com.facebook.config.SystemPropOverridingJSONProvider.java Source code

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Here is the source code for com.facebook.config.SystemPropOverridingJSONProvider.java

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/*
 * Copyright (C) 2012 Facebook, Inc.
 *
 * 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 com.facebook.config;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.Map;

/**
 * Load system command-line properties to override JSON key-value pairs
 */
public class SystemPropOverridingJSONProvider implements JSONProvider {
    private final JSONProvider jsonProvider;

    public SystemPropOverridingJSONProvider(JSONProvider jsonProvider) {
        this.jsonProvider = jsonProvider;
    }

    private JSONObject includeSystemProperties(JSONObject jsonObject) throws JSONException {

        for (Map.Entry<Object, Object> entry : System.getProperties().entrySet()) {
            if (entry.getKey() instanceof String && entry.getValue() instanceof String) {
                String key = (String) entry.getKey();
                String value = (String) entry.getValue();
                // try first to see if value might be a json Object
                try {
                    JSONObject valueAsJSONObject = new JSONObject(value);

                    jsonObject.put(key, valueAsJSONObject);
                } catch (JSONException e) {
                    // means value is just a plain old string
                    jsonObject.put(key, value);
                }
            }
        }
        return jsonObject;
    }

    @Override
    public JSONObject get() throws JSONException {
        return includeSystemProperties(jsonProvider.get());
    }
}