Parametric Mappings

When the query parameter is set, the mapping template executes in parametric mode: a SPARQL query is run against the data, and the template is executed once per result row, producing multiple outputs.

This is useful when you need to generate one output file per entity (e.g., one CSV per agency, one XML per record).

How It Works

1. The SPARQL query in query is executed against the reader.
2. For each result row, the bindings are made available as variables in the template.
3. The template is executed once per row.

Output Behavior

filename set?	Exchange Body
Yes	List<Path> — one file per result row. File names are derived from the query bindings appended to the base filename.
No	Map<String, String> — key per result row → template output string.

Parameters

All Mapping Template parameters apply. The key additional parameter is:

Parameter	Type	Required	Default	Description
query	ChimeraResourceBean	Yes	—	Resource pointing to the SPARQL query file. Each result row triggers one template execution. See ChimeraResource.

Example

Generate one CSV file per agency from an RDF graph:

Java DSLYAML

ChimeraResourceBean triples = new ChimeraResourceBean(
    "file://./data/input.ttl", "turtle");
ChimeraResourceBean template = new ChimeraResourceBean(
    "file://./data/template.vm", "");
ChimeraResourceBean query = new ChimeraResourceBean(
    "file://./data/query.txt", "");
getCamelContext().getRegistry().bind("triples", triples);
getCamelContext().getRegistry().bind("template", template);
getCamelContext().getRegistry().bind("query", query);

from("graph://get")
    .to("graph://add?chimeraResource=#bean:triples")
    .to("mapt://rdf?template=#bean:template&query=#bean:query&basePath=./output&filename=agency.csv");

- beans:
    - name: triples
      type: com.cefriel.util.ChimeraResourceBean
      properties:
        url: "file://./data/input.ttl"
        serializationFormat: "turtle"
    - name: template
      type: com.cefriel.util.ChimeraResourceBean
      properties:
        url: "file://./data/template.vm"
        serializationFormat: ""
    - name: query
      type: com.cefriel.util.ChimeraResourceBean
      properties:
        url: "file://./data/query.txt"
        serializationFormat: ""

- route:
    from:
      uri: "graph://get"
    steps:
      - to:
          uri: "graph://add"
          parameters:
            chimeraResource: "#triples"
      - to:
          uri: "mapt://rdf"
          parameters:
            template: "#template"
            query: "#query"
            basePath: "./output"
            filename: "agency.csv"

If the query returns two rows (e.g., for agencies "BEST-AGENCY" and "WOW-AGENCY"), two files are created: agency-BEST-AGENCY.csv and agency-WOW-AGENCY.csv. The exchange body will contain a List<Path> pointing to both files.