Package org.elasticsearch.index.query.functionscore

Class DecayFunctionParser<DFB extends DecayFunctionBuilder<DFB>>

java.lang.Object

org.elasticsearch.index.query.functionscore.DecayFunctionParser<DFB>

All Implemented Interfaces:

ScoreFunctionParser<DFB>

public final class DecayFunctionParser<DFB extends DecayFunctionBuilder<DFB>>
extends Object
implements ScoreFunctionParser<DFB>

Parser used for all decay functions, one instance each. It parses this kind of input:

 
 {
      "fieldname1" : {
          "origin" = "someValue",
          "scale" = "someValue"
      },
      "multi_value_mode" : "min"
 }
 
 

"origin" here refers to the reference point and "scale" to the level of uncertainty you have in your origin.

For example, you might want to retrieve an event that took place around the 20 May 2010 somewhere near Berlin. You are mainly interested in events that are close to the 20 May 2010 but you are unsure about your guess, maybe it was a week before or after that. Your "origin" for the date field would be "20 May 2010" and your "scale" would be "7d".

This class parses the input and creates a scoring function from the parameters origin and scale.

To write a new decay scoring function, create a new class that extends DecayFunctionBuilder, setup a PARSER field with this class, and register them in SearchModule.registerScoreFunctions(java.util.List<org.elasticsearch.plugins.SearchPlugin>) or SearchPlugin.getScoreFunctions() See GaussDecayFunctionBuilder.PARSER for an example.

Field Summary

Fields

Modifier and Type	Field	Description
static org.elasticsearch.common.xcontent.ParseField	MULTI_VALUE_MODE

Constructor Summary

Constructors

Constructor	Description
DecayFunctionParser(BiFunction<String,BytesReference,DFB> createFromBytes)	Create the parser using a method reference to a "create from bytes" constructor for the DecayFunctionBuilder.

Method Summary

Modifier and Type	Method	Description
DFB	fromXContent(org.elasticsearch.common.xcontent.XContentParser parser)	Parses bodies of the kind

Methods inherited from class java.lang.Object

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

Field Details

MULTI_VALUE_MODE

public static final org.elasticsearch.common.xcontent.ParseField MULTI_VALUE_MODE

Constructor Details

DecayFunctionParser

public DecayFunctionParser(BiFunction<String,BytesReference,DFB> createFromBytes)

Create the parser using a method reference to a "create from bytes" constructor for the DecayFunctionBuilder. We use a method reference here so each use of this class doesn't have to subclass it.

Method Details

fromXContent

public DFB fromXContent(org.elasticsearch.common.xcontent.XContentParser parser)
                 throws IOException,
ParsingException

Parses bodies of the kind

 
 {
      "fieldname1" : {
          "origin" : "someValue",
          "scale" : "someValue"
      },
      "multi_value_mode" : "min"
 }
 
 

Specified by:

fromXContent in interface ScoreFunctionParser<DFB extends DecayFunctionBuilder<DFB>>

Throws:

IOException

ParsingException