org.objectweb.medor.filter.lib
Class Count
java.lang.Object
|
+--org.objectweb.medor.filter.lib.BasicUnaryOperator
|
+--org.objectweb.medor.filter.lib.BasicAggregateOperator
|
+--org.objectweb.medor.filter.lib.Count
- All Implemented Interfaces:
- AggregateOperator, java.lang.Cloneable, Cloneable, Expression, Operator, UnaryOperator
- public class Count
- extends BasicAggregateOperator
Count aggregate function.
Count applies to :
- a FieldOperand, which is part of a NestedField.
- a Collection of values (TupleCollection), specifying which Field
is to be aggregated
- a Collection of values (Java Collection)
In the case of Count, it may be that no operand is specified. In this
case, like in SQL (*), the Tuples made of all Fields of the NestedField
are considered.
- Author:
- Alexandre Lefebvre
Fields inherited from interface org.objectweb.medor.filter.api.Operator |
ABS, AND, AVG, BITWIZE, CONCAT, CONDAND, CONDOR, COUNT, DIV, EQUAL, FIRSTLOCATE, GREATER, GREATEREQUAL, IN, INDEXEDLOCATE, LENGTH, LOWER, LOWEREQUAL, MAX, MEMBEROF, MIN, MINUS, MOD, MULT, NAV, NOT, NOTEQUAL, NOTMEMBEROF, OR, PLUS, SQRT, SUBSTRING, SUM, UMINUS |
Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface org.objectweb.medor.api.Cloneable |
clone |
Count
public Count()
Count
public Count(Expression e)
Count
public Count(Expression e,
boolean distinct)
getOperatorString
public java.lang.String getOperatorString()
- Description copied from interface:
Operator
- Returns the String representing the operator in Java
- Returns:
- the String representing the operator in Java
compileExpression
public void compileExpression()
throws TypingException,
MalformedExpressionException
- Description copied from interface:
Expression
- Checks the semantic integrity of an expression.
It checks that all types are compatible and prepare the expression to be
evaluable.It also creates buffers where stores the result. Notes that
when evaluating there is no creation of new objects. This method change
the state of this expression object, it will be evaluable and not
modifiable.
- Throws:
MalformedExpressionException
- if syntax error
TypingException
- when incompatible types error
occures.
evaluate
public void evaluate(ParameterOperand[] pos,
Tuple t)
throws MedorException
- Description copied from interface:
Expression
- It evaluates the expression tree and puts the result into the operand
result.
- Specified by:
evaluate
in interface Expression
- Specified by:
evaluate
in class BasicUnaryOperator
- Parameters:
pos
- a list of ParameterOperandt
- Tuple
- Throws:
MedorException
- if evaluation error
countAll
public boolean countAll()
setCountAll
public void setCountAll()