com.sap.cds.adapter.odata.v4.query.apply.HierarchySubsetConverter Maven / Gradle / Ivy

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OData V4 adapter for CDS Services Java
There is a newer version: 3.6.0
/**************************************************************************
 * (C) 2019-2024 SAP SE or an SAP affiliate company. All rights reserved. *
 **************************************************************************/
package com.sap.cds.adapter.odata.v4.query.apply;

import java.util.List;

import org.apache.olingo.server.api.uri.queryoption.ApplyItem;
import org.apache.olingo.server.api.uri.queryoption.apply.Ancestors;
import org.apache.olingo.server.api.uri.queryoption.apply.Descendants;
import org.apache.olingo.server.api.uri.queryoption.apply.HierarchicalSubsetTransformation;

import com.sap.cds.adapter.odata.v4.query.ExpressionParser;
import com.sap.cds.ql.CQL;
import com.sap.cds.ql.cqn.CqnElementRef;
import com.sap.cds.ql.cqn.CqnStructuredTypeRef;
import com.sap.cds.ql.cqn.transformation.CqnAncestorsTransformation;
import com.sap.cds.ql.cqn.transformation.CqnTransformation;
import com.sap.cds.ql.impl.transformations.AncestorsTrafo;
import com.sap.cds.ql.impl.transformations.DescendantsTrafo;

public abstract class HierarchySubsetConverter {

	public static CqnAncestorsTransformation ancestors(Ancestors ancestors, ExpressionParser expressionParser) {
		ParamConverter converter = new ParamConverter(ancestors, expressionParser);
		return AncestorsTrafo
				.ancestors(converter.hierarchyReference(), converter.hierarchyQualifier(), converter.nodeProperty())
				.distanceFromStart(converter.distinctFromStart()).keepStart(converter.keepStart())
				.transformations(converter.transformations());
	}

	public static CqnTransformation descendants(Descendants descendants, ExpressionParser expressionParser) {
		ParamConverter converter = new ParamConverter(descendants, expressionParser);
		return DescendantsTrafo
				.descendants(converter.hierarchyReference(), converter.hierarchyQualifier(), converter.nodeProperty())
				.distanceFromStart(converter.distinctFromStart()).keepStart(converter.keepStart())
				.transformations(converter.transformations());
	}

	private static class ParamConverter {
		private ExpressionParser parser;
		private HierarchicalSubsetTransformation transformation;

		public ParamConverter(HierarchicalSubsetTransformation transformation, ExpressionParser expressionParser) {
			this.transformation = transformation;
			this.parser = expressionParser;
		}

		CqnStructuredTypeRef hierarchyReference() {
			return parser.getTargetTypeRef(transformation.getHierarchyReference());
		}

		String hierarchyQualifier() {
			return transformation.getHierarchyQualifier();
		}

		CqnElementRef nodeProperty() {
			return CQL.get(parser.toSegmentList(transformation.getNodeProperty()));
		}

		List transformations() {
			List applies = transformation.getTransformations();
			List transformations;
			ApplyHandler applyHandler = new ApplyHandler(applies, parser);
			transformations = applyHandler.getTransformations(0);
			return transformations;
		}

		int distinctFromStart() {
			return transformation.getDistanceFromStart() != null ? transformation.getDistanceFromStart() : -1;
		}

		boolean keepStart() {
			return transformation.isKeepStart() == Boolean.TRUE;// TODO check default
		}
	}

}