@Override
    protected DocprocChain buildChain(DeployState deployState, TreeConfigProducer<AnyConfigProducer> ancestor, Element producerSpec,
                                      ChainSpecification specWithoutInnerComponents) {
        Map<Pair<String, String>, String> fieldNameSchemaMap = DocumentProcessorModelBuilder.parseFieldNameSchemaMap(producerSpec);
        return new DocprocChain(specWithoutInnerComponents, fieldNameSchemaMap);
    }
Builds a docproc chain from xml

@author gjoranv
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/chains/docproc/DomDocprocChainBuilder.java