Skip navigation links

oracle.toplink.queryframework
Class ObjectLevelReadQuery

java.lang.Object
oracle.toplink.queryframework.DatabaseQuery
oracle.toplink.queryframework.ReadQuery
oracle.toplink.queryframework.ObjectLevelReadQuery

All Implemented Interfaces:

java.lang.Cloneable, java.io.Serializable

Direct Known Subclasses:

ReadAllQuery, ReadObjectQuery

public abstract class ObjectLevelReadQuery

extends ReadQuery

Purpose: Abstract class for all read queries using objects.

Description: Contains common behavior for all read queries using objects.

Since:

TOPLink/Java 1.0

See Also:

Serialized Form

Field Summary

static int	CheckCacheByExactPrimaryKey
static int	CheckCacheByPrimaryKey
static int	CheckCacheOnly
static int	CheckCacheThenDatabase
static int	ConformResultsInUnitOfWork
static short	DEFAULT_LOCK_MODE
static int	DoNotCheckCache
static short	DONT_USE_DISTINCT
static short	LOCK
static short	LOCK_NOWAIT
static short	NO_LOCK
static short	UNCOMPUTED_DISTINCT
static short	USE_DISTINCT
static int	UseDescriptorSetting

Fields inherited from class oracle.toplink.queryframework.DatabaseQuery

CascadeAggregateDelete, CascadeAllParts, CascadeByMapping, CascadeDependentParts, CascadePrivateParts, NoCascading

Method Summary

void	acquireLocks() PUBLIC: Set the query to lock, this will also turn refreshCache on.
void	acquireLocksWithoutWaiting() PUBLIC: Set the query to lock without waiting (blocking), this will also turn refreshCache on.
void	addJoinedAttribute(Expression attributeExpression) PUBLIC: Specify the one-to-one mapped attribute to be optimized in this query.
void	addJoinedAttribute(java.lang.String attributeName) PUBLIC: Specify the one-to-one mapped attribute to be optimized in this query.
void	addPartialAttribute(Expression attributeExpression) PUBLIC: Specify that only a subset of the class' attributes be selected in this query.
void	addPartialAttribute(java.lang.String attributeName) PUBLIC: Specify that only a subset of the class' attributes be selected in this query.
void	checkCacheOnly() PUBLIC: The cache will checked completely, if the object is not found null will be returned or an error if the query is too complex.
void	conformResultsInUnitOfWork() PUBLIC: The cache will checked completely, if the object is not found the database will be queried, and the database result will be verified with what is in the cache and/or unit of work including new objects.
void	dontAcquireLocks() PUBLIC: Set the query not to lock.
void	dontCheckCache() PUBLIC: This can be used to explicitly disable the cache hit.
void	dontRefreshIdentityMapResult() PUBLIC: When unset means perform read normally and dont do refresh.
void	dontRefreshRemoteIdentityMapResult() PUBLIC: When unset means perform read normally and dont do refresh.
void	dontUseDistinct() ADVANCED: If a distinct has been set the DISTINCT clause will be printed.
java.lang.Object	executeDatabaseQuery() INTERNAL: Execute the query
AsOfClause	getAsOfClause() ADVANCED: Answers the past time this query is as of.
int	getCacheUsage() PUBLIC: Return the cache usage.
short	getDistinctState() ADVANCED: If a distinct has been set the DISTINCT clause will be printed.
java.lang.Object	getExampleObject() PUBLIC: This method returns the current example object.
ExpressionBuilder	getExpressionBuilder() REQUIRED: Get the expression builder which should be used for this query.
FetchGroup	getFetchGroup() Return the fetch group set in the query.
java.lang.String	getFetchGroupName() Return the fetch group name set in the query.
InMemoryQueryIndirectionPolicy	getInMemoryQueryIndirectionPolicy() PUBLIC: Returns the InMemoryQueryIndirectionPolicy for this query
short	getLockMode() PUBLIC: Return the current locking mode.
QueryByExamplePolicy	getQueryByExamplePolicy() PUBLIC: When using Query By Example, an instance of QueryByExamplePolicy is used to customize the query.
java.lang.Class	getReferenceClass() PUBLIC: Return the reference class of the query.
boolean	hasAsOfClause() PUBLIC: Answers if the domain objects are to be read as of a past time.
boolean	hasFetchGroup() Return if a fetch group is set in the query.
boolean	isLockQuery() PUBLIC: Answers if the query lock mode is known to be LOCK or LOCK_NOWAIT.
boolean	isLockQuery(Session session) ADVANCED: Answers if this query will issue any pessimistic locks.
boolean	isObjectLevelReadQuery() PUBLIC: Return if this is an object level read query.
void	refreshIdentityMapResult() PUBLIC: Refresh the attributes of the object(s) resulting from the query.
void	refreshRemoteIdentityMapResult() PUBLIC: Refresh the attributes of the object(s) resulting from the query.
void	resetDistinct() ADVANCED: If a distinct has been set the DISTINCT clause will be printed.
void	setAsOfClause(AsOfClause pastTime) ADVANCED: Sets the query to execute as of the past time.
void	setCacheUsage(int cacheUsage) PUBLIC: Set the cache usage.
void	setDistinctState(short distinctState) ADVANCED: If a distinct has been set the DISTINCT clause will be printed.
void	setEJBQLString(java.lang.String ejbqlString) PUBLIC: To any user of this object.
void	setExampleObject(java.lang.Object newExampleObject) PUBLIC: Set the example object of the query to be the newExampleObject.
void	setFetchGroup(FetchGroup newFetchGroup) Set a dynamic (use case) fetch group to the query.
void	setFetchGroupName(java.lang.String groupName) Set a descriptor-level pre-defined named fetch group to the query.
void	setInMemoryQueryIndirectionPolicy(InMemoryQueryIndirectionPolicy inMemoryQueryIndirectionPolicy) PUBLIC: Set the InMemoryQueryIndirectionPolicy for this query
void	setLockMode(short lockMode) PUBLIC: Sets whether this is a pessimistically locking query.
void	setQueryByExamplePolicy(QueryByExamplePolicy queryByExamplePolicy) PUBLIC: The QueryByExamplePolicy, is a useful to customize the query when Query By Example is used.
void	setReferenceClass(java.lang.Class aClass) REQUIRED: Set the reference class for the query.
void	setSelectionCriteria(Expression expression) PUBLIC: To any user of this object.
void	setShouldProcessResultsInUnitOfWork(boolean processResultsInUnitOfWork) ADVANCED: Used for CMP only.
void	setShouldRefreshIdentityMapResult(boolean shouldRefreshIdentityMapResult) PUBLIC: Set if the attributes of the object(s) resulting from the query should be refreshed.
void	setShouldRefreshRemoteIdentityMapResult(boolean shouldRefreshIdentityMapResult) PUBLIC: Set if the attributes of the object(s) resulting from the query should be refreshed.
void	setShouldUseDefaultFetchGroup(boolean shouldUseDefaultFetchGroup) Set false if the user does not want to use the default fetch group defined in the descriptor level.
void	setShouldUseExclusiveConnection(boolean shouldUseExclusiveConnection) ADVANCED: If the user has isolated data and specified that the client session should use an exclusive connection then by setting this condition to true TopLink will ensure that the query is executed through the exclusive connection.
boolean	shouldCheckCacheOnly() PUBLIC: Return if cache should be checked.
boolean	shouldCheckDescriptorForCacheUsage() PUBLIC: Return whether the descriptor's disableCacheHits setting should be checked prior to querying the cache.
boolean	shouldConformResultsInUnitOfWork() PUBLIC: Should the results will be checked against the changes within the unit of work and object no longer matching or deleted will be remove, matching new objects will also be added..
boolean	shouldProcessResultsInUnitOfWork() ADVANCED: Used for CMP only.
boolean	shouldRefreshIdentityMapResult() PUBLIC: Set to a boolean.
boolean	shouldRefreshRemoteIdentityMapResult() PUBLIC: Set to a boolean.
boolean	shouldUseDefaultFetchGroup() Return false if the query does not use the default fetch group defined in the descriptor level.
boolean	shouldUseExclusiveConnection() ADVANCED: If the user has isolated data and specified that the client session should use an exclusive connection then by setting this condition to true TopLink will ensure that the query is executed through the exclusive connection.
java.lang.String	toString()
void	useDistinct() ADVANCED: If a distinct has been set the DISTINCT clause will be printed.

Methods inherited from class oracle.toplink.queryframework.ReadQuery

cacheQueryResults, clearQueryResults, clearQueryResults, doNotCacheQueryResults, getFetchSize, getFirstResult, getMaxRows, getQueryResultsCachePolicy, isReadQuery, setFetchSize, setFirstResult, setMaxRows, setQueryResultsCachePolicy, setShouldCacheQueryResults, shouldCacheQueryResults

Methods inherited from class oracle.toplink.queryframework.DatabaseQuery

addArgument, addArgument, addArgument, addArgumentValue, addArgumentValues, addCall, addStatement, bindAllParameters, cacheStatement, cascadeAllParts, cascadeByMapping, cascadePrivateParts, dontBindAllParameters, dontCacheStatement, dontCascadeParts, dontMaintainCache, getCall, getCalls, getDatasourceCall, getDatasourceCalls, getEJBQLString, getHintString, getName, getQueryTimeout, getRedirector, getSelectionCriteria, getSessionName, getSQLStatement, getSQLString, getSQLStrings, getTranslatedSQLString, getTranslatedSQLStrings, hasSessionName, ignoreBindAllParameters, ignoreCacheStatement, isCallQuery, isDataModifyQuery, isDataReadQuery, isDeleteObjectQuery, isExpressionQuery, isInsertObjectQuery, isModifyQuery, isObjectLevelModifyQuery, isReadAllQuery, isReadObjectQuery, isReportQuery, isSQLCallQuery, isUpdateAllQuery, isUpdateObjectQuery, isWriteObjectQuery, maintainCache, prepareCall, setCall, setDatasourceCall, setHintString, setName, setQueryTimeout, setRedirector, setSessionName, setShouldBindAllParameters, setShouldCacheStatement, setShouldMaintainCache, setShouldPrepare, setShouldUseWrapperPolicy, setSQLStatement, setSQLString, shouldBindAllParameters, shouldCacheStatement, shouldCascadeAllParts, shouldCascadeByMapping, shouldCascadeParts, shouldCascadePrivateParts, shouldIgnoreBindAllParameters, shouldIgnoreCacheStatement, shouldMaintainCache, shouldPrepare, shouldUseWrapperPolicy

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

UseDescriptorSetting

public static final int UseDescriptorSetting

See Also:

Constant Field Values

DoNotCheckCache

public static final int DoNotCheckCache

See Also:

Constant Field Values

CheckCacheByExactPrimaryKey

public static final int CheckCacheByExactPrimaryKey

See Also:

Constant Field Values

CheckCacheByPrimaryKey

public static final int CheckCacheByPrimaryKey

See Also:

Constant Field Values

CheckCacheThenDatabase

public static final int CheckCacheThenDatabase

See Also:

Constant Field Values

CheckCacheOnly

public static final int CheckCacheOnly

See Also:

Constant Field Values

ConformResultsInUnitOfWork

public static final int ConformResultsInUnitOfWork

See Also:

Constant Field Values

NO_LOCK

public static final short NO_LOCK

See Also:

Constant Field Values

LOCK

public static final short LOCK

See Also:

Constant Field Values

LOCK_NOWAIT

public static final short LOCK_NOWAIT

See Also:

Constant Field Values

DEFAULT_LOCK_MODE

public static final short DEFAULT_LOCK_MODE

See Also:

Constant Field Values

UNCOMPUTED_DISTINCT

public static final short UNCOMPUTED_DISTINCT

See Also:

Constant Field Values

USE_DISTINCT

public static final short USE_DISTINCT

See Also:

Constant Field Values

DONT_USE_DISTINCT

public static final short DONT_USE_DISTINCT

See Also:

Constant Field Values

Method Detail

acquireLocks

public void acquireLocks()

PUBLIC: Set the query to lock, this will also turn refreshCache on.

acquireLocksWithoutWaiting

public void acquireLocksWithoutWaiting()

PUBLIC: Set the query to lock without waiting (blocking), this will also turn refreshCache on.

addJoinedAttribute

public void addJoinedAttribute(java.lang.String attributeName)

PUBLIC: Specify the one-to-one mapped attribute to be optimized in this query. The query will join the object(s) being read with the one-to-one attribute, this allows all of the data required for the object(s) to be read in a single query instead of (n) queries. This should be used when the application knows that it requires the part for all of the objects being read. This can be used only for one-to-one mappings where the target is not the same class as the source, either directly or through inheritance. Also two joins cannot be done to the same class.

Note: This cannot be used for objects where it is possible not to have a part, as these objects will be ommited from the result set, unless an outer join is used through passing and expression using "getAllowingNull".

Example: query.addJoinedAttribute("address")

See Also:

addJoinedAttribute(Expression), ReadAllQuery.addBatchReadAttribute(Expression)

addJoinedAttribute

public void addJoinedAttribute(Expression attributeExpression)

PUBLIC: Specify the one-to-one mapped attribute to be optimized in this query. The query will join the object(s) being read with the one-to-one attribute, this allows all of the data required for the object(s) to be read in a single query instead of (n) queries. This should be used when the application knows that it requires the part for all of the objects being read. This can be used only for one-to-one mappings where the target is not the same class as the source, either directly or through inheritance. Also two joins cannot be done to the same class.

Note: This cannot be used for objects where it is possible not to have a part, as these objects will be ommited from the result set, unless an outer join is used through passing and expression using "getAllowingNull".

Example: query.addJoinedAttribute(query.getExpressionBuilder().get("teamLeader").get("address"))

See Also:

ReadAllQuery.addBatchReadAttribute(String)

addPartialAttribute

public void addPartialAttribute(java.lang.String attributeName)

PUBLIC: Specify that only a subset of the class' attributes be selected in this query.

This allows for the query to be optimized through selecting less data.

Partial objects will be returned from the query, where the unspecified attributes will be left null. The primary key will always be selected to allow re-querying of the whole object.

Note: Because the object is not fully initialized it cannot be cached, and cannot be edited.

Note: You cannot have 2 partial attributes of the same type. You also cannot add a partial attribute which is of the same type as the class being queried.

Example: query.addPartialAttribute("firstName")

See Also:

addPartialAttribute(Expression)

setAsOfClause

public void setAsOfClause(AsOfClause pastTime)

ADVANCED: Sets the query to execute as of the past time. Both the query execution and result will conform to the database as it existed in the past.

Equivalent to query.getSelectionCriteria().asOf(pastTime) called immediately before query execution.

An as of clause at the query level will override any clauses set at the expression level. Useful in cases where the selection criteria is not known in advance, such as for query by example or primary key (selection object), or where you do not need to cache the result (report query).

Ideally an as of clause at the session level is superior as query results can then be cached. You must set setShouldMaintainCache(false)

To query all joined/batched attributes as of the same time set this.cascadeAllParts().

Throws:

QueryException - (at execution time) unless setShouldMaintainCache(false) is set. If some more recent data were in the cache, this would be returned instead, and both the cache and query result would become inconsistent.

Since:

OracleAS TopLink 10g (10.0.3)

See Also:

hasAsOfClause(), Session.acquireHistoricalSession(oracle.toplink.history.AsOfClause), Expression.asOf(oracle.toplink.history.AsOfClause)

addPartialAttribute

public void addPartialAttribute(Expression attributeExpression)

PUBLIC: Specify that only a subset of the class' attributes be selected in this query.

This allows for the query to be optimized through selecting less data.

Partial objects will be returned from the query, where the unspecified attributes will be left null. The primary key will always be selected to allow re-querying of the whole object.

Note: Because the object is not fully initialized it cannot be cached, and cannot be edited.

Note: You cannot have 2 partial attributes of the same type. You also cannot add a partial attribute which is of the same type as the class being queried.

Example: query.addPartialAttribute(query.getExpressionBuilder().get("address").get("city"))

checkCacheOnly

public void checkCacheOnly()

PUBLIC: The cache will checked completely, if the object is not found null will be returned or an error if the query is too complex. Queries can be configured to use the cache at several levels. Other caching option are available.

See Also:

setCacheUsage(int)

conformResultsInUnitOfWork

public void conformResultsInUnitOfWork()

PUBLIC: The cache will checked completely, if the object is not found the database will be queried, and the database result will be verified with what is in the cache and/or unit of work including new objects. This can lead to poor performance so it is recomended that only the database be queried in most cases. Queries can be configured to use the cache at several levels. Other caching option are available.

See Also:

setCacheUsage(int)

dontAcquireLocks

public void dontAcquireLocks()

PUBLIC: Set the query not to lock.

dontCheckCache

public void dontCheckCache()

PUBLIC: This can be used to explicitly disable the cache hit. The cache hit may not be desired in some cases, such as stored procedures that accept the primary key but do not query on it.

dontRefreshIdentityMapResult

public void dontRefreshIdentityMapResult()

PUBLIC: When unset means perform read normally and dont do refresh.

dontRefreshRemoteIdentityMapResult

public void dontRefreshRemoteIdentityMapResult()

PUBLIC: When unset means perform read normally and dont do refresh.

dontUseDistinct

public void dontUseDistinct()

ADVANCED: If a distinct has been set the DISTINCT clause will be printed. This is used internally by TopLink for batch reading but may also be used directly for advanced queries or report queries.

executeDatabaseQuery

public java.lang.Object executeDatabaseQuery()
                                      throws DatabaseException

Description copied from class: DatabaseQuery

INTERNAL: Execute the query

Specified by:

executeDatabaseQuery in class DatabaseQuery

Returns:

- the result of executing the query.

Throws:

DatabaseException - - an error has occurred on the database.

getAsOfClause

public AsOfClause getAsOfClause()

ADVANCED: Answers the past time this query is as of.

Returns:

An immutable object representation of the past time. null if no clause set, AsOfClause.NO_CLAUSE if clause explicitly set to null.

See Also:

AsOfClause, setAsOfClause(oracle.toplink.history.AsOfClause), hasAsOfClause()

getCacheUsage

public int getCacheUsage()

PUBLIC: Return the cache usage. By default only primary key read object queries will first check the cache before accessing the database. Any query can be configure to query against the cache completely, by key or ignore the cache check.

Valid values are:

• DoNotCheckCache
• CheckCacheByExactPrimaryKey
• CheckCacheByPrimaryKey
• CheckCacheThenDatabase
• CheckCacheOnly
• ConformResultsInUnitOfWork
• UseDescriptorSetting Note: UseDescriptorSetting functions like CheckCacheByPrimaryKey, except checks the appropriate descriptor's shouldDisableCacheHits setting when querying on the cache. </lu>

  getDistinctState

  public short getDistinctState()
  

  ADVANCED: If a distinct has been set the DISTINCT clause will be printed. This is used internally by TopLink for batch reading but may also be used directly for advanced queries or report queries.

  getExampleObject

  public java.lang.Object getExampleObject()
  

  PUBLIC: This method returns the current example object. The "example" object is an actual domain object, provided by the client, from which an expression is generated. This expression is used for a query of all objects from the same class, that match the attribute values of the "example" object.

  getExpressionBuilder

  public ExpressionBuilder getExpressionBuilder()
  

  REQUIRED: Get the expression builder which should be used for this query. This expression builder should be used to build all expressions used by this query.

  getInMemoryQueryIndirectionPolicy

  public InMemoryQueryIndirectionPolicy getInMemoryQueryIndirectionPolicy()
  

  PUBLIC: Returns the InMemoryQueryIndirectionPolicy for this query

  getLockMode

  public short getLockMode()
  

  PUBLIC: Return the current locking mode.

  getQueryByExamplePolicy

  public QueryByExamplePolicy getQueryByExamplePolicy()
  

  PUBLIC: When using Query By Example, an instance of QueryByExamplePolicy is used to customize the query. The policy is useful when special operations are to be used for comparisons (notEqual, lessThan, greaterThan, like etc.), when a certain value is to be ignored, or when dealing with nulls.

  getReferenceClass

  public java.lang.Class getReferenceClass()
  

  PUBLIC: Return the reference class of the query.

  Overrides:

  getReferenceClass in class DatabaseQuery

  hasAsOfClause

  public boolean hasAsOfClause()
  

  PUBLIC: Answers if the domain objects are to be read as of a past time.

  See Also:

  getAsOfClause()

  isLockQuery

  public boolean isLockQuery()
  

  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.

  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.

  isLockQuery

  public boolean isLockQuery(Session session)
  

  ADVANCED: Answers if this query will issue any pessimistic locks.

  If the lock mode is not known (DEFAULT_LOCK_MODE / descriptor specified fine-grained locking) the lock mode will be determined now, to be either LOCK, LOCK_NOWAIT, or NO_LOCK.

  See Also:

  isLockQuery()

  isObjectLevelReadQuery

  public boolean isObjectLevelReadQuery()
  

  PUBLIC: Return if this is an object level read query.

  Overrides:

  isObjectLevelReadQuery in class DatabaseQuery

  refreshIdentityMapResult

  public void refreshIdentityMapResult()
  

  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.

  refreshRemoteIdentityMapResult

  public void refreshRemoteIdentityMapResult()
  

  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.

  resetDistinct

  public void resetDistinct()
  

  ADVANCED: If a distinct has been set the DISTINCT clause will be printed. This is used internally by TopLink for batch reading but may also be used directly for advanced queries or report queries.

  setCacheUsage

  public void setCacheUsage(int cacheUsage)
  

  PUBLIC: Set the cache usage. By default only primary key read object queries will first check the cache before accessing the database. Any query can be configure to query against the cache completely, by key or ignore the cache check.

  Valid values are:

  • DoNotCheckCache - The query does not check the cache but accesses the database, the cache will still be maintain.
  • CheckCacheByExactPrimaryKey - If the query is exactly and only on the object's primary key the cache will be checked.
  • CheckCacheByPrimaryKey - If the query contains the primary key and possible other values the cache will be checked.
  • CheckCacheThenDatabase - The whole cache will be checked to see if there is any object matching the query, if not the database will be accessed.
  • CheckCacheOnly - The whole cache will be checked to see if there is any object matching the query, if not null or an empty collection is returned.
  • ConformResultsAgainstUnitOfWork - The results will be checked againtst the changes within the unit of work and object no longer matching or deleted will be remove, matching new objects will also be added.
  • shouldCheckDescriptorForCacheUsage - This setting functions like CheckCacheByPrimaryKey, except checks the appropriate descriptor's shouldDisableCacheHits setting when querying on the cache. </lu>

    setDistinctState

    public void setDistinctState(short distinctState)
    

    ADVANCED: If a distinct has been set the DISTINCT clause will be printed. This is used internally by TopLink for batch reading but may also be used directly for advanced queries or report queries.

    setExampleObject

    public void setExampleObject(java.lang.Object newExampleObject)
    

    PUBLIC: Set the example object of the query to be the newExampleObject. The example object is used for Query By Example. When doing a Query By Example, an instance of the desired object is created, and the fields are filled with the values that are required in the result set. From these values the corresponding expression is built by TopLink, and the query is executed, returning the set of results.

    If a query already has a selection criteria this criteria and the generated query by example criteria will be conjuncted.

    Once a query is executed you must make an explicit call to setExampleObject if the example object is changed, so the query will know to prepare itself again.

    There is a caution to setting both a selection criteria and an example object: Only in this case if you set the example object again after execution you must then also reset the selection criteria. (This is because after execution the original criteria and Query By Example criteria were fused together, and the former cannot be easily recovered from the now invalid result).

    setInMemoryQueryIndirectionPolicy

    public void setInMemoryQueryIndirectionPolicy(InMemoryQueryIndirectionPolicy inMemoryQueryIndirectionPolicy)
    

    PUBLIC: Set the InMemoryQueryIndirectionPolicy for this query

    setLockMode

    public void setLockMode(short lockMode)
    

    PUBLIC: Sets whether this is a pessimistically locking query.

    • ObjectLevelReadQuery.LOCK: SELECT .... FOR UPDATE issued.
    • ObjectLevelReadQuery.LOCK_NOWAIT: SELECT .... FOR UPDATE NO WAIT issued.
    • ObjectLevelReadQuery.NO_LOCK: no pessimistic locking.
    • ObjectLevelReadQuery.DEFAULT_LOCK_MODE (default) and you have a CMP descriptor: fine grained locking will occur.

    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.

    Example:readAllQuery.setSelectionCriteria(employee.get("address").equal("Ottawa"));

    • LOCK: all employees in Ottawa and all referenced Ottawa addresses will be locked.
    • DEFAULT_LOCK_MODE: if address is a joined attribute, and only address has a pessimistic locking policy, only referenced Ottawa addresses will be locked.

    See Also:

    PessimisticLockingPolicy

    setEJBQLString

    public void setEJBQLString(java.lang.String ejbqlString)
    

    Description copied from class: DatabaseQuery

    PUBLIC: To any user of this object. Set the EJBQL string of the query. If arguments are required in the string they will be preceeded by "?" then the argument number.

    Overrides:

    setEJBQLString in class DatabaseQuery

    setQueryByExamplePolicy

    public void setQueryByExamplePolicy(QueryByExamplePolicy queryByExamplePolicy)
    

    PUBLIC: The QueryByExamplePolicy, is a useful to customize the query when Query By Example is used. The policy will control what attributes should, or should not be included in the query. When dealing with nulls, using specail operations (notEqual, lessThan, like, etc.) for comparison, or chosing to include certain attributes at all times, it is useful to modify the policy accordingly.

    Once a query is executed you must make an explicit call to setQueryByExamplePolicy when changing the policy, so the query will know to prepare itself again.

    There is a caution to setting both a selection criteria and an example object: If you set the policy after execution you must also reset the selection criteria. (This is because after execution the original criteria and Query By Example criteria are fused together, and the former cannot be easily recovered).

    setReferenceClass

    public void setReferenceClass(java.lang.Class aClass)
    

    REQUIRED: Set the reference class for the query.

    setSelectionCriteria

    public void setSelectionCriteria(Expression expression)
    

    Description copied from class: DatabaseQuery

    PUBLIC: To any user of this object. Set the selection criteria of the query. This method be used when dealing with expressions.

    Overrides:

    setSelectionCriteria in class DatabaseQuery

    setShouldRefreshIdentityMapResult

    public void setShouldRefreshIdentityMapResult(boolean shouldRefreshIdentityMapResult)
    

    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.

    setShouldRefreshRemoteIdentityMapResult

    public void setShouldRefreshRemoteIdentityMapResult(boolean shouldRefreshIdentityMapResult)
    

    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.

    setShouldUseExclusiveConnection

    public void setShouldUseExclusiveConnection(boolean shouldUseExclusiveConnection)
    

    ADVANCED: If the user has isolated data and specified that the client session should use an exclusive connection then by setting this condition to true TopLink will ensure that the query is executed through the exclusive connection. This may be required in certain cases. An example being where database security will prevent a query joining to a secure table from returning the correct results when executed through the shared connection.

    shouldCheckCacheOnly

    public boolean shouldCheckCacheOnly()
    

    PUBLIC: Return if cache should be checked.

    shouldCheckDescriptorForCacheUsage

    public boolean shouldCheckDescriptorForCacheUsage()
    

    PUBLIC: Return whether the descriptor's disableCacheHits setting should be checked prior to querying the cache.

    shouldConformResultsInUnitOfWork

    public boolean shouldConformResultsInUnitOfWork()
    

    PUBLIC: Should the results will be checked against the changes within the unit of work and object no longer matching or deleted will be remove, matching new objects will also be added..

    shouldRefreshIdentityMapResult

    public boolean shouldRefreshIdentityMapResult()
    

    PUBLIC: Set to a boolean. When set means refresh the instance variables of referenceObject from the database.

    shouldRefreshRemoteIdentityMapResult

    public boolean shouldRefreshRemoteIdentityMapResult()
    

    PUBLIC: Set to a boolean. When set means refresh the instance variables of referenceObject from the database.

    toString

    public java.lang.String toString()
    

    Overrides:

    toString in class DatabaseQuery

    shouldUseExclusiveConnection

    public boolean shouldUseExclusiveConnection()
    

    ADVANCED: If the user has isolated data and specified that the client session should use an exclusive connection then by setting this condition to true TopLink will ensure that the query is executed through the exclusive connection. This may be required in certain cases. An example being where database security will prevent a query joining to a secure table from returning the correct results when executed through the shared connection.

    setShouldProcessResultsInUnitOfWork

    public void setShouldProcessResultsInUnitOfWork(boolean processResultsInUnitOfWork)
    

    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.

    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.

    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.

    shouldProcessResultsInUnitOfWork

    public boolean shouldProcessResultsInUnitOfWork()
    

    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.

    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.

    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.

    useDistinct

    public void useDistinct()
    

    ADVANCED: If a distinct has been set the DISTINCT clause will be printed. This is used internally by TopLink for batch reading but may also be used directly for advanced queries or report queries.

    hasFetchGroup

    public boolean hasFetchGroup()
    

    Return if a fetch group is set in the query.

    getFetchGroup

    public FetchGroup getFetchGroup()
    

    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).

    setFetchGroup

    public void setFetchGroup(FetchGroup newFetchGroup)
    

    Set a dynamic (use case) fetch group to the query.

    setFetchGroupName

    public void setFetchGroupName(java.lang.String groupName)
    

    Set a descriptor-level pre-defined named fetch group to the query.

    getFetchGroupName

    public java.lang.String getFetchGroupName()
    

    Return the fetch group name set in the query.

    shouldUseDefaultFetchGroup

    public boolean shouldUseDefaultFetchGroup()
    

    Return false if the query does not use the default fetch group defined in the descriptor level.

    setShouldUseDefaultFetchGroup

    public void setShouldUseDefaultFetchGroup(boolean shouldUseDefaultFetchGroup)
    

    Set false if the user does not want to use the default fetch group defined in the descriptor level.