org.eclipse.persistence.internal.queries

Class ExpressionQueryMechanism

java.lang.Object

org.eclipse.persistence.internal.queries.DatabaseQueryMechanism

org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism

org.eclipse.persistence.internal.queries.CallQueryMechanism

org.eclipse.persistence.internal.queries.StatementQueryMechanism

org.eclipse.persistence.internal.queries.ExpressionQueryMechanism

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

JPQLCallQueryMechanism, QueryByExampleMechanism

public class ExpressionQueryMechanism
extends StatementQueryMechanism

Purpose: Mechanism used for all expression read queries. ExpressionQueryInterface understands how to deal with expressions.

Responsibilities: Translates the expression and creates the appropriate SQL statements. Retrieves the data from the database and return the results to the query.

Since:

TOPLink/Java 1.0

Author:

Yvon Lavoie

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ExpressionQueryMechanism()
ExpressionQueryMechanism(DatabaseQuery query) Initialize the state of the query
ExpressionQueryMechanism(DatabaseQuery query, Expression expression) Initialize the state of the query

Method Summary

Modifier and Type	Method and Description
java.util.Vector	aliasPresetFields(SQLSelectStatement statement) If the fields in the statement have breen pre-set, e.g.
Expression	buildBaseSelectionCriteria(boolean isSubSelect, java.util.Map clonedExpressions) Create the appropriate where clause.
Expression	buildBaseSelectionCriteria(boolean isSubSelect, java.util.Map clonedExpressions, boolean shouldUseAdditionalJoinExpression) Create the appropriate where clause.
SQLSelectStatement	buildBaseSelectStatement(boolean isSubSelect, java.util.Map clonedExpressions) Return the appropriate select statement containing the fields in the table.
SQLSelectStatement	buildBaseSelectStatement(boolean isSubSelect, java.util.Map clonedExpressions, boolean shouldUseAdditionalJoinExpression) Return the appropriate select statement containing the fields in the table.
java.lang.Object	checkCacheForObject(AbstractRecord translationRow, AbstractSession session) Perform a cache lookup for the query This is only called from read object query.
void	clearStatement() The statement is no longer require after prepare so can be released.
DatabaseQueryMechanism	clone(DatabaseQuery queryClone) Clone the mechanism for the specified query clone.
void	extractStatementFromItem(ReportItem item, java.util.Map clonedExpressions, SQLSelectStatement selectStatement, java.util.Vector fieldExpressions)
ExpressionBuilder	getExpressionBuilder() Return an expression builder which is valid for us
Expression	getSelectionCriteria() Return the selection criteria of the query.
java.util.Vector	getSelectionFields(SQLSelectStatement statement, boolean includeAllSubclassFields) Return the fields required in the select clause.
boolean	isExpressionQueryMechanism() Return true if this is an expression query mechanism.
boolean	isStatementQueryMechanism() Return true if this is a statement query mechanism
void	prepare() Override super to do nothing.
void	prepareCursorSelectAllRows() Pre-build the SQL statement from the expression.
void	prepareDeleteAll() Pre-build the SQL statement from the expression.
void	prepareDeleteObject() Pre-build the SQL statement from the expression.
void	prepareDoesExist(DatabaseField field) Pre-build the SQL statement from the expression.
void	prepareInsertObject() Pre-build the SQL statement from the expression.
void	prepareReportQuerySelectAllRows() Pre-build the SQL statement from the expression.
void	prepareReportQuerySubSelect() Pre-build the SQL statement from the expression.
void	prepareSelectAllRows() Pre-build the SQL statement from the expression.
void	prepareSelectOneRow() Pre-build the SQL statement from the expression.
void	prepareUpdateAll() Pre-build the SQL statement from the expressions.
void	prepareUpdateObject() Pre-build the SQL statement from the expression.
java.util.Vector	selectAllReportQueryRows() INTERNAL Read all rows from the database.
java.util.Vector	selectAllRows() Read all rows from the database.
java.util.Vector	selectAllRowsFromConcreteTable() Read all rows from the database.
java.util.Vector	selectAllRowsFromTable() Read all rows from the database.
AbstractRecord	selectOneRow() Read a single row from the database.
AbstractRecord	selectOneRowFromConcreteTable() Read a single row from the database.
AbstractRecord	selectOneRowFromTable() Read a single row from the database.
void	setSelectionCriteria(Expression expression) Set the selection criteria of the query.

Methods inherited from class org.eclipse.persistence.internal.queries.StatementQueryMechanism

deleteObject, executeNoSelect, getSQLStatement, getSQLStatements, hasMultipleStatements, insertObject, insertObject, isCallQueryMechanism, prepareExecuteNoSelect, prepareExecuteSelect, setSQLStatement, trimFieldsForInsert, updateObject

Methods inherited from class org.eclipse.persistence.internal.queries.CallQueryMechanism

getDatabaseCall, prepareCall, prepareExecute, setCallHasCustomSQLArguments, unprepare, updateForeignKeyFieldBeforeDelete

Methods inherited from class org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism

addCall, cursorSelectAllRows, deleteAll, deleteAllUsingTempTables, execute, executeDeferredCall, executeNoSelectCall, executeSelect, executeSelectCall, getCall, getCalls, hasMultipleCalls, selectResultSet, selectRowForDoesExist, setCall, updateAll, updateAllUsingTempTables

Methods inherited from class org.eclipse.persistence.internal.queries.DatabaseQueryMechanism

buildSelectionCriteria, clone, executeWrite, executeWriteWithChangeSet, getModifyRow, getQuery, insertObjectForWrite, isJPQLCallQueryMechanism, isQueryByExampleMechanism, setQuery, updateObjectForWrite, updateObjectForWriteWithChangeSet

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionQueryMechanism

public ExpressionQueryMechanism()

ExpressionQueryMechanism

public ExpressionQueryMechanism(DatabaseQuery query)

Initialize the state of the query

Parameters:

query - - owner of mechanism

ExpressionQueryMechanism

public ExpressionQueryMechanism(DatabaseQuery query,
                                Expression expression)

Initialize the state of the query

Parameters:

query - - owner of mechanism

expression - - selection criteria

Method Detail

aliasPresetFields

public java.util.Vector aliasPresetFields(SQLSelectStatement statement)

If the fields in the statement have breen pre-set, e.g. for a subset of the fields in a partial attribute read, report query, or just a query for the class indicator, then try to alias those. Right now this just guesses that they're all from the base.

buildBaseSelectionCriteria

public Expression buildBaseSelectionCriteria(boolean isSubSelect,
                                             java.util.Map clonedExpressions)

Create the appropriate where clause. Since this is where the selection criteria gets cloned for the first time (long after the owning query has been) many interesting things happen here.

buildBaseSelectionCriteria

public Expression buildBaseSelectionCriteria(boolean isSubSelect,
                                             java.util.Map clonedExpressions,
                                             boolean shouldUseAdditionalJoinExpression)

Create the appropriate where clause. Since this is where the selection criteria gets cloned for the first time (long after the owning query has been) many interesting things happen here. Ability to switch off AdditionalJoinExpression is required for DeleteAllQuery.

buildBaseSelectStatement

public SQLSelectStatement buildBaseSelectStatement(boolean isSubSelect,
                                                   java.util.Map clonedExpressions)

Return the appropriate select statement containing the fields in the table.

buildBaseSelectStatement

public SQLSelectStatement buildBaseSelectStatement(boolean isSubSelect,
                                                   java.util.Map clonedExpressions,
                                                   boolean shouldUseAdditionalJoinExpression)

Return the appropriate select statement containing the fields in the table. Ability to switch off AdditionalJoinExpression is required for DeleteAllQuery.

extractStatementFromItem

public void extractStatementFromItem(ReportItem item,
                                     java.util.Map clonedExpressions,
                                     SQLSelectStatement selectStatement,
                                     java.util.Vector fieldExpressions)

checkCacheForObject

public java.lang.Object checkCacheForObject(AbstractRecord translationRow,
                                            AbstractSession session)

Perform a cache lookup for the query This is only called from read object query. The query has already checked that the cache should be checked.

Overrides:

checkCacheForObject in class DatabaseQueryMechanism

clearStatement

public void clearStatement()

The statement is no longer require after prepare so can be released.

Overrides:

clearStatement in class StatementQueryMechanism

clone

public DatabaseQueryMechanism clone(DatabaseQuery queryClone)

Clone the mechanism for the specified query clone. Should not try to clone statements.

Overrides:

clone in class StatementQueryMechanism

getExpressionBuilder

public ExpressionBuilder getExpressionBuilder()

Return an expression builder which is valid for us

getSelectionCriteria

public Expression getSelectionCriteria()

Return the selection criteria of the query.

Overrides:

getSelectionCriteria in class StatementQueryMechanism

getSelectionFields

public java.util.Vector getSelectionFields(SQLSelectStatement statement,
                                           boolean includeAllSubclassFields)

Return the fields required in the select clause. This must now be called after normalization, so it will get the aliased fields

isExpressionQueryMechanism

public boolean isExpressionQueryMechanism()

Return true if this is an expression query mechanism.

Overrides:

isExpressionQueryMechanism in class DatabaseQueryMechanism

isStatementQueryMechanism

public boolean isStatementQueryMechanism()

Return true if this is a statement query mechanism

Overrides:

isStatementQueryMechanism in class StatementQueryMechanism

prepare

public void prepare()
             throws QueryException

Override super to do nothing.

Overrides:

prepare in class StatementQueryMechanism

Throws:

QueryException

prepareCursorSelectAllRows

public void prepareCursorSelectAllRows()

Pre-build the SQL statement from the expression.

Overrides:

prepareCursorSelectAllRows in class StatementQueryMechanism

prepareDeleteAll

public void prepareDeleteAll()

Pre-build the SQL statement from the expression.

Overrides:

prepareDeleteAll in class StatementQueryMechanism

prepareDeleteObject

public void prepareDeleteObject()

Pre-build the SQL statement from the expression.

Overrides:

prepareDeleteObject in class StatementQueryMechanism

prepareDoesExist

public void prepareDoesExist(DatabaseField field)

Pre-build the SQL statement from the expression.

Overrides:

prepareDoesExist in class StatementQueryMechanism

prepareInsertObject

public void prepareInsertObject()

Pre-build the SQL statement from the expression.

Overrides:

prepareInsertObject in class StatementQueryMechanism

prepareReportQuerySelectAllRows

public void prepareReportQuerySelectAllRows()

Pre-build the SQL statement from the expression.

Overrides:

prepareReportQuerySelectAllRows in class DatasourceCallQueryMechanism

prepareReportQuerySubSelect

public void prepareReportQuerySubSelect()

Pre-build the SQL statement from the expression. This is used for subselects, so does not normalize or generate the SQL as it needs the outer expression for this.

Overrides:

prepareReportQuerySubSelect in class DatasourceCallQueryMechanism

prepareSelectAllRows

public void prepareSelectAllRows()

Pre-build the SQL statement from the expression.

Overrides:

prepareSelectAllRows in class StatementQueryMechanism

prepareSelectOneRow

public void prepareSelectOneRow()

Pre-build the SQL statement from the expression.

Overrides:

prepareSelectOneRow in class StatementQueryMechanism

prepareUpdateObject

public void prepareUpdateObject()

Pre-build the SQL statement from the expression.

Overrides:

prepareUpdateObject in class StatementQueryMechanism

prepareUpdateAll

public void prepareUpdateAll()

Pre-build the SQL statement from the expressions.

Overrides:

prepareUpdateAll in class StatementQueryMechanism

selectAllReportQueryRows

public java.util.Vector selectAllReportQueryRows()
                                          throws DatabaseException

INTERNAL Read all rows from the database. The code to retrieve the full inheritance hierarchy was removed.

Overrides:

selectAllReportQueryRows in class DatasourceCallQueryMechanism

Returns:

Vector containing the database rows.

Throws:

DatabaseException - - an error has occurred on the database.

selectAllRows

public java.util.Vector selectAllRows()
                               throws DatabaseException

Read all rows from the database.

Overrides:

selectAllRows in class DatasourceCallQueryMechanism

Returns:

Vector containing the database rows.

Throws:

DatabaseException - - an error has occurred on the database.

selectAllRowsFromConcreteTable

public java.util.Vector selectAllRowsFromConcreteTable()
                                                throws DatabaseException

Read all rows from the database. This is used only from query mechanism on a abstract-multiple table read.

Throws:

DatabaseException

selectAllRowsFromTable

public java.util.Vector selectAllRowsFromTable()
                                        throws DatabaseException

Read all rows from the database.

Returns:

Vector containing the database rows.

Throws:

DatabaseException - - an error has occurred on the database.

selectOneRow

public AbstractRecord selectOneRow()
                            throws DatabaseException

Read a single row from the database. Create an SQL statement object, use it to create an SQL command string, and delegate row building responsibility to the accessor.

Overrides:

selectOneRow in class DatasourceCallQueryMechanism

Returns:

row containing data

Throws:

DatabaseException - - an error has occurred on the database

selectOneRowFromConcreteTable

public AbstractRecord selectOneRowFromConcreteTable()
                                             throws DatabaseException

Read a single row from the database. This is used from query mechanism during an abstract-multiple table read.

Throws:

DatabaseException

selectOneRowFromTable

public AbstractRecord selectOneRowFromTable()
                                     throws DatabaseException

Read a single row from the database. Create an SQL statement object, use it to create an SQL command string, and delegate row building responsibility to the accessor.

Throws:

DatabaseException

setSelectionCriteria

public void setSelectionCriteria(Expression expression)

Set the selection criteria of the query.