com.sap.cds.ql.cqn.CqnAnalyzer Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of cds4j-api Show documentation
CDS4J API
There is a newer version: 3.6.1
/*******************************************************************
 * © 2020 SAP SE or an SAP affiliate company. All rights reserved. *
 *******************************************************************/
package com.sap.cds.ql.cqn;

import java.util.function.Supplier;

import com.google.common.annotations.Beta;
import com.sap.cds.Cds4jServiceLoader;
import com.sap.cds.ql.cqn.CqnReference.Segment;
import com.sap.cds.reflect.CdsModel;

/**
 * API to introspect {@link CqnStructuredTypeRef CqnStructuredTypeRef(s)} and
 * {@link CqnStatement CqnStatement(s)}
 */
public final class CqnAnalyzer {

	private static final CqnAnalyzerSPI analyzer = Cds4jServiceLoader.load(CqnAnalyzerSPI.class);

	private final Supplier modelSupplier;

	private CqnAnalyzer(Supplier modelSupplier) {
		this.modelSupplier = modelSupplier;
	}

	/**
	 * Returns true if the given CQN statement is a query with a single count item
	 * on the select list.
	 *
	 * @param cqn the CQN statement
	 * @return true if the given statement is a count query
	 */
	public static boolean isCountQuery(CqnStatement cqn) {
		return analyzer.isCountQuery(cqn);
	}

	/**
	 * Creates an instance of {@code CqnAnalyzer}.
	 *
	 * @param model the {@link CdsModel}
	 * @return the {@code CqnAnalyzer} instance
	 */
	public static CqnAnalyzer create(CdsModel model) {
		return create(() -> model);
	}

	/**
	 * Creates an instance of {@code CqnAnalyzer}.
	 *
	 * @param modelSupplier the {@link CdsModel} supplier
	 * @return the {@code CqnAnalyzer} instance
	 */
	public static CqnAnalyzer create(Supplier modelSupplier) {
		return new CqnAnalyzer(modelSupplier);
	}

	/**
	 * Analyzes the {@link Segment Segment(s)} of the given
	 * {@link CqnStructuredTypeRef}.
	 *
	 * @param ref the {@code CqnStructuredTypeRef} to be analyzed
	 * @return the {@link AnalysisResult} with information on the segments of the
	 *         {@code CqnStructuredTypeRef}
	 */
	public AnalysisResult analyze(CqnStructuredTypeRef ref) {
		return analyzer.analyze(modelSupplier.get(), ref);
	}

	/**
	 * Analyzes the {@code ref} and {@code where} condition of the given
	 * {@link CqnFilterableStatement}.
	 *
	 * @param statement the {@link CqnFilterableStatement} statement to be analyzed
	 *                  ({@link CqnDelete}, {@link CqnUpdate}, or {@link CqnSelect})
	 * @return the {@link AnalysisResult} with information on the {@code ref}
	 *         {@link Segment Segment(s)} and {@code where} condition of the filterable statement
	 */
	public AnalysisResult analyze(CqnFilterableStatement statement) {
		return analyzer.analyze(modelSupplier.get(), statement);
	}

	@Beta
	public Iterable resolveRefItems(CqnSelect query) {
		return analyzer.resolveRefItems(modelSupplier.get(), query);
	}

	/**
	 * Service Provider Interface for the {@link CqnAnalyzer}.
	 */
	public interface CqnAnalyzerSPI {

		AnalysisResult analyze(CdsModel model, CqnStructuredTypeRef ref);

		AnalysisResult analyze(CdsModel model, CqnFilterableStatement stmt);

		Iterable resolveRefItems(CdsModel model, CqnSelect query);

		boolean isCountQuery(CqnStatement cqn);
	}

}