org.apache.cayenne.access.trans
Class QualifierTranslator

java.lang.Object
  org.apache.cayenne.access.trans.QueryAssemblerHelper
      org.apache.cayenne.access.trans.QualifierTranslator

All Implemented Interfaces:

TraversalHandler

Direct Known Subclasses:

OpenBaseQualifierTranslator, TrimmingQualifierTranslator

public class QualifierTranslator
extends QueryAssemblerHelper
implements TraversalHandler

Translates query qualifier to SQL. Used as a helper class by query translators.

Author:

Andrei Adamchik

Field Summary

protected boolean	matchingObject
protected DataObjectMatchTranslator	objectMatchTranslator
protected java.lang.StringBuffer	qualBuf
protected boolean	translateParentQual

Fields inherited from class org.apache.cayenne.access.trans.QueryAssemblerHelper

queryAssembler

Constructor Summary

QualifierTranslator()

QualifierTranslator(QueryAssembler queryAssembler)

Method Summary

protected void	appendLiteral(java.lang.StringBuffer buf, java.lang.Object val, DbAttribute attr, Expression parentExpression) Appends SQL code to the query buffer to handle val as a parameter to the PreparedStatement being built.
protected void	appendObjectMatch()
protected void	detectObjectMatch(Expression exp) Called before processing an expression to initialize objectMatchTranslator if needed.
java.lang.String	doTranslation() Translates query qualifier to SQL WHERE clause.
void	endNode(Expression node, Expression parentNode) Called during the traversal after an expression node children processing is finished.
protected Expression	extractQualifier()
void	finishedChild(Expression node, int childIndex, boolean hasMoreChildren) Opportunity to insert an operation
ObjEntity	getObjEntity()
boolean	isTranslateParentQual() Returns true if this translator will translate parent qualifier on call to doTranslation.
void	objectNode(java.lang.Object leaf, Expression parentNode) Called during the traversal when a leaf non-expression node is encountered.
protected boolean	parenthesisNeeded(Expression node, Expression parentNode)
protected void	processRelTermination(java.lang.StringBuffer buf, DbRelationship rel) Handles case when a DB_NAME expression ends with relationship.
void	setTranslateParentQual(boolean translateParentQual) Configures translator to translate parent or main qualifier on call to doTranslation.
void	startNode(Expression node, Expression parentNode) Called during the traversal before an expression node children processing is started.

Methods inherited from class org.apache.cayenne.access.trans.QueryAssemblerHelper

appendDbPath, appendLiteralDirect, appendObjPath, getDbEntity, getQueryAssembler, paramsDbType, processColumn, processColumn, processColumn, processRelTermination, setQueryAssembler

Methods inherited from class java.lang.Object

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

Field Detail

qualBuf

protected java.lang.StringBuffer qualBuf

translateParentQual

protected boolean translateParentQual

objectMatchTranslator

protected DataObjectMatchTranslator objectMatchTranslator

matchingObject

protected boolean matchingObject

Constructor Detail

QualifierTranslator

public QualifierTranslator()

QualifierTranslator

public QualifierTranslator(QueryAssembler queryAssembler)

Method Detail

doTranslation

public java.lang.String doTranslation()

Translates query qualifier to SQL WHERE clause. Qualifier is obtained from queryAssembler object.

Specified by:

doTranslation in class QueryAssemblerHelper

extractQualifier

protected Expression extractQualifier()

detectObjectMatch

protected void detectObjectMatch(Expression exp)

Called before processing an expression to initialize objectMatchTranslator if needed.

appendObjectMatch

protected void appendObjectMatch()

finishedChild

public void finishedChild(Expression node,
                          int childIndex,
                          boolean hasMoreChildren)

Opportunity to insert an operation

Specified by:

finishedChild in interface TraversalHandler

startNode

public void startNode(Expression node,
                      Expression parentNode)

Description copied from interface: TraversalHandler

Called during the traversal before an expression node children processing is started.

Specified by:

startNode in interface TraversalHandler

endNode

public void endNode(Expression node,
                    Expression parentNode)

Description copied from interface: TraversalHandler

Called during the traversal after an expression node children processing is finished.

Specified by:

endNode in interface TraversalHandler

Since:

1.1

objectNode

public void objectNode(java.lang.Object leaf,
                       Expression parentNode)

Description copied from interface: TraversalHandler

Called during the traversal when a leaf non-expression node is encountered.

Specified by:

objectNode in interface TraversalHandler

parenthesisNeeded

protected boolean parenthesisNeeded(Expression node,
                                    Expression parentNode)

isTranslateParentQual

public boolean isTranslateParentQual()

Returns true if this translator will translate parent qualifier on call to doTranslation.

Returns:

boolean

setTranslateParentQual

public void setTranslateParentQual(boolean translateParentQual)

Configures translator to translate parent or main qualifier on call to doTranslation.

Parameters:

translateParentQual - The translateParentQual to set

getObjEntity

public ObjEntity getObjEntity()

Overrides:

getObjEntity in class QueryAssemblerHelper

appendLiteral

protected void appendLiteral(java.lang.StringBuffer buf,
                             java.lang.Object val,
                             DbAttribute attr,
                             Expression parentExpression)

Description copied from class: QueryAssemblerHelper

Appends SQL code to the query buffer to handle val as a parameter to the PreparedStatement being built. Adds val into QueryAssembler parameter list.

If val is null, "NULL" is appended to the query.

If val is a DataObject, its primary key value is used as a parameter. Only objects with a single column primary key can be used.

Overrides:

appendLiteral in class QueryAssemblerHelper

Parameters:

buf - query buffer.

val - object that should be appended as a literal to the query. Must be of one of "standard JDBC" types, null or a DataObject.

attr - DbAttribute that has information on what type of parameter is being appended.

processRelTermination

protected void processRelTermination(java.lang.StringBuffer buf,
                                     DbRelationship rel)

Description copied from class: QueryAssemblerHelper

Handles case when a DB_NAME expression ends with relationship. If this is a "to many" relationship, a join is added and a column expression for the target entity primary key. If this is a "to one" relationship, column expresion for the source foreign key is added.

Overrides:

processRelTermination in class QueryAssemblerHelper