de.grogra.xl.lang
Class Filter

java.lang.Object
  de.grogra.xl.lang.Filter

public final class Filter
extends java.lang.Object

An instance of Filter is used in filter method invocations as specified by the XL programming language. Filter methods use such an instance to store state information which they need to perform the filtering.

Author:

Ole Kniemeyer

Field Summary

boolean	accept An invocation of a filter method has to set this field to indicate whether the invocation has passed the filter or not.
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 filter methods.
java.lang.Object	aval2 This field may be used freely by filter methods.
java.lang.Object	aval3 This field may be used freely by filter methods.
double	dval This field contains the result if the type is double.
double	dval1 This field may be used freely by filter methods.
double	dval2 This field may be used freely by filter methods.
double	dval3 This field may be used freely by filter methods.
float	fval This field contains the result if the type is float.
float	fval1 This field may be used freely by filter methods.
float	fval2 This field may be used freely by filter methods.
float	fval3 This field may be used freely by filter 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 filter methods.
int	ival2 This field may be used freely by filter methods.
int	ival3 This field may be used freely by filter methods.
long	lval This field contains the result if the type is long.
long	lval1 This field may be used freely by filter methods.
long	lval2 This field may be used freely by filter methods.
long	lval3 This field may be used freely by filter methods.

Method Summary

static Filter	allocate(java.lang.Class type)
java.lang.Class	getType() Returns the result type of the filter.
boolean	initialize() Returns true the first time it is invoked.
boolean	isFinished() Returns true iff setFinished() has been called previously.
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

accept

public boolean accept

An invocation of a filter method has to set this field to indicate whether the invocation has passed the filter or not. If this field is set to true, the filter method also has to set the val-field corresponding to the result type to the filtered value. Otherwise, the invocation has not passed the filter.

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 filter methods.

aval2

public java.lang.Object aval2

This field may be used freely by filter methods.

aval3

public java.lang.Object aval3

This field may be used freely by filter 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 filter methods.

dval2

public double dval2

This field may be used freely by filter methods.

dval3

public double dval3

This field may be used freely by filter 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 filter methods.

fval2

public float fval2

This field may be used freely by filter methods.

fval3

public float fval3

This field may be used freely by filter 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 filter methods.

ival2

public int ival2

This field may be used freely by filter methods.

ival3

public int ival3

This field may be used freely by filter 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 filter methods.

lval2

public long lval2

This field may be used freely by filter methods.

lval3

public long lval3

This field may be used freely by filter methods.

Method Detail

allocate

public static Filter allocate(java.lang.Class type)

getType

public java.lang.Class getType()

Returns the result type of the filter. This has to be respected by filter method implementations which compute resulting 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 filter methods to initialize their state.

Returns:

true iff this method is invoked the first time for a specific invocation of a filter method

isFinished

public boolean isFinished()

Returns true iff setFinished() has been called previously. This is used to indicate the invoker of the filter method that it must not invoke the filter method any more, even if there are values left for filtering.

Returns:

true iff setFinished() has been called previously

setFinished

public void setFinished()

Sets the finished-flags to true. This may only be invoked by filter methods.

See Also:

isFinished()