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

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

All Implemented Interfaces:

Serializable, Val, Constant, Value

public class Null
extends Const

A literal null value in a filter.

Author:

Abe White

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.openjpa.jdbc.kernel.exps.Const

Const.ConstExpState

Field Summary

Fields inherited from class org.apache.openjpa.jdbc.kernel.exps.AbstractVal

FALSE, 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	appendTo(Select sel, ExpContext ctx, ExpState state, SQLBuffer sql, int index) Append the indexth SQL element to the given buffer.
void	calculateValue(Select sel, ExpContext ctx, ExpState state, Val other, ExpState otherState) Calculate and cache the SQL for this value.
Class	getType() Return the expected type for this value, or Object if the type is unknown.
Object	getValue(Object[] params) Return the value for this constant given the specified parameters.
void	setImplicitType(Class type) Set the implicit type of the value, based on how it is used in the filter.

Methods inherited from class org.apache.openjpa.jdbc.kernel.exps.Const

appendIsEmpty, appendIsNotEmpty, appendIsNotNull, appendIsNull, appendSize, getMetaData, getSQLValue, getValue, groupBy, initialize, isSQLValueNull, length, load, orderBy, select, selectColumns, setMetaData

Methods inherited from class org.apache.openjpa.jdbc.kernel.exps.AbstractVal

acceptVisit, appendIndex, appendType, getAlias, getId, getName, getPath, getSelectAs, isAggregate, isVariable, isXPath, setAlias, toDataStoreValue

Methods inherited from class java.lang.Object

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

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

Overrides:

calculateValue in class Const

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.