {
if (mutex == null) {
mutex = new ConcurrencyManager(this);
}
return mutex;
}
public Object getObject() {
return object;
}
public IdentityMap getOwningMap(){
return this.mapOwner;
}
/**
* INTERNAL:
* Return the current value of the Read Time variable
*/
public long getReadTime() {
return readTime;
}
public Record getRecord() {
return record;
}
public Object getWrapper() {
return wrapper;
}
public Object getWriteLockValue() {
return writeLockValue;
}
/**
* Overrides hashCode() in Object to use the primaryKey's hashCode for storage in data structures.
*/
public int hashCode() {
return hash;
}
/**
* Return if the lock is acquired
*/
public boolean isAcquired() {
return getMutex().isAcquired();
}
/**
* INTERNAL:
* Return the value of the invalidationState Variable
* The return value will be a constant
* CHECK_INVALIDATION_POLICY - The Invalidation policy is must be checked for this cache key's sate
* CACHE_KEY_INVALID - This cache key has been labeled invalid.
*/
public int getInvalidationState() {
return invalidationState;
}
/**
* Release the lock on the cachek key object.
*/
public void release() {
getMutex().release();
}
/**
* Release the deferred lock
*/
public void releaseDeferredLock() {
getMutex().releaseDeferredLock();
}
/**
* Release the read lock on the cachek key object.
*/
public void releaseReadLock() {
getMutex().releaseReadLock();
}
/**
* INTERNAL:
* Set the value of the invalidationState Variable
* The possible values are from an enumeration of constants
* CHECK_INVALIDATION_POLICY - The invalidation policy is must be checked for this cache key's sate
* CACHE_KEY_INVALID - This cache key has been labeled invalid.
*/
public void setInvalidationState(int invalidationState) {
this.invalidationState = invalidationState;
}
/**
* INTERNAL:
* This method sets the system time in millis seconds at which this object was last refreshed
* CR #4365
* CR #2698903 ... instead of using millis we will now use ids instead. Method
* renamed appropriately.
*/
public void setLastUpdatedQueryId(long id) {
this.lastUpdatedQueryId = id;
}
public void setKey(Vector key) {
this.key = key;
this.hash = computeHash(key);
}
/**
* Set the concurrency manager.
*/
public void setMutex(ConcurrencyManager mutex) {
this.mutex = mutex;
}
public void setObject(Object object) {
this.object = object;
}
public void setOwningMap(IdentityMap map){
this.mapOwner = map;
}
/**
* INTERNAL:
* Set the read time of this cache key
*/
public void setReadTime(long readTime) {
this.readTime = readTime;
invalidationState = CHECK_INVALIDATION_POLICY;
}
public void setRecord(Record newRecord) {
this.record = newRecord;
}
public void setWrapper(Object wrapper) {
this.wrapper = wrapper;
}
public void setWriteLockValue(Object writeLockValue) {
this.writeLockValue = writeLockValue;
}
public String toString() {
int hashCode = 0;
if (getObject() != null) {
hashCode = getObject().hashCode();
}
return "[" + getKey() + ": " + hashCode + ": " + getWriteLockValue() + ": " + getReadTime() + ": " + getObject() + "]";
}
/**
* Notifies that cache key that it has been accessed.
* Allows the LRU sub-cache to be maintained.
*/
public void updateAccess() {
// Nothing required by default.
}
}
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