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

java.lang.Object
  extended by org.apache.openjpa.jdbc.kernel.exps.AbstractVal
      extended by org.apache.openjpa.jdbc.kernel.exps.Aggregate
All Implemented Interfaces:
Serializable, Val, Value

 class Aggregate
extends AbstractVal

Aggregate listener that evaluates to a value.

Author:
Abe White

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
Aggregate(JDBCAggregateListener listener, Val arg, ClassMapping candidate)
          Constructor.
 
Method Summary
 void acceptVisit(ExpressionVisitor visitor)
          Accept a visit from a tree visitor.
 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.
 ClassMetaData getMetaData()
          Return any associated persistent type.
 Class getType()
          Return the expected type for this value, or Object if the type is unknown.
 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.
 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 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.
 
Methods inherited from class org.apache.openjpa.jdbc.kernel.exps.AbstractVal
appendIndex, appendIsEmpty, appendIsNotEmpty, appendIsNotNull, appendIsNull, appendSize, appendType, getAlias, getId, getName, getPath, getSelectAs, isVariable, isXPath, setAlias, toDataStoreValue
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Aggregate

public Aggregate(JDBCAggregateListener listener,
                 Val arg,
                 ClassMapping candidate)
Constructor.

Method Detail

getMetaData

public ClassMetaData getMetaData()
Description copied from interface: Value
Return any associated persistent type.


setMetaData

public void setMetaData(ClassMetaData meta)
Description copied from interface: Value
Associate a persistent type with this value.


isAggregate

public boolean isAggregate()
Description copied from interface: Value
Return true if this value is an aggregate.

Specified by:
isAggregate in interface Value
Overrides:
isAggregate in class AbstractVal

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().


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.


select

public void select(Select sel,
                   ExpContext ctx,
                   ExpState state,
                   boolean pks)
Description copied from interface: Val
Select the data for this value.


selectColumns

public void selectColumns(Select sel,
                          ExpContext ctx,
                          ExpState state,
                          boolean pks)
Description copied from interface: Val
Select just the columns for this value.


groupBy

public void groupBy(Select sel,
                    ExpContext ctx,
                    ExpState state)
Description copied from interface: Val
Group by this value.


orderBy

public void orderBy(Select sel,
                    ExpContext ctx,
                    ExpState state,
                    boolean asc)
Description copied from interface: Val
Order by this value.


load

public Object load(ExpContext ctx,
                   ExpState state,
                   Result res)
            throws SQLException
Description copied from interface: Val
Load the data for this value.

Throws:
SQLException

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.

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

length

public int length(Select sel,
                  ExpContext ctx,
                  ExpState state)
Description copied from interface: Val
Return the number of SQL elements in this value.


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.


acceptVisit

public void acceptVisit(ExpressionVisitor visitor)
Description copied from interface: Value
Accept a visit from a tree visitor.

Specified by:
acceptVisit in interface Value
Overrides:
acceptVisit in class AbstractVal


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