Package org.yamcs.yarch.streamsql

Class AggregateExpression

java.lang.Object

org.yamcs.yarch.streamsql.Expression

org.yamcs.yarch.streamsql.AggregateExpression

Direct Known Subclasses:

AggregateListExpression, CompilableAggregateExpression, FirstValExpression

public abstract class AggregateExpression
extends Expression

Expressions containing aggregates are computed in two phases: phase 1: the input tuples are passed to a list of expressions composed by the group by columns and the list of aggregates phase 2: the output tuples of phase 1 are passed to the list of original select list. In this phase, aggregates act as a ColumnExpression

Field Summary

Fields inherited from class org.yamcs.yarch.streamsql.Expression

children, constantValue, hasAggregates, inputDef, type

Constructor Summary

Constructors

Constructor	Description
AggregateExpression(Expression[] args, boolean star)

Method Summary

Modifier and Type	Method	Description
void	bind(TupleDefinition def)
void	bindAggregate(TupleDefinition def)	When this is called, all the children are already bound.
CompiledExpression	compile()
void	fillCode_getValueReturn(StringBuilder code)
abstract CompiledAggregateExpression	getCompiledAggregate()
protected boolean	isAggregate()

Methods inherited from class org.yamcs.yarch.streamsql.Expression

addFilter, collectAggregates, doBind, fillCode_AllInputDefVars, fillCode_Constructor, fillCode_Declarations, fillCode_getValueBody, getColumnName, getConstantValue, getType, isConstant, setColumnName

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregateExpression

public AggregateExpression(Expression[] args,
                           boolean star)
                    throws ParseException

Throws:

ParseException

Method Detail

isAggregate

protected boolean isAggregate()

Overrides:

isAggregate in class Expression

bindAggregate

public void bindAggregate(TupleDefinition def)
                   throws StreamSqlException

When this is called, all the children are already bound.

Throws:

StreamSqlException

bind

public void bind(TupleDefinition def)
          throws StreamSqlException

Overrides:

bind in class Expression

Throws:

StreamSqlException

fillCode_getValueReturn

public void fillCode_getValueReturn(StringBuilder code)
                             throws StreamSqlException

Specified by:

fillCode_getValueReturn in class Expression

Throws:

StreamSqlException

compile

public CompiledExpression compile()
                           throws StreamSqlException

Overrides:

compile in class Expression

Throws:

StreamSqlException

getCompiledAggregate

public abstract CompiledAggregateExpression getCompiledAggregate()
                                                          throws StreamSqlException

Throws:

StreamSqlException