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package oracle.toplink.essentials.queryframework;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.util.*;
import oracle.toplink.essentials.internal.expressions.*;
import oracle.toplink.essentials.internal.helper.Helper;
import oracle.toplink.essentials.mappings.DatabaseMapping;
import oracle.toplink.essentials.internal.security.PrivilegedAccessHelper;
import oracle.toplink.essentials.internal.security.PrivilegedClassForName;
import oracle.toplink.essentials.internal.sessions.MergeManager;
import oracle.toplink.essentials.exceptions.ValidationException;
import oracle.toplink.essentials.internal.sessions.AbstractRecord;
import oracle.toplink.essentials.internal.sessions.UnitOfWorkImpl;
import oracle.toplink.essentials.descriptors.ClassDescriptor;
import oracle.toplink.essentials.internal.queryframework.JoinedAttributeManager;
/**
* <p><b>Purpose</b>:
* Abstract class for all read queries that build objects and potentially manipulate
* the TopLink cache.
*
* <p><b>Description</b>:
* Contains common behavior for all read queries building objects.
*
* @author Gordon Yorke
* @since TopLink Essentials
*/
public abstract class ObjectBuildingQuery extends ReadQuery {
/** The class of the target objects to be read from the database. */
protected Class referenceClass;
protected String referenceClassName;
/** Allows for the resulting objects to be refresh with the data from the database. */
protected boolean shouldRefreshIdentityMapResult;
protected boolean shouldRefreshRemoteIdentityMapResult;
/** INTERNAL: for bug 2612601 allow ability not to register results in UOW. */
protected boolean shouldRegisterResultsInUnitOfWork = true;
/** CMP only. Allow users to configure whether finder should be executed in a uow or not. */
protected boolean shouldProcessResultsInUnitOfWork = true;
/** Used for pessimistic locking. */
protected ForUpdateClause lockingClause;
public static final short NO_LOCK = 0;
public static final short LOCK = 1;
public static final short LOCK_NOWAIT = 2;
// allow pessimistic locking policy to be used
public static final short DEFAULT_LOCK_MODE = -1;
protected boolean isPrePrepared;
/**
* Used to set the read time on objects that use this query.
* Should be set to the time the query returned from the database.
*/
protected long executionTime = 0;
/**
* Added for Exclusive Connection (VPD) support see accessor for information
*/
protected boolean shouldUseExclusiveConnection = false;
/**
* INTERNAL: This is the key for accessing unregistered and locked result in the query's properties.
* The uow and QueryBaseValueHolder use this property to record amd to retreive the result respectively.
*/
public static final String LOCK_RESULT_PROPERTY = "LOCK_RESULT";
/** PERF: Store if the query originally used the default lock mode. */
protected boolean wasDefaultLockMode = false;
/**
* INTERNAL:
* Initialize the state of the query
*/
public ObjectBuildingQuery() {
this.shouldRefreshIdentityMapResult = false;
}
/**
* INTERNAL:
* Convert all the class-name-based settings in this query to actual class-based
* settings. This method is used when converting a project that has been built
* with class names to a project with classes.
* @param classLoader
*/
public void convertClassNamesToClasses(ClassLoader classLoader){
super.convertClassNamesToClasses(classLoader);
Class referenceClass = null;
try{
if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){
try {
referenceClass = (Class)AccessController.doPrivileged(new PrivilegedClassForName(getReferenceClassName(), true, classLoader));
} catch (PrivilegedActionException exception) {
throw ValidationException.classNotFoundWhileConvertingClassNames(getReferenceClassName(), exception.getException());
}
} else {
referenceClass = oracle.toplink.essentials.internal.security.PrivilegedAccessHelper.getClassForName(getReferenceClassName(), true, classLoader);
}
} catch (ClassNotFoundException exc){
throw ValidationException.classNotFoundWhileConvertingClassNames(getReferenceClassName(), exc);
}
setReferenceClass(referenceClass);
};
/**
* INTERNAL:
* Return if this query originally used the default lock mode.
*/
protected boolean wasDefaultLockMode() {
return wasDefaultLockMode;
}
/**
* INTERNAL:
* Set if this query originally used the default lock mode.
*/
protected void setWasDefaultLockMode(boolean wasDefaultLockMode) {
this.wasDefaultLockMode = wasDefaultLockMode;
}
/**
* PUBLIC:
* When unset means perform read normally and dont do refresh.
*/
public void dontRefreshIdentityMapResult() {
setShouldRefreshIdentityMapResult(false);
}
/**
* PUBLIC:
* When unset means perform read normally and dont do refresh.
*/
public void dontRefreshRemoteIdentityMapResult() {
setShouldRefreshRemoteIdentityMapResult(false);
}
/**
* Return the fetch group set in the query.
* If a fetch group is not explicitly set in the query, default fetch group optionally defined in the decsiptor
* would be used, unless the user explicitly calls query.setShouldUseDefaultFetchGroup(false).
*/
public FetchGroup getFetchGroup() {
return null;
}
/**
* PUBLIC:
* Return the current locking mode.
*/
public short getLockMode() {
if (lockingClause == null) {
return DEFAULT_LOCK_MODE;
} else {
return lockingClause.getLockMode();
}
}
/**
* INTERNAL:
* Return all of the rows fetched by the query, used for 1-m joining.
*/
public List getDataResults() {
return null;
}
/**
* INTERNAL:
* Return the time this query actually went to the database
*/
public long getExecutionTime() {
return executionTime;
}
/**
* PUBLIC:
* Return the reference class of the query.
*/
public Class getReferenceClass() {
return referenceClass;
}
/**
* INTERNAL:
* Return the reference class of the query.
*/
public String getReferenceClassName() {
if ((referenceClassName == null) && (referenceClass != null)) {
referenceClassName = referenceClass.getName();
}
return referenceClassName;
}
/**
* INTERNAL:
* Return if partial attributes.
*/
public boolean hasPartialAttributeExpressions() {
return false;
}
/**
* PUBLIC:
* Answers if the query lock mode is known to be LOCK or LOCK_NOWAIT.
*
* In the case of DEFAULT_LOCK_MODE and the query reference class being a CMP entity bean,
* at execution time LOCK, LOCK_NOWAIT, or NO_LOCK will be decided.
* <p>
* If a single joined attribute was configured for pessimistic locking then
* this will return true (after first execution) as the SQL contained a
* FOR UPDATE OF clause.
*/
public boolean isLockQuery() {
return getLockMode() > NO_LOCK;
}
/**
* PUBLIC:
* Return if this is an object building query.
*/
public boolean isObjectBuildingQuery() {
return true;
}
/**
* INTERNAL:
* Answers if we are executing through a UnitOfWork and registering results.
* This is only ever false if using the conforming without registering
* feature.
*/
protected boolean isRegisteringResults() {
return ((shouldRegisterResultsInUnitOfWork() && getDescriptor().shouldRegisterResultsInUnitOfWork()) || isLockQuery());
}
/**
* PUBLIC:
* Refresh the attributes of the object(s) resulting from the query.
* If cascading is used the private parts of the objects will also be refreshed.
*/
public void refreshIdentityMapResult() {
setShouldRefreshIdentityMapResult(true);
}
/**
* PUBLIC:
* Refresh the attributes of the object(s) resulting from the query.
* If cascading is used the private parts of the objects will also be refreshed.
*/
public void refreshRemoteIdentityMapResult() {
setShouldRefreshRemoteIdentityMapResult(true);
}
/**
* INTERNAL:
* Constructs the final (registered) object for every individual object
* queried via a UnitOfWork.
* <p>
* Called for every object in a read all, the object in a read object, and
* every time the next or previous row is retrieved from a cursor.
* <p>
* The (conform) without registering feature is implemented here, and may
* return an original non UnitOfWork registered result.
* <p>
* Pessimistically locked objects are tracked here.
*
* @param result may be an object (in the identity map of the parent session),
* which becomes the original, or a raw database row if in transaction.
* @param buildDirectlyFromRows true if must construct
* a registered result from raw database rows.
*
* @return a refreshed UnitOfWork queried object, unwrapped.
*/
public Object registerIndividualResult(Object result, UnitOfWorkImpl unitOfWork, boolean buildDirectlyFromRows, JoinedAttributeManager joinManager) {
Object clone = null;
if (buildDirectlyFromRows) {
// This method will either call back later with buildDirectlyFromRows == false,
// or special code which builds/refreshes clones directly from the
// row will be invoked.
return buildObject((AbstractRecord)result);
}
// For bug 2612601 Conforming without registering in Unit Of Work.
else if (!isRegisteringResults()) {
clone = unitOfWork.getIdentityMapAccessorInstance().getIdentityMapManager().getFromIdentityMap(result);
// If object not registered do not register it here! Simply return
// the original to the user.
// Avoid setting clone = original, in case revert(clone) is called.
if (clone == null) {
clone = result;
}
} else {
// bug # 3183379 either the object comes from the shared cache and is existing, or
//it is from a parent unit of work and this unit of work does not need to know if it is new
//or not. It will query the parent unit of work to determine newness.
clone = unitOfWork.registerExistingObject(result, joinManager);
}
// Check for refreshing, require to revert in the unit of work to accomplish a refresh.
if (shouldRefreshIdentityMapResult()) {
// Revert only works in the object is in the parent cache, if it is not merge must be used.
if (unitOfWork.getParent().getIdentityMapAccessor().containsObjectInIdentityMap(clone)) {
if (shouldCascadeAllParts()) {
unitOfWork.deepRevertObject(clone);
} else if (shouldCascadePrivateParts()) {
unitOfWork.revertObject(clone);
} else if (shouldCascadeByMapping()) {
unitOfWork.revertObject(clone, MergeManager.CASCADE_BY_MAPPING);
} else if (!shouldCascadeParts()) {
unitOfWork.shallowRevertObject(clone);
}
} else {
if (shouldCascadeAllParts()) {
unitOfWork.deepMergeClone(result);
} else if (shouldCascadePrivateParts()) {
unitOfWork.mergeClone(result);
} else if (shouldCascadeByMapping()) {
unitOfWork.mergeClone(result, MergeManager.CASCADE_BY_MAPPING);
} else if (!shouldCascadeParts()) {
unitOfWork.shallowMergeClone(result);
}
}
}
// record clone if referenced class has pessimistic locking policy
recordCloneForPessimisticLocking(clone, unitOfWork);
return clone;
}
/**
* INTERNAL:
* Set the the time this query went to the database.
*/
public void setExecutionTime(long executionTime) {
this.executionTime = executionTime;
}
/**
* PUBLIC:
* Sets whether this is a pessimistically locking query.
* <ul>
* <li>ObjectBuildingQuery.LOCK: SELECT .... FOR UPDATE issued.
* <li>ObjectBuildingQuery.LOCK_NOWAIT: SELECT .... FOR UPDATE NO WAIT issued.
* <li>ObjectBuildingQuery.NO_LOCK: no pessimistic locking.
* <li>ObjectBuildingQuery.DEFAULT_LOCK_MODE (default) and you have a CMP descriptor:
* fine grained locking will occur.
* </ul>
* <p>Fine Grained Locking: On execution the reference class
* and those of all joined attributes will be checked. If any of these have a
* PessimisticLockingPolicy set on their descriptor, they will be locked in a
* SELECT ... FOR UPDATE OF ... {NO WAIT}. Issues fewer locks
* and avoids setting the lock mode on each query.
* <p>Example:<code>readAllQuery.setSelectionCriteria(employee.get("address").equal("Ottawa"));</code>
* <ul><li>LOCK: all employees in Ottawa and all referenced Ottawa addresses will be locked.
* <li>DEFAULT_LOCK_MODE: if address is a joined attribute, and only address has a pessimistic
* locking policy, only referenced Ottawa addresses will be locked.
* </ul>
* @see oracle.toplink.essentials.descriptors.PessimisticLockingPolicy
*/
public void setLockMode(short lockMode) {
lockingClause = ForUpdateClause.newInstance(lockMode);
}
/**
* REQUIRED:
* Set the reference class for the query.
*/
public void setReferenceClass(Class aClass) {
referenceClass = aClass;
setIsPrepared(false);
}
/**
* INTERNAL:
* Set the reference class for the query.
*/
public void setReferenceClassName(String aClass) {
referenceClassName = aClass;
setIsPrepared(false);
}
/**
* PUBLIC:
* Set if the attributes of the object(s) resulting from the query should be refreshed.
* If cascading is used the private parts of the objects will also be refreshed.
*/
public void setShouldRefreshIdentityMapResult(boolean shouldRefreshIdentityMapResult) {
this.shouldRefreshIdentityMapResult = shouldRefreshIdentityMapResult;
if (shouldRefreshIdentityMapResult) {
setShouldRefreshRemoteIdentityMapResult(true);
}
}
/**
* PUBLIC:
* Set if the attributes of the object(s) resulting from the query should be refreshed.
* If cascading is used the private parts of the objects will also be refreshed.
*/
public void setShouldRefreshRemoteIdentityMapResult(boolean shouldRefreshIdentityMapResult) {
this.shouldRefreshRemoteIdentityMapResult = shouldRefreshIdentityMapResult;
}
/**
* INTERNAL:
* Set to false to have queries conform to a UnitOfWork without registering
* any additional objects not already in that UnitOfWork.
* @see #shouldRegisterResultsInUnitOfWork
* @bug 2612601
*/
public void setShouldRegisterResultsInUnitOfWork(boolean shouldRegisterResultsInUnitOfWork) {
this.shouldRegisterResultsInUnitOfWork = shouldRegisterResultsInUnitOfWork;
}
/**
* INTERNAL:
* Allows one to do conforming in a UnitOfWork without registering.
* Queries executed on a UnitOfWork will only return working copies for objects
* that have already been registered.
* <p>Extreme care should be taken in using this feature, for a user will
* get back a mix of registered and original (unregistered) objects.
* <p>Best used with a WrapperPolicy where invoking on an object will trigger
* its registration (CMP). Without a WrapperPolicy {@link oracle.toplink.essentials.sessions.UnitOfWork#registerExistingObject registerExistingObject}
* should be called on any object that you intend to change.
* @return true by default.
* @see #setShouldRegisterResultsInUnitOfWork
* @see oracle.toplink.essentials.publicinterface.Descriptor#shouldRegisterResulstInUnitOfWork
* @bug 2612601
*/
public boolean shouldRegisterResultsInUnitOfWork() {
return shouldRegisterResultsInUnitOfWork;
}
/**
* INTERNAL:
* Return if this is a full object query, not partial nor fetch group.
*/
public boolean shouldReadAllMappings() {
return true;
}
/**
* INTERNAL:
* Check if the mapping is part of the partial attributes.
*/
public boolean shouldReadMapping(DatabaseMapping mapping) {
return true;
}
/**
* PUBLIC:
* Set to a boolean. When set means refresh the instance
* variables of referenceObject from the database.
*/
public boolean shouldRefreshIdentityMapResult() {
return shouldRefreshIdentityMapResult;
}
/**
* PUBLIC:
* Set to a boolean. When set means refresh the instance
* variables of referenceObject from the database.
*/
public boolean shouldRefreshRemoteIdentityMapResult() {
return shouldRefreshRemoteIdentityMapResult;
}
public String toString() {
if (getReferenceClass() == null) {
return super.toString();
}
return Helper.getShortClassName(getClass()) + "(" + getReferenceClass().getName() + ")";
}
/**
* ADVANCED:
* Used for CMP only. This allows users to indicate whether cmp finders executed
* at the beginning of a transaction should always be run against a UnitOfWork.
* Defaults to true.
* <p>
* If set to false, then UnitOfWork allocation will be deferred until a business
* method (including creates/removes) or finder with shouldProcessResultsInUnitOfWork == true
* is invoked. Any finder executed before such a time, will do so against the
* underlying ServerSession. Forcing finder execution to always go through a
* UnitOfWork means the results will be cloned and cached in the UnitOfWork up
* front. This is desired when the results will be accessed in the same transaction.
* <p>
* Note that finders executed with an unspecified transaction context will never
* be executed against a UnitOfWork, even if this setting is true. This case may happen
* with the NotSupported, Never, and Supports attributes.
*/
public void setShouldProcessResultsInUnitOfWork(boolean processResultsInUnitOfWork) {
this.shouldProcessResultsInUnitOfWork = processResultsInUnitOfWork;
}
/**
* ADVANCED:
* Used for CMP only. Indicates whether cmp finders executed at the beginning
* of a transaction should always be run against a UnitOfWork.
* Defaults to true.
* <p>
* If set to false, then UnitOfWork allocation will be deferred until a business
* method (including creates/removes) or finder with shouldProcessResultsInUnitOfWork == true
* is invoked. Any finder executed before such a time, will do so against the
* underlying ServerSession. Forcing finder execution to always go through a
* UnitOfWork means the results will be cloned and cached in the UnitOfWork up
* front. This is desired when the results will be accessed in the same transaction.
* <p>
* Note that finders executed with an unspecified transaction context will never
* be executed against a UnitOfWork, even if this setting is true. This case may happen
* with the NotSupported, Never, and Supports attributes.
*/
public boolean shouldProcessResultsInUnitOfWork() {
return this.shouldProcessResultsInUnitOfWork;
}
/**
* INTERNAL:
* Return if the attribute is specified for joining.
*/
public boolean isAttributeJoined(ClassDescriptor mappingDescriptor, String attributeName) {
return false;
}
/**
* INTERNAL:
* Helper method that checks if clone has been locked with uow.
*/
public boolean isClonePessimisticLocked(Object clone, UnitOfWorkImpl uow) {
return false;
}
/**
* INTERNAL:
* Helper method that records clone with uow if query is pessimistic locking.
*/
public void recordCloneForPessimisticLocking(Object clone, UnitOfWorkImpl uow) {
if ((isLockQuery()) && lockingClause.isReferenceClassLocked()) {
uow.addPessimisticLockedClone(clone);
}
}
/**
* INTERNAL: Helper method to determine the default mode. If true and quey has a pessimistic locking policy,
* locking will be configured according to the pessimistic locking policy.
*/
public boolean isDefaultLock() {
return (lockingClause == null);
}
}
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