UniqueVisitor (Geotools modules 27-SNAPSHOT API)

Object
- UniqueVisitor

All Implemented Interfaces:

FeatureAttributeVisitor, FeatureCalc, LimitingVisitor, FeatureVisitor

Direct Known Subclasses:

UniqueCountVisitor
```
public class UniqueVisitor
extends Object
implements FeatureCalc, FeatureAttributeVisitor, LimitingVisitor
```
Generates a list of unique values from a collection

Since:

2.2.M2

Author:

Cory Horner, Refractions

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class UniqueVisitor.UniqueResult

Nested Classes
Modifier and Type	Class and Description
`static class`	`UniqueVisitor.UniqueResult`

Constructor Summary

Constructors
Constructor and Description
`UniqueVisitor(Expression expr)`
`UniqueVisitor(int attributeTypeIndex, SimpleFeatureType type)`
`UniqueVisitor(String attributeTypeName)`
`UniqueVisitor(String attrName, SimpleFeatureType type)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Expression`	`getExpression()`
`List<Expression>`	`getExpressions()` List of expressions used by visitor.
`int`	`getMaxFeatures()` Returns maxFeatures (max # of elements to return)
`CalcResult`	`getResult()` Returns the result of the calculation as a handy object which can be merged and modified.
`Optional<List<Class>>`	`getResultType(List<Class> inputTypes)` Returns the expected output type given the input type.
`int`	`getStartIndex()` Returns startIndex (first element to return)
`Set`	`getUnique()`
`boolean`	`hasLimits()` Checks if the visitor has limits.
`void`	`init(SimpleFeatureCollection collection)`
`boolean`	`isPreserveOrder()` True if the unique visitor must be order preserving
`void`	`reset()`
`void`	`setMaxFeatures(int maxFeatures)`
`void`	`setPreserveOrder(boolean preserveOrder)`
`void`	`setStartIndex(int startIndex)`
`void`	`setValue(Object newSet)`
`void`	`visit(Feature feature)` Visit the provided feature.
`void`	`visit(SimpleFeature feature)`

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

- Constructor Detail
  - UniqueVisitor
```
public UniqueVisitor(String attributeTypeName)
```
  - UniqueVisitor
```
public UniqueVisitor(int attributeTypeIndex,
                     SimpleFeatureType type)
              throws IllegalFilterException
```
    Throws:
    
    IllegalFilterException
  - UniqueVisitor
```
public UniqueVisitor(String attrName,
                     SimpleFeatureType type)
              throws IllegalFilterException
```
    Throws:
    
    IllegalFilterException
  - UniqueVisitor
```
public UniqueVisitor(Expression expr)
```
- Method Detail
  - init
```
public void init(SimpleFeatureCollection collection)
```
  - setStartIndex
```
public void setStartIndex(int startIndex)
```
  - setMaxFeatures
```
public void setMaxFeatures(int maxFeatures)
```
  - setPreserveOrder
```
public void setPreserveOrder(boolean preserveOrder)
```
  - getStartIndex
```
public int getStartIndex()
```
    Description copied from interface: LimitingVisitor
    
    Returns startIndex (first element to return)
    
    Specified by:
    
    getStartIndex in interface LimitingVisitor
  - getMaxFeatures
```
public int getMaxFeatures()
```
    Description copied from interface: LimitingVisitor
    
    Returns maxFeatures (max # of elements to return)
    
    Specified by:
    
    getMaxFeatures in interface LimitingVisitor
  - getExpressions
```
public List<Expression> getExpressions()
```
    Description copied from interface: FeatureAttributeVisitor
    
    List of expressions used by visitor.
    
    Specified by:
    
    getExpressions in interface FeatureAttributeVisitor
  - getResultType
```
public Optional<List<Class>> getResultType(List<Class> inputTypes)
```
    Description copied from interface: FeatureAttributeVisitor
    
    Returns the expected output type given the input type.
    
    Specified by:
    
    getResultType in interface FeatureAttributeVisitor
    
    Parameters:
    
    inputTypes - The type of the input expressions
  - visit
```
public void visit(SimpleFeature feature)
```
  - visit
```
public void visit(Feature feature)
```
    Description copied from interface: FeatureVisitor
    
    Visit the provided feature.
    Please consult the documentation for the FeatureCollection you are visiting to learn more - the provided feature may be invalid, or read only.
    
    Specified by:
    
    visit in interface FeatureVisitor
  - getExpression
```
public Expression getExpression()
```
  - getUnique
```
public Set getUnique()
```
  - setValue
```
public void setValue(Object newSet)
```
  - reset
```
public void reset()
```
  - getResult
```
public CalcResult getResult()
```
    Description copied from interface: FeatureCalc
    
    Returns the result of the calculation as a handy object which can be merged and modified.
    
    Specified by:
    
    getResult in interface FeatureCalc
    
    Returns:
    
    the results of the calculation
  - hasLimits
```
public boolean hasLimits()
```
    Description copied from interface: LimitingVisitor
    
    Checks if the visitor has limits.
    
    Specified by:
    
    hasLimits in interface LimitingVisitor
    
    Returns:
    
    true if the visitor has limits
  - isPreserveOrder
```
public boolean isPreserveOrder()
```
    True if the unique visitor must be order preserving

Class UniqueVisitor

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class Object

Constructor Detail

UniqueVisitor

UniqueVisitor

UniqueVisitor

UniqueVisitor

Method Detail

init

setStartIndex

setMaxFeatures

setPreserveOrder

getStartIndex

getMaxFeatures

getExpressions

getResultType

visit

visit

getExpression

getUnique

setValue

reset

getResult

hasLimits

isPreserveOrder