com.sap.cds.adapter.rest.utils.Json Maven / Gradle / Ivy

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/**************************************************************************
 * (C) 2019-2021 SAP SE or an SAP affiliate company. All rights reserved. *
 **************************************************************************/
package com.sap.cds.adapter.rest.utils;

import java.io.Reader;
import java.util.Map;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * Helper class for JSON mappings that hides the concrete JSON open source library.
 */
public class Json {

    private final static ObjectMapper mapper = new ObjectMapper();
    
    private JsonNode json;
    
    private Json(JsonNode jsonNode) {
        this.json = jsonNode;
    }

    public static Json fromReader(Reader reader) throws JsonException {
        try {
            return new Json( mapper.readTree(reader) );
        } catch (Exception e) { //NOSONAR
            throw new JsonException("Failed to parse JSON data from Reader", e);
        }
    }
    
    public static Json fromString(String jsonData) throws JsonException {
        try {
            return new Json( mapper.readTree(jsonData) );
        } catch (Exception e) { //NOSONAR
            throw new JsonException("Failed to parse JSON data from '" + jsonData + "'", e);
        }
    }
    
    public static Json fromMap(Map entry) {
        return new Json(mapper.valueToTree(entry));
    }
    
    @SuppressWarnings("unchecked")
    public Map asMap() throws JsonException {
        if (json.isArray()) {
            throw new IllegalStateException("JSON is not an JSON object");
        }
        try {
            return mapper.treeToValue(this.json, Map.class);
        } catch (JsonProcessingException e) {
            throw new JsonException("Failed to convert JSON to map", e);
        }
    }
    
    public String asString() {
        return json.toString();
    }
}