com.sap.cds.reflect.impl.CdsAnnotationReader Maven / Gradle / Ivy

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CDS4j Core
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/*******************************************************************
 * © 2020 SAP SE or an SAP affiliate company. All rights reserved. *
 *******************************************************************/
package com.sap.cds.reflect.impl;

import static com.sap.cds.reflect.impl.CdsAnnotatableImpl.CdsAnnotationImpl.annotation;

import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.google.common.hash.HashCode;
import com.google.common.hash.HashFunction;
import com.google.common.hash.Hashing;
import com.sap.cds.ql.cqn.CqnSyntaxException;
import com.sap.cds.reflect.CdsAnnotation;

public class CdsAnnotationReader {

	private static final ObjectMapper jackson = new ObjectMapper();
	private static final JavaType UNKNOWN_TYPE = TypeFactory.unknownType();
	private static final HashFunction HASHER = Hashing.goodFastHash(160);

	private CdsAnnotationReader() {
	}

	public static List> read(CdsModelReader.Config config, JsonNode jsonObject) {
		List> list = new ArrayList<>();
		Iterator> fields = jsonObject.fields();
		while (fields.hasNext()) {
			String name = fields.next().getKey();
			if (isAnnotation(name) && (config.includeUIAnnotations() || !name.startsWith("@UI."))) {
				JsonNode node = jsonObject.get(name);
				if (!node.isNull()) {
					list.add(getAnnotation(name, node));
				}
			}
		}

		return list;
	}

	private static CdsAnnotation getAnnotation(String name, JsonNode node) {
		String key = CdsAnnotatableImpl.removeAt(name) + ":" + node.toString();
		HashCode hash = HASHER.hashString(key, StandardCharsets.UTF_8);
		return CdsModelArtifactsCache.getInstance().getAnnotations().get(hash, h -> parseAnnotation(name, node));
	}

	private static CdsAnnotation parseAnnotation(String name, JsonNode node) {
		Object val;
		try {
			val = jackson.treeToValue(node, UNKNOWN_TYPE);
		} catch (JsonProcessingException e) {
			throw new CqnSyntaxException("Unparsable annotation: " + node.toString(), e);
		}
		return annotation(name, val);
	}

	public static boolean isAnnotation(String key) {
		return key.startsWith("@");
	}
}