org.geotools.filter.visitor

Class NullFilterVisitor

Object

NullFilterVisitor

All Implemented Interfaces:

ExpressionVisitor, FilterVisitor

Direct Known Subclasses:

ExtractBoundsFilterVisitor

public abstract class NullFilterVisitor
extends Object
implements FilterVisitor, ExpressionVisitor

Abstract implementation of FilterVisitor simple returns the provided data.

This class can be used as is as a placeholder that does nothing:

 Integer one = (Integer) filter.accepts( NullFilterVisitor.NULL_VISITOR, 1 );
 

The class can also be used as an alternative to DefaultFilterVisitor if you want to only walk part of the data structure:

 FilterVisitor allFids = new NullFilterVisitor(){
     public Object visit( Id filter, Object data ) {
         if( data == null) return null;
         Set set = (Set) data;
         set.addAll(filter.getIDs());
         return set;
     }
 };
 Set set = (Set) myFilter.accept(allFids, new HashSet());
 Set set2 = (Set) myFilter.accept(allFids, null ); // set2 will be null
 

The base class provides implementations for:

• walking And, Or, and Not data structures, returning null at any point will exit early
• a default implementation for every other construct that will return the provided data

Author:

Jody Garnett (Refractions Research)

Field Summary

Fields

Modifier and Type	Field and Description
static NullFilterVisitor	NULL_VISITOR

Constructor Summary

Constructors

Constructor and Description
NullFilterVisitor()

Method Summary

Modifier and Type	Method and Description
Object	visit(Add expression, Object data)
Object	visit(After after, Object data)
Object	visit(And filter, Object data)
Object	visit(AnyInteracts anyInteracts, Object data)
Object	visit(BBOX filter, Object data)
Object	visit(Before before, Object data)
Object	visit(Begins begins, Object data)
Object	visit(BegunBy begunBy, Object data)
Object	visit(Beyond filter, Object data)
Object	visit(Contains filter, Object data)
Object	visit(Crosses filter, Object data)
Object	visit(Disjoint filter, Object data)
Object	visit(Divide expression, Object data)
Object	visit(During during, Object data)
Object	visit(DWithin filter, Object data)
Object	visit(EndedBy endedBy, Object data)
Object	visit(Ends ends, Object data)
Object	visit(Equals filter, Object data)
Object	visit(ExcludeFilter filter, Object data) Visit Filter.EXCLUDE (often used during data structure transformations).
Object	visit(Function expression, Object data)
Object	visit(Id filter, Object data)
Object	visit(IncludeFilter filter, Object data) Visit Filter.INCLUDE (often used during data structure transformations).
Object	visit(Intersects filter, Object data)
Object	visit(Literal expression, Object data)
Object	visit(Meets meets, Object data)
Object	visit(MetBy metBy, Object data)
Object	visit(Multiply expression, Object data)
Object	visit(NativeFilter nativeFilter, Object data)
Object	visit(NilExpression expression, Object data) Used to visit a Expression.NIL, also called for null where an expression is expected.
Object	visit(Not filter, Object data)
Object	visit(Or filter, Object data)
Object	visit(OverlappedBy overlappedBy, Object data)
Object	visit(Overlaps filter, Object data)
Object	visit(PropertyIsBetween filter, Object data)
Object	visit(PropertyIsEqualTo filter, Object data)
Object	visit(PropertyIsGreaterThan filter, Object data)
Object	visit(PropertyIsGreaterThanOrEqualTo filter, Object data)
Object	visit(PropertyIsLessThan filter, Object data)
Object	visit(PropertyIsLessThanOrEqualTo filter, Object data)
Object	visit(PropertyIsLike filter, Object data)
Object	visit(PropertyIsNil filter, Object data)
Object	visit(PropertyIsNotEqualTo filter, Object data)
Object	visit(PropertyIsNull filter, Object data)
Object	visit(PropertyName expression, Object data)
Object	visit(Subtract expression, Object data)
Object	visit(TContains contains, Object data)
Object	visit(TEquals equals, Object data)
Object	visit(Touches filter, Object data)
Object	visit(TOverlaps contains, Object data)
Object	visit(Within filter, Object data)
Object	visitNullFilter(Object data) Used to account for a null filter value.

Methods inherited from class Object

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

Field Detail

NULL_VISITOR

public static NullFilterVisitor NULL_VISITOR

Constructor Detail

NullFilterVisitor

public NullFilterVisitor()

Method Detail

visit

public Object visit(ExcludeFilter filter,
                    Object data)

Description copied from interface: FilterVisitor

Visit Filter.EXCLUDE (often used during data structure transformations).

Specified by:

visit in interface FilterVisitor

Parameters:

filter - Filter.EXCLUDE.

data - Value object provided to visitor

Returns:

subclass supplied

visit

public Object visit(IncludeFilter filter,
                    Object data)

Description copied from interface: FilterVisitor

Visit Filter.INCLUDE (often used during data structure transformations).

Specified by:

visit in interface FilterVisitor

Parameters:

filter - Filter.INCLUDE.

data - Value object provided to visitor

Returns:

subclass supplied

visit

public Object visit(And filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Id filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Not filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Or filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsBetween filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsEqualTo filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsNotEqualTo filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsGreaterThan filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsGreaterThanOrEqualTo filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsLessThan filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsLessThanOrEqualTo filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsLike filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsNull filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(PropertyIsNil filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(BBOX filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Beyond filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Contains filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Crosses filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Disjoint filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(DWithin filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Equals filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Intersects filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Overlaps filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Touches filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Within filter,
                    Object data)

Specified by:

visit in interface FilterVisitor

visitNullFilter

public Object visitNullFilter(Object data)

Description copied from interface: FilterVisitor

Used to account for a null filter value.

This is particularly used during data structure transofrmations, however the use of null is not recommended. Please make use of Filter.NONE and Filter.ALL as placeholder objects that communicate intent.

Specified by:

visitNullFilter in interface FilterVisitor

Parameters:

data - Value object provided to visitor

Returns:

subclass defined

visit

public Object visit(NilExpression expression,
                    Object data)

Description copied from interface: ExpressionVisitor

Used to visit a Expression.NIL, also called for null where an expression is expected.

This is particularly useful when doing data transformations, as an example when using a StyleSymbolizer Expression.NIL can be used to represent the default stroke color.

Specified by:

visit in interface ExpressionVisitor

Returns:

implementation specific

visit

public Object visit(Add expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(Divide expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(Function expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(Literal expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(Multiply expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(PropertyName expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(Subtract expression,
                    Object data)

Specified by:

visit in interface ExpressionVisitor

visit

public Object visit(After after,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(AnyInteracts anyInteracts,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Before before,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Begins begins,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(BegunBy begunBy,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(During during,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(EndedBy endedBy,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Ends ends,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(Meets meets,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(MetBy metBy,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(OverlappedBy overlappedBy,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(TContains contains,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(TEquals equals,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(TOverlaps contains,
                    Object data)

Specified by:

visit in interface FilterVisitor

visit

public Object visit(NativeFilter nativeFilter,
                    Object data)

Specified by:

visit in interface FilterVisitor