org.cfg4j.source.context.propertiesprovider.JsonBasedPropertiesProvider.java Source code

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Here is the source code for org.cfg4j.source.context.propertiesprovider.JsonBasedPropertiesProvider.java

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/*
 * Copyright 2015-2016 Norbert Potocki (norbert.potocki@nort.pl)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.cfg4j.source.context.propertiesprovider;

import static java.util.Objects.requireNonNull;

import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONTokener;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;

/**
 * {@link PropertiesProvider} that interprets given stream as JSON file.
 */
public class JsonBasedPropertiesProvider extends FormatBasedPropertiesProvider {

    /**
     * Get {@link Properties} for a given {@code inputStream} treating it as a JSON file.
     *
     * @param inputStream input stream representing JSON file
     * @return properties representing values from {@code inputStream}
     * @throws IllegalStateException when unable to read properties
     */
    @Override
    public Properties getProperties(InputStream inputStream) {
        requireNonNull(inputStream);

        Properties properties = new Properties();

        try {

            JSONTokener tokener = new JSONTokener(inputStream);
            if (tokener.end()) {
                return properties;
            }
            if (tokener.nextClean() == '"') {
                tokener.back();
                properties.put("content", tokener.nextValue().toString());
            } else {
                tokener.back();
                JSONObject obj = new JSONObject(tokener);

                Map<String, Object> yamlAsMap = convertToMap(obj);
                properties.putAll(flatten(yamlAsMap));
            }

            return properties;

        } catch (Exception e) {
            throw new IllegalStateException("Unable to load json configuration from provided stream", e);
        }
    }

    /**
     * Convert given Json document to a multi-level map.
     */
    @SuppressWarnings("unchecked")
    private Map<String, Object> convertToMap(Object jsonDocument) {
        Map<String, Object> jsonMap = new LinkedHashMap<>();

        // Document is a text block
        if (!(jsonDocument instanceof JSONObject)) {
            jsonMap.put("content", jsonDocument);
            return jsonMap;
        }

        JSONObject obj = (JSONObject) jsonDocument;
        for (String key : obj.keySet()) {
            Object value = obj.get(key);

            if (value instanceof JSONObject) {
                value = convertToMap(value);
            } else if (value instanceof JSONArray) {
                ArrayList<Map<String, Object>> collection = new ArrayList<>();

                for (Object element : ((JSONArray) value)) {
                    collection.add(convertToMap(element));
                }

                value = collection;
            }

            jsonMap.put(key, value);
        }
        return jsonMap;

    }
}