HierarchyTransformer

Adds hierarchical tags to documents using a delimiter for structured categorization.

importerJavadoc: HierarchyTransformer

Notes

Given a separator, split a field string into multiple segments representing each node of a hierarchical branch. This is useful when faceting, to find out how many documents fall under each node of a hierarchy. For example, take this hierarchical string:

/vegetable/potato/sweet

We specify a slash (/) separator and it will produce the following entries in the specified document metadata field:

/vegetable

/vegetable/potato
 /vegetable/potato/sweet

If no target field is specified toField the source field fromField will be used to store the resulting values. The same applies to the source and target hierarchy separators (fromSeparator and toSeparator).

You can keepEmptySegments, as well as specify whether the fromSeparator is a regular expression. When using regular expression without a "toSeparator", the text matching the expression is kept as is and thus can be different for each segment.

Storing values in an existing field

If a target field with the same name already exists for a document, values will be added to the end of the existing value list. It is possible to change this default behavior by supplying a PropertySetter.

Can be used both as a pre-parse or post-parse handler.

Examples

The example will expand a slash-separated vegetable hierarchy found in a "vegetable" field into a "vegetableHierarchy" field.

YAML

handler:
  class: HierarchyTransformer
  operations:
    - fromField: vegetable
      toField: vegetableHierarchy
      fromSeparator: /

JSON

{
  "handler": {
    "class": "HierarchyTransformer",
    "operations": [
      {
        "fromField": "vegetable",
        "toField": "vegetableHierarchy",
        "fromSeparator": "/"
      }
    ]
  }
}

XML

<handler>
  <class>HierarchyTransformer</class>
  <operations>
    <fromField>vegetable</fromField>
    <toField>vegetableHierarchy</toField>
    <fromSeparator>/</fromSeparator>
  </operations>
</handler>

Usage

Full configuration skeleton, with every option and its default

YAML

class: HierarchyTransformer
label: string
operations:
  - fromField: string
    fromSeparator: string
    keepEmptySegments: false
    onSet: APPEND
    regex: false
    toField: string
    toSeparator: string

JSON

{
  "class": "HierarchyTransformer",
  "label": "string",
  "operations": [
    {
      "fromField": "string",
      "fromSeparator": "string",
      "keepEmptySegments": false,
      "onSet": "APPEND",
      "regex": false,
      "toField": "string",
      "toSeparator": "string"
    }
  ]
}

XML

<handler>
  <class>HierarchyTransformer</class>
  <label>string</label>
  <operations>
    <op>
      <fromField>string</fromField>
      <fromSeparator>string</fromSeparator>
      <keepEmptySegments>false</keepEmptySegments>
      <onSet>APPEND</onSet>
      <regex>false</regex>
      <toField>string</toField>
      <toSeparator>string</toSeparator>
    </op>
  </operations>
</handler>

Properties

Property	Type	Required	Default
label	string	No	-
operations	HierarchyOperation[]	No	-

Property Details

label

An optional, user-supplied label for this step in the importer pipeline. It has no effect on processing — it exists purely to help identify this step, for example in large configurations or in the visual configurator.

operations

this work