org.eclipse.persistence.queries
Class DoesExistQuery

java.lang.Object
  org.eclipse.persistence.queries.DatabaseQuery
      org.eclipse.persistence.queries.DoesExistQuery

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class DoesExistQuery
extends DatabaseQuery

Purpose: This should only be used by the descriptor, this should not be executed directly. Used to determine if an object resides on the database. DoesExistQuery is normally used to determine whether to make an update or insert statement when writing an object.

Responsibilities: Verify the existence of an object. Used only by a write object query.

See Also:

Serialized Form

Author:

Yvon Lavoie

Since:

TOPLink/Java 1.0

Field Summary

static int	AssumeExistence
static int	AssumeNonExistence
static int	CheckCache
boolean	checkCacheFirst Flag to determine if the cache should be check first in addition to another option.
static int	CheckDatabase
protected boolean	checkDatabaseIfInvalid Flag to determine cache invalidation policy support.
protected int	existencePolicy Flag to determine existence check policy.
protected java.lang.Object	object
protected java.util.Vector	primaryKey Query that is performing the does exist check.

Fields inherited from class org.eclipse.persistence.queries.DatabaseQuery

accessor, argumentFields, arguments, argumentTypeNames, argumentTypes, argumentValues, CascadeAggregateDelete, CascadeAllParts, CascadeByMapping, CascadeDependentParts, cascadePolicy, CascadePrivateParts, descriptor, doNotRedirect, executionSession, flushOnExecute, hintString, isCustomQueryUsed, isExecutionClone, isNativeConnectionRequired, isPrepared, isUserDefined, name, NoCascading, properties, queryMechanism, queryTimeout, redirector, session, sessionName, shouldBindAllParameters, shouldCacheStatement, shouldCloneCall, shouldMaintainCache, shouldPrepare, shouldUseWrapperPolicy, sourceMapping, translationRow

Constructor Summary

DoesExistQuery()
PUBLIC: Initialize the state of the query .

DoesExistQuery(Call call)
PUBLIC: Create a query to check if the object exists.

DoesExistQuery(java.lang.Object object)
PUBLIC: Create a query to check if the object exists.

Method Summary

void	assumeExistenceForDoesExist() PUBLIC: Assume that if the objects primary key does not include null then it must exist.
void	assumeNonExistenceForDoesExist() PUBLIC: Assume that the object does not exist.
void	checkCacheForDoesExist() PUBLIC: Assume that if the objects primary key does not include null and it is in the cache, then is must exist.
void	checkDatabaseForDoesExist() PUBLIC: Perform does exist check on the database through selecting the primary key.
void	checkDescriptor(java.lang.Object object, org.eclipse.persistence.internal.sessions.AbstractSession session) INTERNAL: Ensure that the descriptor has been set.
java.lang.Object	checkEarlyReturn(org.eclipse.persistence.internal.sessions.AbstractSession session, org.eclipse.persistence.internal.sessions.AbstractRecord translationRow) INTERNAL: Check if existence can be determined without going to the database.
java.lang.Object	checkEarlyReturn(java.lang.Object object, java.util.Vector primaryKey, org.eclipse.persistence.internal.sessions.AbstractSession session, org.eclipse.persistence.internal.sessions.AbstractRecord translationRow) INTERNAL: Check if existence can be determined without going to the database.
java.lang.Object	executeDatabaseQuery() INTERNAL: Return if the object exists on the database.
boolean	getCheckCacheFirst() INTERNAL:
boolean	getCheckDatabaseIfInvalid() INTERNAL:
protected org.eclipse.persistence.internal.helper.DatabaseField	getDoesExistField() INTERNAL: Return the write lock field or the first primary key field if not using locking.
int	getExistencePolicy() INTERNAL: Return the existence policy for this existence Query
java.lang.Object	getObject() PUBLIC: Return the object.
java.util.Vector	getPrimaryKey() INTERNAL: Return the primaryKey.
java.lang.Class	getReferenceClass() Return the domain class associated with this query.
java.lang.String	getReferenceClassName() INTERNAL: Return the name of the reference class for this query Note: Although the API is designed to avoid requirement of classes being on the classpath, this is not a user defined query type, so it is ok to access the class.
protected void	prepare() INTERNAL: Prepare the receiver for execution in a session.
void	prepareForExecution() INTERNAL: Prepare the receiver for execution in a session.
void	setCheckCacheFirst(boolean checkCacheFirst) INTERNAL: Sets checkCacheFirst flag.
void	setCheckDatabaseIfInvalid(boolean checkCacheFirst) INTERNAL: Sets checkDatabaseIfInvalid flag.
void	setExistencePolicy(int existencePolicy) INTERNAL: Set if the existence policy, this must be set to one of the constants.
void	setObject(java.lang.Object object) PUBLIC: Set the object.
void	setPrimaryKey(java.util.Vector primaryKey) INTERNAL: Set the primaryKey.
boolean	shouldAssumeExistenceForDoesExist() PUBLIC: Returns true if the does exist check should be based only on whether the primary key of the object is set
boolean	shouldAssumeNonExistenceForDoesExist() PUBLIC: Returns true if the does exist check should assume non existence.
boolean	shouldCheckCacheForDoesExist() PUBLIC: Returns true if the does exist check should be based only on a cache check.
boolean	shouldCheckDatabaseForDoesExist() PUBLIC: Returns true if the does exist check should query the database.

Methods inherited from class org.eclipse.persistence.queries.DatabaseQuery

addArgument, addArgument, addArgument, addArgumentByTypeName, addArgumentValue, addArgumentValues, addCall, addStatement, bindAllParameters, buildArgumentFields, buildSelectionCriteria, cacheStatement, cascadeAllParts, cascadeByMapping, cascadeOnlyDependentParts, cascadePrivateParts, checkDescriptor, checkForCustomQuery, checkPrepare, checkPrepare, clone, clonedQueryExecutionComplete, convertClassNamesToClasses, copyFromQuery, dontBindAllParameters, dontCacheStatement, dontCascadeParts, dontMaintainCache, execute, executeInUnitOfWork, extractRemoteResult, getAccessor, getArguments, getArgumentTypeNames, getArgumentTypes, getArgumentValues, getCall, getCascadePolicy, getDatasourceCall, getDatasourceCalls, getDefaultRedirector, getDescriptor, getDomainClassNounName, getDoNotRedirect, getEJBQLString, getExecutionSession, getFlushOnExecute, getHintString, getJPQLString, getName, getProperties, getProperty, getQueryMechanism, getQueryNounName, getQueryTimeout, getRedirector, getSelectionCriteria, getSensorName, getSession, getSessionName, getShouldBindAllParameters, getSourceMapping, getSQLStatement, getSQLString, getSQLStrings, getTranslatedSQLString, getTranslatedSQLStrings, getTranslationRow, hasAccessor, hasArguments, hasProperties, hasQueryMechanism, hasSessionName, ignoreBindAllParameters, ignoreCacheStatement, isCallQuery, isCascadeOfAggregateDelete, isCustomQueryUsed, isCustomSelectionQuery, isDataModifyQuery, isDataReadQuery, isDefaultPropertiesQuery, isDeleteAllQuery, isDeleteObjectQuery, isDirectReadQuery, isExecutionClone, isExpressionQuery, isInsertObjectQuery, isJPQLCallQuery, isModifyAllQuery, isModifyQuery, isNativeConnectionRequired, isObjectBuildingQuery, isObjectLevelModifyQuery, isObjectLevelReadQuery, isPrepared, isReadAllQuery, isReadObjectQuery, isReadQuery, isReportQuery, isSQLCallQuery, isUpdateAllQuery, isUpdateObjectQuery, isUserDefined, isValueReadQuery, isWriteObjectQuery, maintainCache, prepareCall, prepareCustomQuery, prepareForRemoteExecution, prepareFromQuery, redirectQuery, remoteExecute, remoteExecute, removeProperty, replaceValueHoldersIn, rowFromArguments, setAccessor, setArguments, setArgumentTypeNames, setArgumentTypes, setArgumentValues, setCall, setCascadePolicy, setDatasourceCall, setDescriptor, setDoNotRedirect, setEJBQLString, setExecutionSession, setFlushOnExecute, setHintString, setIsCustomQueryUsed, setIsExecutionClone, setIsNativeConnectionRequired, setIsPrepared, setIsUserDefined, setJPQLString, setName, setProperties, setProperty, setQueryMechanism, setQueryTimeout, setRedirector, setSelectionCriteria, setSession, setSessionName, setShouldBindAllParameters, setShouldBindAllParameters, setShouldCacheStatement, setShouldMaintainCache, setShouldPrepare, setShouldUseWrapperPolicy, setSourceMapping, setSQLStatement, setSQLString, setTranslationRow, shouldBindAllParameters, shouldCacheStatement, shouldCascadeAllParts, shouldCascadeByMapping, shouldCascadeOnlyDependentParts, shouldCascadeParts, shouldCascadePrivateParts, shouldCloneCall, shouldIgnoreBindAllParameters, shouldIgnoreCacheStatement, shouldMaintainCache, shouldPrepare, shouldUseWrapperPolicy, toString

Methods inherited from class java.lang.Object

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

Field Detail

AssumeNonExistence

public static final int AssumeNonExistence

See Also:

Constant Field Values

AssumeExistence

public static final int AssumeExistence

See Also:

Constant Field Values

CheckCache

public static final int CheckCache

See Also:

Constant Field Values

CheckDatabase

public static final int CheckDatabase

See Also:

Constant Field Values

primaryKey

protected java.util.Vector primaryKey

Query that is performing the does exist check.

object

protected java.lang.Object object

existencePolicy

protected int existencePolicy

Flag to determine existence check policy.

checkDatabaseIfInvalid

protected boolean checkDatabaseIfInvalid

Flag to determine cache invalidation policy support. This overrides the CheckCache existence setting if the object is invalid or if the cache cannot be trusted because a flush or DML has occurred. The default is true.

checkCacheFirst

public boolean checkCacheFirst

Flag to determine if the cache should be check first in addition to another option. The default is true;

Constructor Detail

DoesExistQuery

public DoesExistQuery()

PUBLIC: Initialize the state of the query . By default the cache is checked, if non cache is used the descriptor should throw a exception and validate.

DoesExistQuery

public DoesExistQuery(java.lang.Object object)

PUBLIC: Create a query to check if the object exists.

DoesExistQuery

public DoesExistQuery(Call call)

PUBLIC: Create a query to check if the object exists.

Method Detail

assumeExistenceForDoesExist

public void assumeExistenceForDoesExist()

PUBLIC: Assume that if the objects primary key does not include null then it must exist. This may be used if the user's system guarantees that an object with non-null key exists.

assumeNonExistenceForDoesExist

public void assumeNonExistenceForDoesExist()

PUBLIC: Assume that the object does not exist. This may be used if the user's system guarantees objects must always be inserted.

checkCacheForDoesExist

public void checkCacheForDoesExist()

PUBLIC: Assume that if the objects primary key does not include null and it is in the cache, then is must exist. This should only be used if a full identity map is being used, and a new object in the client cannot have been inserted by another client.

checkDatabaseForDoesExist

public void checkDatabaseForDoesExist()

PUBLIC: Perform does exist check on the database through selecting the primary key.

checkEarlyReturn

public java.lang.Object checkEarlyReturn(java.lang.Object object,
                                         java.util.Vector primaryKey,
                                         org.eclipse.persistence.internal.sessions.AbstractSession session,
                                         org.eclipse.persistence.internal.sessions.AbstractRecord translationRow)

INTERNAL: Check if existence can be determined without going to the database. Note that custom query check is not require for does exist as the custom is always used. Used by unit of work, and will return null if checkDatabaseIfInvalid is set and the cachekey is invalidated

checkEarlyReturn

public java.lang.Object checkEarlyReturn(org.eclipse.persistence.internal.sessions.AbstractSession session,
                                         org.eclipse.persistence.internal.sessions.AbstractRecord translationRow)

INTERNAL: Check if existence can be determined without going to the database. Note that custom query check is not require for does exist as the custom is always used.

Overrides:

checkEarlyReturn in class DatabaseQuery

executeDatabaseQuery

public java.lang.Object executeDatabaseQuery()
                                      throws DatabaseException

INTERNAL: Return if the object exists on the database. This must be a Boolean object to conform with returning an object. If using optimistic locking, check that the value matches.

Specified by:

executeDatabaseQuery in class DatabaseQuery

Returns:

- the result of executing the query.

Throws:

DatabaseException - - an error has occurred on the database.

getDoesExistField

protected org.eclipse.persistence.internal.helper.DatabaseField getDoesExistField()

INTERNAL: Return the write lock field or the first primary key field if not using locking.

getExistencePolicy

public int getExistencePolicy()

INTERNAL: Return the existence policy for this existence Query

getObject

public java.lang.Object getObject()

PUBLIC: Return the object.

getPrimaryKey

public java.util.Vector getPrimaryKey()

INTERNAL: Return the primaryKey.

getReferenceClass

public java.lang.Class getReferenceClass()

Return the domain class associated with this query.

Overrides:

getReferenceClass in class DatabaseQuery

getReferenceClassName

public java.lang.String getReferenceClassName()

INTERNAL: Return the name of the reference class for this query Note: Although the API is designed to avoid requirement of classes being on the classpath, this is not a user defined query type, so it is ok to access the class.

Overrides:

getReferenceClassName in class DatabaseQuery

prepare

protected void prepare()
                throws QueryException

INTERNAL: Prepare the receiver for execution in a session.

Overrides:

prepare in class DatabaseQuery

Throws:

QueryException

checkDescriptor

public void checkDescriptor(java.lang.Object object,
                            org.eclipse.persistence.internal.sessions.AbstractSession session)
                     throws QueryException

INTERNAL: Ensure that the descriptor has been set.

Throws:

QueryException

prepareForExecution

public void prepareForExecution()
                         throws QueryException

INTERNAL: Prepare the receiver for execution in a session.

Overrides:

prepareForExecution in class DatabaseQuery

Throws:

QueryException

setExistencePolicy

public void setExistencePolicy(int existencePolicy)

INTERNAL: Set if the existence policy, this must be set to one of the constants.

setObject

public void setObject(java.lang.Object object)

PUBLIC: Set the object.

setPrimaryKey

public void setPrimaryKey(java.util.Vector primaryKey)

INTERNAL: Set the primaryKey.

shouldAssumeExistenceForDoesExist

public boolean shouldAssumeExistenceForDoesExist()

PUBLIC: Returns true if the does exist check should be based only on whether the primary key of the object is set

shouldAssumeNonExistenceForDoesExist

public boolean shouldAssumeNonExistenceForDoesExist()

PUBLIC: Returns true if the does exist check should assume non existence.

shouldCheckCacheForDoesExist

public boolean shouldCheckCacheForDoesExist()

PUBLIC: Returns true if the does exist check should be based only on a cache check. Default behavior.

shouldCheckDatabaseForDoesExist

public boolean shouldCheckDatabaseForDoesExist()

PUBLIC: Returns true if the does exist check should query the database.

setCheckCacheFirst

public void setCheckCacheFirst(boolean checkCacheFirst)

INTERNAL: Sets checkCacheFirst flag. If true, existence check will first go to the cache. It will then check other options if it is not found in the cache

Parameters:

checkCacheFirst -

getCheckCacheFirst

public boolean getCheckCacheFirst()

INTERNAL:

Parameters:

checkCacheFirst -

setCheckDatabaseIfInvalid

public void setCheckDatabaseIfInvalid(boolean checkCacheFirst)

INTERNAL: Sets checkDatabaseIfInvalid flag. If true, query will go to the database when it finds the object in the cache and it is invalid. This is only valid when it checks the cache, and is true by default

Parameters:

checkDatabaseIfInvalid -

getCheckDatabaseIfInvalid

public boolean getCheckDatabaseIfInvalid()

INTERNAL:

Parameters:

checkDatabaseIfInvalid -