org.apache.cayenne.access.translator.select

Class SelectTranslator

java.lang.Object

org.apache.cayenne.access.translator.select.QueryAssembler

org.apache.cayenne.access.translator.select.SelectTranslator

Direct Known Subclasses:

IngresSelectTranslator, SQLServerSelectTranslator

public class SelectTranslator
extends QueryAssembler

A builder of JDBC PreparedStatements based on Cayenne SelectQueries. Translates SelectQuery to parameterized SQL string and wraps it in a PreparedStatement. SelectTranslator is stateful and thread-unsafe.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int[]	UNSUPPORTED_DISTINCT_TYPES

Fields inherited from class org.apache.cayenne.access.translator.select.QueryAssembler

adapter, attributes, cachedSqlString, connection, entityResolver, logger, parameterIndex, query, queryMetadata, values

Constructor Summary

Constructors

Constructor and Description
SelectTranslator(Query query, DataNode dataNode, Connection connection)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	appendLimitAndOffsetClauses(StringBuilder buffer) Handles appending optional limit and offset clauses.
protected void	appendSelectColumns(StringBuilder buffer, List<String> selectColumnExpList)
protected List<ColumnDescriptor>	buildResultColumns()
protected JoinStack	createJoinStack()
String	createSqlString() Returns query translated to SQL.
void	dbRelationshipAdded(DbRelationship relationship, JoinType joinType, String joinSplitAlias) Appends a join with given semantics to the query.
Map<ObjAttribute,ColumnDescriptor>	getAttributeOverrides() Returns a map of ColumnDescriptors keyed by ObjAttribute for columns that may need to be reprocessed manually due to incompatible mappings along the inheritance hierarchy.
String	getCurrentAlias() Returns an alias of the table which is currently at the top of the join stack.
JoinStack	getJoinStack()
ColumnDescriptor[]	getResultColumns() Returns a list of ColumnDescriptors for the query columns.
boolean	isSuppressingDistinct() Returns true if SelectTranslator determined that a query requiring DISTINCT can't be run with DISTINCT keyword for internal reasons.
protected static boolean	isUnsupportedForDistinct(int type)
void	resetJoinStack() A callback invoked by a child qualifier or ordering processor allowing query assembler to reset its join stack.
boolean	supportsTableAliases() Always returns true.

Methods inherited from class org.apache.cayenne.access.translator.select.QueryAssembler

addToParamList, createStatement, getAdapter, getEntityResolver, getJdbcEventLogger, getPathAliases, getQuery, getQueryMetadata, getRootDbEntity, getRootEntity, initStatement

Methods inherited from class java.lang.Object

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

Field Detail

UNSUPPORTED_DISTINCT_TYPES

protected static final int[] UNSUPPORTED_DISTINCT_TYPES

Constructor Detail

SelectTranslator

public SelectTranslator(Query query,
                DataNode dataNode,
                Connection connection)

Since:

4.0

Method Detail

isUnsupportedForDistinct

protected static boolean isUnsupportedForDistinct(int type)

getJoinStack

public JoinStack getJoinStack()

createJoinStack

protected JoinStack createJoinStack()

createSqlString

public String createSqlString()
                       throws Exception

Returns query translated to SQL. This is a main work method of the SelectTranslator.

Specified by:

createSqlString in class QueryAssembler

Throws:

Exception

appendSelectColumns

protected void appendSelectColumns(StringBuilder buffer,
                       List<String> selectColumnExpList)

Since:

3.1

appendLimitAndOffsetClauses

protected void appendLimitAndOffsetClauses(StringBuilder buffer)

Handles appending optional limit and offset clauses. This implementation does nothing, deferring to subclasses to define the LIMIT/OFFSET clause syntax.

Since:

3.0

getCurrentAlias

public String getCurrentAlias()

Description copied from class: QueryAssembler

Returns an alias of the table which is currently at the top of the join stack.

Specified by:

getCurrentAlias in class QueryAssembler

getResultColumns

public ColumnDescriptor[] getResultColumns()

Returns a list of ColumnDescriptors for the query columns.

Since:

1.2

getAttributeOverrides

public Map<ObjAttribute,ColumnDescriptor> getAttributeOverrides()

Returns a map of ColumnDescriptors keyed by ObjAttribute for columns that may need to be reprocessed manually due to incompatible mappings along the inheritance hierarchy.

Since:

1.2

isSuppressingDistinct

public boolean isSuppressingDistinct()

Returns true if SelectTranslator determined that a query requiring DISTINCT can't be run with DISTINCT keyword for internal reasons. If this method returns true, DataNode may need to do in-memory distinct filtering.

Since:

1.1

buildResultColumns

protected List<ColumnDescriptor> buildResultColumns()

resetJoinStack

public void resetJoinStack()

Description copied from class: QueryAssembler

A callback invoked by a child qualifier or ordering processor allowing query assembler to reset its join stack.

Specified by:

resetJoinStack in class QueryAssembler

Since:

3.0

dbRelationshipAdded

public void dbRelationshipAdded(DbRelationship relationship,
                       JoinType joinType,
                       String joinSplitAlias)

Description copied from class: QueryAssembler

Appends a join with given semantics to the query.

Specified by:

dbRelationshipAdded in class QueryAssembler

Since:

3.0

supportsTableAliases

public boolean supportsTableAliases()

Always returns true.

Overrides:

supportsTableAliases in class QueryAssembler