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java.lang.Object org.apache.openjpa.kernel.exps.Val org.apache.openjpa.kernel.exps.AggregateVal
abstract class AggregateVal
An aggregate of some value.
Constructor Summary | |
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AggregateVal(Val val)
Constructor. |
Method Summary | |
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void |
acceptVisit(ExpressionVisitor visitor)
Accept a visit from a tree visitor. |
protected Collection |
eval(Collection candidates,
Object orig,
StoreContext ctx,
Object[] params)
Return a list of values resulting from evaluating each given candidate. |
protected Object |
eval(Object candidate,
Object orig,
StoreContext ctx,
Object[] params)
Return this value for the given candidate. |
Class |
getType()
Return the expected type for this value, or Object if
the type is unknown. |
protected abstract Class |
getType(Class c)
Return the type of this aggregate based on the value type. |
boolean |
isAggregate()
Return true if this value is an aggregate. |
protected abstract Object |
operate(Collection os,
Class c)
Aggregate the given values. |
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.kernel.exps.Val |
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evaluate, evaluate, getAlias, getMetaData, getName, getPath, getSelectAs, isVariable, isXPath, setAlias, setMetaData |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public AggregateVal(Val val)
Method Detail |
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public boolean isAggregate()
Value
isAggregate
in interface Value
isAggregate
in class Val
public Class getType()
Value
Object
if
the type is unknown.
public void setImplicitType(Class type)
Value
Object
from Value.getType()
.
protected Object eval(Object candidate, Object orig, StoreContext ctx, Object[] params)
Val
eval
in class Val
protected Collection eval(Collection candidates, Object orig, StoreContext ctx, Object[] params)
Val
#eval(Object,Object,StoreContext,Map)
for
each instance and packs the return value into a new list. Aggregates
should override.
eval
in class Val
protected abstract Class getType(Class c)
protected abstract Object operate(Collection os, Class c)
public void acceptVisit(ExpressionVisitor visitor)
Value
acceptVisit
in interface Value
acceptVisit
in class Val
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