Aggregate

java.lang.Object
- de.grogra.xl.lang.Aggregate

```
public final class Aggregate
extends java.lang.Object
```
An instance of Aggregate is used in aggregate method invocations as specified by the XL programming language. Aggregate methods use such an instance to collect the information about a sequence of values which they need to compute an aggregate value.

Author:

Ole Kniemeyer

Field Summary

Fields
Modifier and Type	Field and Description
`java.lang.Object`	`aval` This field contains the result if the type is a reference type.
`java.lang.Object`	`aval1` This field may be used freely by aggregate methods.
`java.lang.Object`	`aval2` This field may be used freely by aggregate methods.
`java.lang.Object`	`aval3` This field may be used freely by aggregate methods.
`java.lang.Object`	`aval4` This field may be used freely by aggregate methods.
`double`	`dval` This field contains the result if the type is `double`.
`double`	`dval1` This field may be used freely by aggregate methods.
`double`	`dval2` This field may be used freely by aggregate methods.
`double`	`dval3` This field may be used freely by aggregate methods.
`double`	`dval4` This field may be used freely by aggregate methods.
`float`	`fval` This field contains the result if the type is `float`.
`float`	`fval1` This field may be used freely by aggregate methods.
`float`	`fval2` This field may be used freely by aggregate methods.
`float`	`fval3` This field may be used freely by aggregate methods.
`float`	`fval4` This field may be used freely by aggregate methods.
`int`	`ival` This field contains the result if the type is `boolean`, `byte`, `short`, `char`, or `int`.
`int`	`ival1` This field may be used freely by aggregate methods.
`int`	`ival2` This field may be used freely by aggregate methods.
`int`	`ival3` This field may be used freely by aggregate methods.
`int`	`ival4` This field may be used freely by aggregate methods.
`long`	`lval` This field contains the result if the type is `long`.
`long`	`lval1` This field may be used freely by aggregate methods.
`long`	`lval2` This field may be used freely by aggregate methods.
`long`	`lval3` This field may be used freely by aggregate methods.
`long`	`lval4` This field may be used freely by aggregate methods.

Method Summary

Methods
Modifier and Type	Method and Description
`static Aggregate`	`allocate(java.lang.Class type)`
`static java.lang.Object`	`aval(Aggregate a)`
`static double`	`dval(Aggregate a)`
`static float`	`fval(Aggregate a)`
`java.lang.Class`	`getType()` Returns the result type of the aggregation.
`boolean`	`initialize()` Returns `true` the first time it is invoked.
`boolean`	`isFinished()` Returns `true` iff `setFinished()` has been called previously.
`static int`	`ival(Aggregate a)`
`static long`	`lval(Aggregate a)`
`void`	`setFinished()` Sets the `finished`-flags to `true`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - aval
```
public java.lang.Object aval
```
    This field contains the result if the type is a reference type. It has to be of the type returned by getType().
  - aval1
```
public java.lang.Object aval1
```
    This field may be used freely by aggregate methods.
  - aval2
```
public java.lang.Object aval2
```
    This field may be used freely by aggregate methods.
  - aval3
```
public java.lang.Object aval3
```
    This field may be used freely by aggregate methods.
  - aval4
```
public java.lang.Object aval4
```
    This field may be used freely by aggregate methods.
  - dval
```
public double dval
```
    This field contains the result if the type is double.
  - dval1
```
public double dval1
```
    This field may be used freely by aggregate methods.
  - dval2
```
public double dval2
```
    This field may be used freely by aggregate methods.
  - dval3
```
public double dval3
```
    This field may be used freely by aggregate methods.
  - dval4
```
public double dval4
```
    This field may be used freely by aggregate methods.
  - fval
```
public float fval
```
    This field contains the result if the type is float.
  - fval1
```
public float fval1
```
    This field may be used freely by aggregate methods.
  - fval2
```
public float fval2
```
    This field may be used freely by aggregate methods.
  - fval3
```
public float fval3
```
    This field may be used freely by aggregate methods.
  - fval4
```
public float fval4
```
    This field may be used freely by aggregate methods.
  - ival
```
public int ival
```
    This field contains the result if the type is boolean, byte, short, char, or int.
  - ival1
```
public int ival1
```
    This field may be used freely by aggregate methods.
  - ival2
```
public int ival2
```
    This field may be used freely by aggregate methods.
  - ival3
```
public int ival3
```
    This field may be used freely by aggregate methods.
  - ival4
```
public int ival4
```
    This field may be used freely by aggregate methods.
  - lval
```
public long lval
```
    This field contains the result if the type is long.
  - lval1
```
public long lval1
```
    This field may be used freely by aggregate methods.
  - lval2
```
public long lval2
```
    This field may be used freely by aggregate methods.
  - lval3
```
public long lval3
```
    This field may be used freely by aggregate methods.
  - lval4
```
public long lval4
```
    This field may be used freely by aggregate methods.
- Method Detail
  - allocate
```
public static Aggregate allocate(java.lang.Class type)
```
  - aval
```
public static java.lang.Object aval(Aggregate a)
```
  - dval
```
public static double dval(Aggregate a)
```
  - fval
```
public static float fval(Aggregate a)
```
  - getType
```
public java.lang.Class getType()
```
    Returns the result type of the aggregation. This has to be respected by aggregate method implementations which compute aggregate values of reference type.
    
    Returns:
    the result type
    See Also:
    aval
  - initialize
```
public boolean initialize()
```
    Returns true the first time it is invoked. This has to be queried in implementations of aggregate methods to initialize their computation.
    
    Returns:
    true iff this method is invoked the first time for a specific invocation of an aggregate method
  - isFinished
```
public boolean isFinished()
```
    Returns true iff setFinished() has been called previously. This is used for two purposes:
    1. To indicate the aggregate method implementation that no more values are available for aggregation. The aggregate method has to compute the final result and place it in the appropriate field (ival, lval, fval, dval, or aval).
    2. To indicate the invoker of the aggregate method that the computation of the aggregate value has been completed by the aggregate method, even if there are values left for aggregation. E.g., this is the case for a shortcut-implementation of the boolean or where the result is known when the first true-value is encountered. The invoker must not invoke the aggregate method again.
    Returns:
    true iff setFinished() has been called previously
  - ival
```
public static int ival(Aggregate a)
```
  - lval
```
public static long lval(Aggregate a)
```
  - setFinished
```
public void setFinished()
```
    Sets the finished-flags to true.
    
    See Also:
    isFinished()

Class Aggregate

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

aval

aval1

aval2

aval3

aval4

dval

dval1

dval2

dval3

dval4

fval

fval1

fval2

fval3

fval4

ival

ival1

ival2

ival3

ival4

lval

lval1

lval2

lval3

lval4

Method Detail

allocate

aval

dval

fval

getType

initialize

isFinished

ival

lval

setFinished