/*
* Copyright 2005 Ralf Joachim, Gregory Bock, Werner Guttmann
*
* Licensed 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.castor.persist;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.castor.core.util.IdentityMap;
import org.castor.core.util.IdentitySet;
import org.castor.core.util.Messages;
import org.castor.persist.proxy.LazyCGLIB;
import org.exolab.castor.jdo.PersistenceException;
import org.exolab.castor.persist.ClassMolder;
import org.exolab.castor.persist.LockEngine;
import org.exolab.castor.persist.OID;
import org.exolab.castor.persist.spi.Identity;
/**
* A transaction records all objects accessed during the lifetime
* of the transaction in this record (queries and created).
*
* This information, stored on a per-object basis within the
* ObjectTracker, covers the database engine used
* to persist the object, the object's OID, the object itself, and
* whether the object has been deleted in this transaction,
* created in this transaction.
*
* Sidenote: Objects identified as read only are not updated
* when the transaction commits.
*
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @author <a href="mailto:werner DOT guttmann AT gmx DOT net">Werner Guttmann</a>
* @author <a href="mailto:gblock AT ctoforaday DOT COM">Gregory Block</a>
* @version $Revision$ $Date: 2006-04-29 09:15:50 -0600 (Sat, 29 Apr 2006) $
* @since 0.9.9
*/
public final class ObjectTracker {
//--------------------------------------------------------------------------
/** Map of Object->ClassMolder. */
private final Map _objectToMolder = new IdentityMap();
/** Map of Engine -> OID -> Object. */
private final Map _engineToOIDToObject = new HashMap();
/** Map of Object->OID. */
private final Map _objectToOID = new IdentityMap();
/** Set of all objects marked 'deleted'. */
private final Map _deletedMap = new IdentityMap();
/** Set of all objects marked 'creating'. */
private final Map _creatingMap = new IdentityMap();
/** Set of all objects marked 'created'. */
private final Set _createdSet = new IdentitySet();
/** Set of all objects for which we need to update persistence. */
private final Set _updatePersistNeededSet = new IdentitySet();
/** Set of all objects for which we need to update cache. */
private final Set _updateCacheNeededSet = new IdentitySet();
/** Set of all objects marked read only in this transaction. */
private final Set _readOnlySet = new IdentitySet();
/** Set of all objects marked read-write in this transaction. */
private final Set _readWriteSet = new IdentitySet();
/** Operation counter of ObjectTracker. */
private long _operation = Long.MIN_VALUE;
//--------------------------------------------------------------------------
/**
* Retrieve the object for a given OID.
*
* @param engine Lock engine mapped to oid
* @param oid Object id specified
* @param allowReadOnly Allow (or ignore, if false) read-only objects to be returned.
* @return The object associated with this oid.
*/
public Object getObjectForOID(final LockEngine engine,
final OID oid,
final boolean allowReadOnly) {
Map oidToObject = (Map) _engineToOIDToObject.get(engine);
if (oidToObject != null) {
Object found = oidToObject.get(oid);
if (!allowReadOnly) {
if (_readOnlySet.contains(found)) {
return null;
}
}
return found;
}
// We don't know about this engine in this transaction.
// Hence, to us, there is no mapping. Yet.
return null;
}
/**
* Returns true if the specified object is tracked as a read-write object.
* @param object Object instance for which it should be determined whether
* it's tracked as read-write object
* @return True if the specified object is tracked as a read-write object
*/
public boolean isReadWrite(final Object object) {
Object aObject = supportCGLibObject(object);
return (_readWriteSet.contains(aObject));
}
public void unmarkAllDeleted() {
_operation++;
_deletedMap.clear();
}
/**
* Reset ObjectTracker's state.
*/
public void clear() {
_operation++;
_createdSet.clear();
_creatingMap.clear();
_deletedMap.clear();
_engineToOIDToObject.clear();
_objectToMolder.clear();
_objectToOID.clear();
_readOnlySet.clear();
_readWriteSet.clear();
_updateCacheNeededSet.clear();
_updatePersistNeededSet.clear();
}
/**
* Returns true if the cache needs to be updated for the given object.
*
* @param object An object instance
* @return true if the cache needs to be updated; false, otherwise.
*/
public boolean isUpdateCacheNeeded(final Object object) {
Object aObject = supportCGLibObject(object);
return _updateCacheNeededSet.contains(aObject);
}
/**
* Returns true if the given object needs to be written to the persistence store.
*
* @param object An object instance
* @return true if the object needs to be written to the persistence store
*/
public boolean isUpdatePersistNeeded(final Object object) {
Object aObject = supportCGLibObject(object);
return _updatePersistNeededSet.contains(aObject);
}
public void markUpdateCacheNeeded(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
if (!isTracking(aObject)) {
return;
}
_updateCacheNeededSet.add(aObject);
}
public void unmarkUpdateCacheNeeded(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
_updateCacheNeededSet.remove(aObject);
}
public Collection getObjectsWithUpdateCacheNeededState() {
return new ArrayList(_updateCacheNeededSet);
}
public void markUpdatePersistNeeded(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
if (!isTracking(aObject)) {
return;
}
_updatePersistNeededSet.add(aObject);
// updatePersistNeeded implies updateCacheNeeded (from comment in persist())
_updateCacheNeededSet.add(aObject);
}
public void unmarkUpdatePersistNeeded(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
_updatePersistNeededSet.remove(aObject);
}
public void markCreating(final Object object) throws PersistenceException {
_operation++;
Object aObject = supportCGLibObject(object);
if (!isTracking(aObject)) {
return;
}
if (_createdSet.contains(aObject)) {
throw new PersistenceException("Invalid state change; can't mark something "
+ " creating which is already marked created.");
}
_creatingMap.put(aObject, new Long(_operation));
}
public void markCreated(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
if (!isTracking(aObject)) {
return;
}
_createdSet.add(aObject);
_creatingMap.remove(aObject);
}
public void markDeleted(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
if (!isTracking(aObject)) {
return;
}
_deletedMap.put(aObject, new Long(_operation));
}
public void unmarkDeleted(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
_deletedMap.remove(aObject);
}
/**
* Determine whether an object is being tracked within this tracking manager.
* @param object The object for which it should be determined whether it is tracked.
* @return True if the object specified is tracked; false otherwise
*/
public boolean isTracking(final Object object) {
Object aObject = supportCGLibObject(object);
return _objectToOID.containsKey(aObject);
}
/**
* Record changes to an OID by re-tracking the OID information. When an object's
* OID can change, ensure that the object is retracked.
*
* @param obj The object to record a tracking change for.
* @param engine The engine which is responsible for the old and new OID
* @param oldoid The old oid.
* @param newoid The new oid.
*/
public void trackOIDChange(final Object obj,
final LockEngine engine,
final OID oldoid,
final OID newoid) {
_operation++;
Object object = supportCGLibObject(obj);
removeOIDForObject(engine, oldoid);
setOIDForObject(object, engine, newoid);
}
/**
* For a given lockengine and OID, set the object in the maps. Note that an OID
* can only be accessed via the LockManager which manages it.
* @param obj The object to track
* @param engine The engine to which the OID belongs
* @param oid The OID of the object to track
*/
public void setOIDForObject(final Object obj,
final LockEngine engine,
final OID oid) {
_operation++;
Object object = supportCGLibObject(obj);
// Remove any current mapping.
removeOIDForObject(engine, oid);
// Now add it in.
Map oidToObject = (Map) _engineToOIDToObject.get(engine);
if (oidToObject == null) {
oidToObject = new HashMap();
_engineToOIDToObject.put(engine, oidToObject);
}
oidToObject.put(oid, obj);
// Add the reversal.
_objectToOID.put(object, oid);
}
/**
* For a given lockengine and OID, remove references to an object in the maps.
* This eliminates both the engine->oid->object and the object->oid.
* @param engine The engine to stop tracking the OID for
* @param oid The oid of the object to stop tracking on.
*/
public void removeOIDForObject(final LockEngine engine, final OID oid) {
_operation++;
Object found = null;
Map oidToObject = (Map) _engineToOIDToObject.get(engine);
if (oidToObject != null) {
found = oidToObject.get(oid);
oidToObject.remove(oid);
}
if (found != null) {
_objectToOID.remove(found);
}
}
public boolean isCreating(final Object o) {
Object object = supportCGLibObject(o);
return _creatingMap.containsKey(object);
}
public boolean isCreated(final Object o) {
Object object = supportCGLibObject(o);
return _createdSet.contains(object);
}
public boolean isDeleted(final Object o) {
Object object = supportCGLibObject(o);
return _deletedMap.containsKey(object);
}
/**
* Retrieve the ClassMolder associated with a specific object.
* @param o Object instance the associated ClassMolder should be retrieved.
* @return The ClassMolder instance associated with the Object instance specified.
*/
public ClassMolder getMolderForObject(final Object o) {
Object object = supportCGLibObject(o);
return (ClassMolder) _objectToMolder.get(object);
}
private void setMolderForObject(final Object obj, final ClassMolder molder) {
_operation++;
Object object = supportCGLibObject(obj);
// remove if exists
removeMolderForObject(object);
// Update objectToMolder (handles both new and pre-existing mappings)
_objectToMolder.put(object, molder);
}
private void removeMolderForObject(final Object obj) {
_operation++;
Object object = supportCGLibObject(obj);
_objectToMolder.remove(object);
}
/**
* Retrieve the list of all read-write objects being tracked.
* @return List of all read-write objects being currently tracked.
*/
public Collection getReadWriteObjects() {
ArrayList returnedList = new ArrayList(_readWriteSet);
return returnedList;
}
/**
* Retrieve the list of all read-only objects being tracked.
* @return List of all read-only objects being currently tracked
*/
public Collection getReadOnlyObjects() {
ArrayList returnedList = new ArrayList(_readOnlySet);
return returnedList;
}
/**
* Retrieve the list of 'creating' objects (to be created), sorted in the
* order they should be created.
* @return List of objects to be created, sorted in the order they should
* be created.
*/
public Collection getObjectsWithCreatingStateSortedByLowestMolderPriority() {
ArrayList entryList = new ArrayList(_creatingMap.entrySet());
Collections.sort(entryList, new ObjectMolderPriorityComparator(this, false));
ArrayList returnedList = new ArrayList(entryList.size());
for (int i = 0; i < entryList.size(); i++) {
returnedList.add(((Map.Entry) entryList.get(i)).getKey());
}
return returnedList;
}
/**
* Retrieve the list of 'deleted' objects, sorted in the order they should be
* deleted.
* @return List of 'deleted' objects, sorted in the order they should be
* deleted.
*/
public Collection getObjectsWithDeletedStateSortedByHighestMolderPriority() {
ArrayList entryList = new ArrayList(_deletedMap.entrySet());
Collections.sort(entryList, new ObjectMolderPriorityComparator(this, true));
ArrayList returnedList = new ArrayList(entryList.size());
for (int i = 0; i < entryList.size(); i++) {
returnedList.add(((Map.Entry) entryList.get(i)).getKey());
}
return returnedList;
}
public void trackObject(
final ClassMolder molder,
final OID oid,
final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
setMolderForObject(aObject, molder);
setOIDForObject(aObject, molder.getLockEngine(), oid);
_readWriteSet.add(aObject);
}
public void untrackObject(final Object object) {
_operation++;
Object aObject = supportCGLibObject(object);
// Grab any lockengine/OID information for removal of the nested
// engine-oid-object maps.
LockEngine engine = getMolderForObject(aObject).getLockEngine();
OID oid = getOIDForObject(aObject);
removeMolderForObject(aObject);
removeOIDForObject(engine, oid);
_deletedMap.remove(aObject);
_creatingMap.remove(aObject);
_createdSet.remove(aObject);
_updatePersistNeededSet.remove(aObject);
_updateCacheNeededSet.remove(aObject);
_readOnlySet.remove(aObject);
_readWriteSet.remove(aObject);
}
public OID getOIDForObject(final Object o) {
Object object = supportCGLibObject(o);
return (OID) _objectToOID.get(object);
}
public boolean isReadOnly(final Object o) {
Object object = supportCGLibObject(o);
return (_readOnlySet.contains(object));
}
public void markReadOnly(final Object o) {
_operation++;
Object object = supportCGLibObject(o);
if (!isTracking(object)) {
throw new IllegalStateException(Messages.format("persist.internal",
"Attempt to make read-only object that is not in transaction"));
}
// Add it to our list of read only objects.
_readOnlySet.add(object);
_readWriteSet.remove(object);
}
public void unmarkReadOnly(final Object o) {
_operation++;
Object object = supportCGLibObject(o);
if (!isTracking(object)) {
throw new IllegalStateException(Messages.format("persist.internal",
"Attempt to make read-write object that is not in transaction"));
}
// Add it to our list of read only objects.
_readWriteSet.add(object);
_readOnlySet.remove(object);
}
public int readOnlySize() {
return _readOnlySet.size();
}
public int readWriteSize() {
return _readWriteSet.size();
}
/**
* "Transform" an object provided as a LazyCGLib into a 'natural' object within
* the transaction, undecorated. This allows us to find the true object associated
* with a decorated object in the transaction.
*
* We do this by asking the decorated object for enough information to re-generate
* its proper OID; we then go looking for that OID in the system to find the object
* in the transaction.
*
* @param object
* @return
*/
private Object supportCGLibObject(final Object object) {
if (object instanceof LazyCGLIB) {
LazyCGLIB cgObject = (LazyCGLIB) object;
// TODO [WG] We still might have an option for some serious optimization
// here if the instance has not been materialized yet.
Identity identity = cgObject.interceptedIdentity();
ClassMolder molder = cgObject.interceptedClassMolder();
LockEngine engine = molder.getLockEngine();
// Get the OID we're looking for.
OID oid = new OID(molder, identity);
// Retrieve the object for this OID; returns null if there ain't such object
return getObjectForOID(engine, oid, true);
}
return object;
}
public String allObjectStates() {
StringBuffer sb = new StringBuffer();
Iterator it = _objectToOID.keySet().iterator();
while (it.hasNext()) {
sb.append(objectStateToString(it.next()));
sb.append("\n");
}
return sb.toString();
}
/**
* Returns the object's state.
* @param obj Object for which its state should be output.
* @return The state of the object specified
*/
public String objectStateToString(final Object obj) {
StringBuffer sb = new StringBuffer();
sb.append(getOIDForObject(obj));
sb.append('\t');
sb.append("deleted: ");
sb.append(_deletedMap.containsKey(obj));
sb.append('\t'); sb.append("creating: ");
sb.append(_creatingMap.containsKey(obj));
sb.append('\t');
sb.append("created: ");
sb.append(_createdSet.contains(obj));
return sb.toString();
}
//--------------------------------------------------------------------------
private static final class ObjectMolderPriorityComparator implements Comparator {
private ObjectTracker _tracker;
private boolean _reverseOrder;
/**
* Creates an instance if this class.
* @param tracker The asociated ObjectTracker instance
* @param reverseOrder True if reverse order should be applied.
*/
public ObjectMolderPriorityComparator(
final ObjectTracker tracker, final boolean reverseOrder) {
_tracker = tracker;
_reverseOrder = reverseOrder;
}
public int compare(final Object object1, final Object object2) {
Map.Entry entry1 = (Map.Entry) object1;
Map.Entry entry2 = (Map.Entry) object2;
long oper1 = ((Long) entry1.getValue()).longValue();
long oper2 = ((Long) entry2.getValue()).longValue();
ClassMolder molder1 = _tracker.getMolderForObject(entry1.getKey());
ClassMolder molder2 = _tracker.getMolderForObject(entry2.getKey());
if (molder1 == null || molder2 == null) {
if (oper1 > oper2) {
return 1;
} else if (oper1 < oper2) {
return -1;
} else {
return 0;
}
}
int pri1 = molder1.getPriority();
int pri2 = molder2.getPriority();
if (pri1 == pri2) {
if (oper1 > oper2) {
return 1;
}
if (oper1 < oper2) {
return -1;
}
return 0;
}
if (_reverseOrder) {
return (pri1 < pri2) ? 1 : -1;
}
return (pri1 < pri2) ? -1 : 1;
}
}
//--------------------------------------------------------------------------
}