Package org.apache.lucene.util

Class AttributeImpl

java.lang.Object
org.apache.lucene.util.AttributeImpl
All Implemented Interfaces:
Cloneable, Attribute
Direct Known Subclasses:
BoostAttributeImpl, CharTermAttributeImpl, FlagsAttributeImpl, FuzzyTermsEnum.LevenshteinAutomataAttributeImpl, KeywordAttributeImpl, MaxNonCompetitiveBoostAttributeImpl, NumericTokenStream.NumericTermAttributeImpl, OffsetAttributeImpl, PayloadAttributeImpl, PositionIncrementAttributeImpl, PositionLengthAttributeImpl, 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.

  • 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.

    • 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

      public 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.

      The default implementation calls AttributeReflector.reflect(java.lang.Class<? extends org.apache.lucene.util.Attribute>, java.lang.String, java.lang.Object) for all non-static fields from the implementing class, using the field name as key and the field value as value. The Attribute class is also determined by reflection. Please note that the default implementation can only handle single-Attribute implementations.

      Custom 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:

    • 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()
      Shallow clone. Subclasses must override this if they need to clone any members deeply,