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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;

/**
 * 

Purpose: 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); } // bug 6342382: object's lock value is null, it is NOT newer than any newWriteLockFieldValue. if(writeLockFieldValue == null) { return false; } // 2.5.1.6 if the write lock value is null, then what ever we have is treated as newer. if (newWriteLockFieldValue == null) { return true; } if (!(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); } // bug 6342382: object's lock value is null, it is NOT newer than any newWriteLockFieldValue. if(writeLockFieldValue == null) { return false; } // 2.5.1.6 if the write lock value is null, then what ever we have is treated as newer. if (newWriteLockFieldValue == null) { return true; } if (!(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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