com.facebook.config.FileJSONProvider.java Source code

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Here is the source code for com.facebook.config.FileJSONProvider.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.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Pattern;

/**
 * Provides JSON stored in a file
 */
public class FileJSONProvider implements JSONProvider {
    private static final Pattern COMMENT_LINE = Pattern.compile("^\\s*//.*");

    private final File file;

    public FileJSONProvider(File file) {
        this.file = file;
    }

    protected BufferedReader getReader() throws FileNotFoundException {
        return new BufferedReader(new FileReader(file));
    }

    private JSONObject fileToJSON() throws IOException, JSONException {
        StringBuilder sb = new StringBuilder(1024);
        BufferedReader in = null;

        try {
            in = getReader();
            String line;

            while ((line = in.readLine()) != null) {
                // skip simple comment lines
                if (!COMMENT_LINE.matcher(line).find()) {
                    sb.append(line);
                }
            }

        } finally {
            if (in != null) {
                in.close();
            }
        }

        return new JSONObject(sb.toString());
    }

    @Override
    public JSONObject get() throws JSONException {
        try {
            return fileToJSON();
        } catch (IOException e) {
            throw new JSONException(e);
        }
    }
}