PropertyBinder to create additional Lucene field

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3

Yes that’s one solution.

If you want to use only one annotation, you can do this instead:

// NOTE: this is a binder, not a bridge.
class ImportanceBinder implements PropertyBinder {

	@Override
	public void bind(PropertyBindingContext context) {

		// This bridge is applied to properties of enum type, and that type is immutable.
		// Thus we don't need to declare precise dependencies.
		context.dependencies().useRootOnly();

		context.bridge(Importance.class, new ImportancePropertyBridge(
			context.indexSchemaElement()
					.field(context.bridgedElement().name(), f -> f.asString())
					.toReference(),
			context.indexSchemaElement()
					.field(context.bridgedElement().name() + "_numeric", f -> f.asInteger()
							.searchable(Searchable.NO).sortable(Sortable.YES))
					.toReference()
		));
	}

	private static class ImportancePropertyBridge
			implements PropertyBridge<Importance> {

		private final IndexFieldReference<String> stringField;
		private final IndexFieldReference<Integer> integerField;

		private ImportancePropertyBridge(
			IndexFieldReference<String> stringField,
			IndexFieldReference<Integer> integerField
		) {
			this.stringField = stringField;
			this.integerField = integerField;
		}

		@Override
		public void write(
			DocumentElement target, Importance bridgedElement,
			PropertyBridgeWriteContext context
		) {
			target.addValue( stringField, bridgedElement.name() );
			target.addValue( integerField, bridgedElement.getScore() );
		}
    }

}

@Entity @Indexed 
class Article {

	 // ...

	@PropertyBinding(binder = @PropertyBinderRef(type = ImportanceBinder.class))
	@Enumerated(EnumType.STRING)
	private Importance importance = Importance.NORMAL;

	 // ...

}

See also PropertyBinder, Declaring fields, Declaring field types.

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