org.apache.openjpa.jdbc.kernel.exps
Class Null
java.lang.Object
   org.apache.openjpa.jdbc.kernel.exps.AbstractVal
org.apache.openjpa.jdbc.kernel.exps.AbstractVal
       org.apache.openjpa.jdbc.kernel.exps.Const
org.apache.openjpa.jdbc.kernel.exps.Const
           org.apache.openjpa.jdbc.kernel.exps.Null
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
 
 
 
 
| 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
 Objectif
 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 | 
 
Null
public Null()
getType
public Class getType()
- Description copied from interface: Value
- Return the expected type for this value, or Objectif
 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
 ObjectfromValue.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 lengthor anyappendmethods.
 
- 
- Specified by:
- calculateValuein interface- Val
- Overrides:
- calculateValuein 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.
 
- 
 
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