org.apache.openjpa.jdbc.kernel.exps
Class Null

java.lang.Object
  org.apache.openjpa.jdbc.kernel.exps.Null

All Implemented Interfaces:

Serializable, Val, Constant, Value

public class Null
extends Object

A literal null value in a filter.

Author:

Abe White

See Also:

Serialized Form

Nested Class Summary

protected static class

Const.ConstExpState Constant expression state.

Field Summary

protected static String	FALSE
protected static String	TRUE

Fields inherited from interface org.apache.openjpa.jdbc.kernel.exps.Val

ABS_VAL, ARGS_VAL, CMP_EQUAL, COALESCE_VAL, CONCAT_VAL, FORCE_OUTER, GENERALCASE_VAL, INDEXOF_VAL, JOIN_REL, LENGTH_VAL, LOCATE_VAL, LOWER_VAL, MATH_VAL, NULL_CMP, NULLIF_VAL, SIMPLECASE_VAL, SQRT_VAL, SUBSTRING_VAL, TRIM_VAL, UPPER_VAL, VAL, WHENCONDITION_VAL, WHENSCALAR_VAL

Constructor Summary

Null()

Method Summary

void	acceptVisit(ExpressionVisitor visitor) Accept a visit from a tree visitor.
void	appendIndex(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL checking the index of this value.
void	appendIsEmpty(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL testing whether this value is empty to the given buffer.
void	appendIsNotEmpty(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL testing whether this value is not empty to the given buffer.
void	appendIsNotNull(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL testing whether this value is not null to the given buffer.
void	appendIsNull(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL testing whether this value is null to the given buffer.
void	appendSize(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL checking the size of this value.
void	appendTo(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql, int index) Append the indexth SQL element to the given buffer.
void	appendType(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql) Append the SQL checking the type of this value.
void	calculateValue(Select sel, ExpContext ctx, ExpState state, Val other, ExpState otherState) Calculate and cache the SQL for this value.
String	getAlias() Return select item alias
int	getId()
ClassMetaData	getMetaData() Return any associated persistent type.
String	getName()
Path	getPath()
Value	getSelectAs() Return 'this' concrete class if alias is set, otherwise null
Object	getSQLValue(Select sel, ExpContext ctx, ExpState state) Return the SQL value of this constant.
Class	getType() Return the expected type for this value, or Object if the type is unknown.
Object	getValue(ExpContext ctx, ExpState state) Return the value of this constant.
Object	getValue(Object[] params) Return the value for this constant given the specified parameters.
void	groupBy(Select sel, ExpContext ctx, ExpState state) Group by this value.
ExpState	initialize(Select sel, ExpContext ctx, int flags) Initialize the value.
boolean	isAggregate() Return true if this value is an aggregate.
boolean	isSQLValueNull(Select sel, ExpContext ctx, ExpState state) Return true if this constant's SQL value is equivalent to NULL.
boolean	isVariable() Return true if this value is a variable.
boolean	isXPath() Return true if this value is an XML Path.
int	length(Select sel, ExpContext ctx, ExpState state) Return the number of SQL elements in this value.
Object	load(ExpContext ctx, ExpState state, Result res) Load the data for this value.
void	orderBy(Select sel, ExpContext ctx, ExpState state, boolean asc) Order by this value.
void	select(Select sel, ExpContext ctx, ExpState state, boolean pks) Select the data for this value.
void	selectColumns(Select sel, ExpContext ctx, ExpState state, boolean pks) Select just the columns for this value.
void	setAlias(String alias) Set select item alias
void	setImplicitType(Class type) Set the implicit type of the value, based on how it is used in the filter.
void	setMetaData(ClassMetaData meta) Associate a persistent type with this value.
Object	toDataStoreValue(Select sel, ExpContext ctx, ExpState state, Object val) Return the datastore value of the given object in the context of this value.

Methods inherited from class java.lang.Object

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

Field Detail

TRUE

protected static final String TRUE

See Also:

Constant Field Values

FALSE

protected static final String FALSE

See Also:

Constant Field Values

Constructor Detail

Null

public Null()

Method Detail

getType

public Class getType()

Description copied from interface: Value

Return the expected type for this value, or Object if the type is unknown.

setImplicitType

public void setImplicitType(Class type)

Description copied from interface: Value

Set the implicit type of the value, based on how it is used in the filter. This method is only called on values who return Object from Value.getType().

getValue

public Object getValue(Object[] params)

Description copied from interface: Constant

Return the value for this constant given the specified parameters.

calculateValue

public void calculateValue(Select sel,
                           ExpContext ctx,
                           ExpState state,
                           Val other,
                           ExpState otherState)

Description copied from interface: Val

Calculate and cache the SQL for this value. This method is called before length or any append methods.

Specified by:

calculateValue in interface Val

other - the value being compared to, or null if not a comparison

appendTo

public void appendTo(Select sel,
                     ExpContext ctx,
                     ExpState state,
                     SQLBuffer sql,
                     int index)

Description copied from interface: Val

Append the indexth SQL element to the given buffer.

getMetaData

public ClassMetaData getMetaData()

Description copied from interface: Value

Return any associated persistent type.

Specified by:

getMetaData in interface Value

setMetaData

public void setMetaData(ClassMetaData meta)

Description copied from interface: Value

Associate a persistent type with this value.

Specified by:

setMetaData in interface Value

getSQLValue

public Object getSQLValue(Select sel,
                          ExpContext ctx,
                          ExpState state)

Return the SQL value of this constant.

isSQLValueNull

public boolean isSQLValueNull(Select sel,
                              ExpContext ctx,
                              ExpState state)

Return true if this constant's SQL value is equivalent to NULL.

getValue

public Object getValue(ExpContext ctx,
                       ExpState state)

Return the value of this constant. May be more robust than the parameters-only form.

initialize

public ExpState initialize(Select sel,
                           ExpContext ctx,
                           int flags)

Description copied from interface: Val

Initialize the value. This method should recursively initialize any sub-values.

Specified by:

initialize in interface Val

select

public void select(Select sel,
                   ExpContext ctx,
                   ExpState state,
                   boolean pks)

Description copied from interface: Val

Select the data for this value.

Specified by:

select in interface Val

selectColumns

public void selectColumns(Select sel,
                          ExpContext ctx,
                          ExpState state,
                          boolean pks)

Description copied from interface: Val

Select just the columns for this value.

Specified by:

selectColumns in interface Val

groupBy

public void groupBy(Select sel,
                    ExpContext ctx,
                    ExpState state)

Description copied from interface: Val

Group by this value.

Specified by:

groupBy in interface Val

orderBy

public void orderBy(Select sel,
                    ExpContext ctx,
                    ExpState state,
                    boolean asc)

Description copied from interface: Val

Order by this value.

Specified by:

orderBy in interface Val

load

public Object load(ExpContext ctx,
                   ExpState state,
                   Result res)
            throws SQLException

Description copied from interface: Val

Load the data for this value.

Specified by:

load in interface Val

Throws:

SQLException

length

public int length(Select sel,
                  ExpContext ctx,
                  ExpState state)

Description copied from interface: Val

Return the number of SQL elements in this value.

Specified by:

length in interface Val

appendIsEmpty

public void appendIsEmpty(Select sel,
                          ExpContext ctx,
                          ExpState state,
                          SQLBuffer sql)

Description copied from interface: Val

Append the SQL testing whether this value is empty to the given buffer.

Specified by:

appendIsEmpty in interface Val

appendIsNotEmpty

public void appendIsNotEmpty(Select sel,
                             ExpContext ctx,
                             ExpState state,
                             SQLBuffer sql)

Description copied from interface: Val

Append the SQL testing whether this value is not empty to the given buffer.

Specified by:

appendIsNotEmpty in interface Val

appendSize

public void appendSize(Select sel,
                       ExpContext ctx,
                       ExpState state,
                       SQLBuffer sql)

Description copied from interface: Val

Append the SQL checking the size of this value.

Specified by:

appendSize in interface Val

appendIsNull

public void appendIsNull(Select sel,
                         ExpContext ctx,
                         ExpState state,
                         SQLBuffer sql)

Description copied from interface: Val

Append the SQL testing whether this value is null to the given buffer.

Specified by:

appendIsNull in interface Val

appendIsNotNull

public void appendIsNotNull(Select sel,
                            ExpContext ctx,
                            ExpState state,
                            SQLBuffer sql)

Description copied from interface: Val

Append the SQL testing whether this value is not null to the given buffer.

Specified by:

appendIsNotNull in interface Val

isVariable

public boolean isVariable()

Description copied from interface: Value

Return true if this value is a variable.

Specified by:

isVariable in interface Value

isAggregate

public boolean isAggregate()

Description copied from interface: Value

Return true if this value is an aggregate.

Specified by:

isAggregate in interface Value

isXPath

public boolean isXPath()

Description copied from interface: Value

Return true if this value is an XML Path.

Specified by:

isXPath in interface Value

toDataStoreValue

public Object toDataStoreValue(Select sel,
                               ExpContext ctx,
                               ExpState state,
                               Object val)

Description copied from interface: Val

Return the datastore value of the given object in the context of this value.

Specified by:

toDataStoreValue in interface Val

appendIndex

public void appendIndex(Select sel,
                        ExpContext ctx,
                        ExpState state,
                        SQLBuffer sql)

Description copied from interface: Val

Append the SQL checking the index of this value.

Specified by:

appendIndex in interface Val

appendType

public void appendType(Select sel,
                       ExpContext ctx,
                       ExpState state,
                       SQLBuffer sql)

Description copied from interface: Val

Append the SQL checking the type of this value.

Specified by:

appendType in interface Val

acceptVisit

public void acceptVisit(ExpressionVisitor visitor)

Description copied from interface: Value

Accept a visit from a tree visitor.

Specified by:

acceptVisit in interface Value

getId

public int getId()

Specified by:

getId in interface Val

getAlias

public String getAlias()

Description copied from interface: Value

Return select item alias

Specified by:

getAlias in interface Value

setAlias

public void setAlias(String alias)

Description copied from interface: Value

Set select item alias

Specified by:

setAlias in interface Value

getSelectAs

public Value getSelectAs()

Description copied from interface: Value

Return 'this' concrete class if alias is set, otherwise null

Specified by:

getSelectAs in interface Val

Specified by:

getSelectAs in interface Value

getPath

public Path getPath()

Specified by:

getPath in interface Value

getName

public String getName()

Specified by:

getName in interface Value