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package oracle.toplink.essentials.descriptors;
import oracle.toplink.essentials.internal.sessions.*;
import java.util.*;
import java.sql.Timestamp;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.internal.helper.*;
import oracle.toplink.essentials.queryframework.*;
import oracle.toplink.essentials.exceptions.*;
import oracle.toplink.essentials.internal.sessions.AbstractRecord;
import oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl;
import oracle.toplink.essentials.internal.sessions.AbstractSession;
/**
* <p><b>Purpose</b>: Used to allow a single version timestamp to be used for optimistic locking.
*
* @since TOPLink/Java 2.0
*/
public class TimestampLockingPolicy extends VersionLockingPolicy {
protected int retrieveTimeFrom;
public final static int SERVER_TIME = 1;
public final static int LOCAL_TIME = 2;
/**
* PUBLIC:
* Create a new TimestampLockingPolicy.
* Defaults to using the time retrieved from the server.
*/
public TimestampLockingPolicy() {
super();
this.useServerTime();
}
/**
* PUBLIC:
* Create a new TimestampLockingPolicy.
* Defaults to using the time retrieved from the server.
* @param fieldName the field where the write lock value will be stored.
*/
public TimestampLockingPolicy(String fieldName) {
super(fieldName);
this.useServerTime();
}
/**
* INTERNAL:
* Create a new TimestampLockingPolicy.
* Defaults to using the time retrieved from the server.
* @param field the field where the write lock value will be stored.
*/
public TimestampLockingPolicy(DatabaseField field) {
super(field);
this.useServerTime();
}
/**
* INTERNAL:
* This method compares two writeLockValues.
* The writeLockValues should be non-null and of type java.sql.Timestamp.
* Returns:
* -1 if value1 is less (older) than value2;
* 0 if value1 equals value2;
* 1 if value1 is greater (newer) than value2.
* Throws:
* NullPointerException if the passed value is null;
* ClassCastException if the passed value is of a wrong type.
*/
public int compareWriteLockValues(Object value1, Object value2) {
java.sql.Timestamp timestampValue1 = (java.sql.Timestamp)value1;
java.sql.Timestamp timestampValue2 = (java.sql.Timestamp)value2;
return timestampValue1.compareTo(timestampValue2);
}
/**
* INTERNAL:
* Return the default timestamp locking filed java type, default is Timestamp.
*/
protected Class getDefaultLockingFieldType() {
return ClassConstants.TIMESTAMP;
}
/**
* INTERNAL:
* This is the base value that is older than all other values, it is used in the place of
* null in some situations.
*/
public Object getBaseValue(){
return new Timestamp(0);
}
/**
* INTERNAL:
* returns the initial locking value
*/
protected Object getInitialWriteValue(AbstractSession session) {
if (usesLocalTime()) {
return new Timestamp(System.currentTimeMillis());
}
if (usesServerTime()) {
AbstractSession readSession = session.getSessionForClass(getDescriptor().getJavaClass());
while (readSession.isUnitOfWork()) {
readSession = ((UnitOfWorkImpl)readSession).getParent().getSessionForClass(getDescriptor().getJavaClass());
}
return readSession.getDatasourceLogin().getDatasourcePlatform().getTimestampFromServer(session, readSession.getName());
}
return null;
}
/**
* INTERNAL:
* Returns the new Timestamp value.
*/
public Object getNewLockValue(ModifyQuery query) {
return getInitialWriteValue(query.getSession());
}
/**
* INTERNAL:
* Return the value that should be stored in the identity map. If the value
* is stored in the object, then return a null.
*/
public Object getValueToPutInCache(AbstractRecord row, AbstractSession session) {
if (isStoredInCache()) {
return session.getDatasourcePlatform().convertObject(row.get(getWriteLockField()), ClassConstants.TIMESTAMP);
} else {
return null;
}
}
/**
* INTERNAL:
* Return the number of versions different between these objects.
*/
public int getVersionDifference(Object currentValue, Object domainObject, Vector primaryKeys, AbstractSession session) {
java.sql.Timestamp writeLockFieldValue;
java.sql.Timestamp newWriteLockFieldValue = (java.sql.Timestamp)currentValue;
if (newWriteLockFieldValue == null) {
return 0;//merge it as either the object is new or being forced merged.
}
if (isStoredInCache()) {
writeLockFieldValue = (java.sql.Timestamp)session.getIdentityMapAccessor().getWriteLockValue(primaryKeys, domainObject.getClass());
} else {
writeLockFieldValue = (java.sql.Timestamp)lockValueFromObject(domainObject);
}
if ((writeLockFieldValue != null) && !(newWriteLockFieldValue.after(writeLockFieldValue))) {
return 0;
}
//if the new value is newer then perform the update. Eventually this will be changed to
//record the old version and compare that for equality
return 2;
}
/**
* INTERNAL:
* This method will return the optimistic lock value for the object
*/
public Object getWriteLockValue(Object domainObject, java.util.Vector primaryKey, AbstractSession session) {
java.sql.Timestamp writeLockFieldValue = null;
if (isStoredInCache()) {
writeLockFieldValue = (java.sql.Timestamp)session.getIdentityMapAccessor().getWriteLockValue(primaryKey, domainObject.getClass());
} else {
//CR#2281 notStoredInCache prevent ClassCastException
Object lockValue = lockValueFromObject(domainObject);
if (lockValue != null) {
if (lockValue instanceof java.sql.Timestamp) {
writeLockFieldValue = (java.sql.Timestamp)lockValueFromObject(domainObject);
} else {
throw OptimisticLockException.needToMapJavaSqlTimestampWhenStoredInObject();
}
}
}
return writeLockFieldValue;
}
/**
* INTERNAL:
* Retrun an expression that updates the write lock
*/
public Expression getWriteLockUpdateExpression(ExpressionBuilder builder) {
return builder.value(getInitialWriteValue(builder.getSession()));
}
/**
* INTERNAL:
* Timestamp versioning should not be able to do this. Override the superclass behaviour.
*/
protected Number incrementWriteLockValue(Number numberValue) {
return null;
}
/**
* INTERNAL:
* Update the parent write lock value if the objectChangeSet's is greater.
*/
public boolean isChildWriteLockValueGreater(AbstractSession session, java.util.Vector primaryKey, Class original, ObjectChangeSet changeSet) {
if (isStoredInCache()) {
// If this uow changed the object the version must be updated,
// we can check this by ensuring our value is greater than our parent's.
java.sql.Timestamp writeLockValue = (java.sql.Timestamp)changeSet.getWriteLockValue();
java.sql.Timestamp parentValue = (java.sql.Timestamp)session.getIdentityMapAccessor().getWriteLockValue(primaryKey, original);
if (writeLockValue != null) {// This occurs if the object was deleted
if ((parentValue == null) || parentValue.before(writeLockValue)) {// Check parent value is less than child
return true;
}
}
}
return false;
}
/**
* INTERNAL:
* Update the parent write lock value if the unit of works has been incremented.
*/
public boolean isChildWriteLockValueGreater(UnitOfWorkImpl uow, java.util.Vector primaryKey, Class original) {
if (isStoredInCache()) {
// If this uow changed the object the version must be updated,
// we can check this by ensuring our value is greater than our parent's.
java.sql.Timestamp writeLockValue = (java.sql.Timestamp)uow.getIdentityMapAccessor().getWriteLockValue(primaryKey, original);
java.sql.Timestamp parentValue = (java.sql.Timestamp)uow.getParent().getIdentityMapAccessor().getWriteLockValue(primaryKey, original);
if (writeLockValue != null) {// This occurs if the object was deleted
if ((parentValue == null) || parentValue.before(writeLockValue)) {// Check parent value is less than child
return true;
}
}
}
return false;
}
/**
* INTERNAL:
* Compares the value with the value from the object (or cache).
* Will return true if the object is newer.
*/
public boolean isNewerVersion(Object currentValue, Object domainObject, java.util.Vector primaryKey, AbstractSession session) {
java.sql.Timestamp writeLockFieldValue;
java.sql.Timestamp newWriteLockFieldValue = (java.sql.Timestamp)currentValue;
if (isStoredInCache()) {
writeLockFieldValue = (java.sql.Timestamp)session.getIdentityMapAccessor().getWriteLockValue(primaryKey, domainObject.getClass());
} else {
writeLockFieldValue = (java.sql.Timestamp)lockValueFromObject(domainObject);
}
if ((writeLockFieldValue != null) && !(newWriteLockFieldValue.after(writeLockFieldValue))) {
return false;
}
return true;
}
/**
* INTERNAL:
* Compares the value from the row and from the object (or cache).
* Will return true if the object is newer than the row.
*/
public boolean isNewerVersion(AbstractRecord databaseRow, Object domainObject, java.util.Vector primaryKey, AbstractSession session) {
java.sql.Timestamp writeLockFieldValue;
java.sql.Timestamp newWriteLockFieldValue = (java.sql.Timestamp)session.getDatasourcePlatform().convertObject(databaseRow.get(getWriteLockField()), ClassConstants.TIMESTAMP);
if (isStoredInCache()) {
writeLockFieldValue = (java.sql.Timestamp)session.getIdentityMapAccessor().getWriteLockValue(primaryKey, domainObject.getClass());
} else {
writeLockFieldValue = (java.sql.Timestamp)lockValueFromObject(domainObject);
}
if ((writeLockFieldValue != null) && !(newWriteLockFieldValue.after(writeLockFieldValue))) {
return false;
}
return true;
}
/**
* PUBLIC:
* Set if policy uses server time.
*/
public void setUsesServerTime(boolean usesServerTime) {
if (usesServerTime) {
useServerTime();
} else {
useLocalTime();
}
}
/**
* PUBLIC:
* set this policy to get the time from the local machine.
*/
public void useLocalTime() {
retrieveTimeFrom = LOCAL_TIME;
}
/**
* PUBLIC:
* set this policy to get the time from the server.
*/
public void useServerTime() {
retrieveTimeFrom = SERVER_TIME;
}
/**
* PUBLIC:
* Return true if policy uses local time.
*/
public boolean usesLocalTime() {
return (retrieveTimeFrom == LOCAL_TIME);
}
/**
* PUBLIC:
* Return true if policy uses server time.
*/
public boolean usesServerTime() {
return (retrieveTimeFrom == SERVER_TIME);
}
}
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