Package org.apache.lucene.util

# Class AttributeImpl

java.lang.Object
org.apache.lucene.util.AttributeImpl

All Implemented Interfaces:
  `Cloneable`, `Attribute`

Direct Known Subclasses:
  `BoostAttributeImpl`, `BytesTermAttributeImpl`, `CharTermAttributeImpl`, `FlagsAttributeImpl`, `KeywordAttributeImpl`, `MaxNonCompetitiveBoostAttributeImpl`, `OffsetAttributeImpl`, `PayloadAttributeImpl`, `PositionIncrementAttributeImpl`, `PositionLengthAttributeImpl`, `SentenceAttributeImpl`, `TermFrequencyAttributeImpl`, `TypeAttributeImpl`

public abstract class AttributeImpl extends Object implements Cloneable, Attribute
Base class for Attributes that can be added to a `AttributeSource`.

Attributes are used to add data in a dynamic, yet type-safe way to a source of usually streamed objects, e. g. a `TokenStream`.

All implementations must list all implemented `Attribute` interfaces in their `implements` clause. `AttributeSource` reflectively identifies all attributes and makes them available to consumers like `TokenStream`s.

## Constructor Summary

Constructors
Constructor
Description
`AttributeImpl()`

## Method Summary

Modifier and Type
Method
Description
`abstract void`
`clear()`
Clears the values in this AttributeImpl and resets it to its default value.
`AttributeImpl`
`clone()`
In most cases the clone is, and should be, deep in order to be able to properly capture the state of all attributes.
`abstract void`
`copyTo(AttributeImpl target)`
Copies the values from this Attribute into the passed-in target attribute.
`void`
`end()`
Clears the values in this AttributeImpl and resets it to its value at the end of the field.
`final String`
`reflectAsString(boolean prependAttClass)`
This method returns the current attribute values as a string in the following format by calling the `reflectWith(AttributeReflector)` method: iff `prependAttClass=true`: `"AttributeClass#key=value,AttributeClass#key=value"` iff `prependAttClass=false`: `"key=value,key=value"`
`abstract void`
`reflectWith(AttributeReflector reflector)`
This method is for introspection of attributes, it should simply add the key/values this attribute holds to the given `AttributeReflector`.

### Methods inherited from class java.lang.Object

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

## Constructor Details

### AttributeImpl

public AttributeImpl()

## Method Details

### clear

public abstract void clear()
Clears the values in this AttributeImpl and resets it to its default value. If this implementation implements more than one Attribute interface it clears all.

### end

public void end()
Clears the values in this AttributeImpl and resets it to its value at the end of the field. If this implementation implements more than one Attribute interface it clears all.

The default implementation simply calls `clear()`

### reflectAsString

public final String reflectAsString(boolean prependAttClass)
This method returns the current attribute values as a string in the following format by calling the `reflectWith(AttributeReflector)` method:

- iff `prependAttClass=true`: `"AttributeClass#key=value,AttributeClass#key=value"`
- iff `prependAttClass=false`: `"key=value,key=value"`

See Also:
  - `reflectWith(AttributeReflector)`

### reflectWith

public abstract void reflectWith(AttributeReflector reflector)
This method is for introspection of attributes, it should simply add the key/values this attribute holds to the given `AttributeReflector`.

Implementations look like this (e.g. for a combined attribute implementation):

       public void reflectWith(AttributeReflector reflector) {
         reflector.reflect(CharTermAttribute.class, "term", term());
         reflector.reflect(PositionIncrementAttribute.class, "positionIncrement", getPositionIncrement());
       }

If you implement this method, make sure that for each invocation, the same set of `Attribute` interfaces and keys are passed to `AttributeReflector.reflect(java.lang.Class<? extends org.apache.lucene.util.Attribute>, java.lang.String, java.lang.Object)` in the same order, but possibly different values. So don't automatically exclude e.g. `null` properties!

See Also:
  - `reflectAsString(boolean)`

### copyTo

public abstract void copyTo(AttributeImpl target)
Copies the values from this Attribute into the passed-in target attribute. The target implementation must support all the Attributes this implementation supports.

### clone

public AttributeImpl clone()
In most cases the clone is, and should be, deep in order to be able to properly capture the state of all attributes.

Overrides:
  `clone` in class `Object`