Class DecayFunctionParser<DFB extends DecayFunctionBuilder<DFB>>

All Implemented Interfaces:

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 Details


      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