|
|||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
Each instance of IAggregation defines an aggregation which can be used in BIRT. All user defined aggregations should implement this interface.
Field Summary | |
static int |
RUNNING_AGGR
|
static int |
SUMMARY_AGGR
|
Method Summary | |
java.lang.String |
getName()
Gets the name that identifies the aggregate function represented by this class. |
boolean[] |
getParameterDefn()
Gets information about the parameters that this aggregate function takes as an array of boolean values. |
int |
getType()
Gets the type of the Aggregation. |
Accumulator |
newAccumulator()
Creates a new instance of the accumulator for this aggregation. |
Field Detail |
public static final int SUMMARY_AGGR
public static final int RUNNING_AGGR
Method Detail |
public java.lang.String getName()
public int getType()
public boolean[] getParameterDefn()
The length of the returned array is the number of runtime parameters that this aggregate function takes. Note that this number excludes the optional filter and group parameters common to all aggregate functions. Those two parameters are handled by the DtE.
If the n'th element in the array is true, it means that the n'th parameter is a dynamic parameter which needs to be evaluated at each row. Otherwise the parameter is static, and it only needs to be evaluated once at the start of the accumulation
For example, the Total.movingAve function is defined as
movingAve( expr, window [, filter [, group ]] )
The expr parameter is the data being aggregated over and should be calculated at every row. The
window parameter on the other hand must be a fixed number for each series of data. Therefore the class
implementing the movingAve function should return boolean array [true, false].
public Accumulator newAccumulator()
|
|||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |