com.parse.ParseCurrentConfigController.java Source code

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Here is the source code for com.parse.ParseCurrentConfigController.java

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/*
 * Copyright (c) 2015-present, Parse, LLC.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
package com.parse;

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

import java.io.File;
import java.io.IOException;
import java.util.concurrent.Callable;

import bolts.Task;

/** package */
class ParseCurrentConfigController {

    private final Object currentConfigMutex = new Object();
    /* package for test */ ParseConfig currentConfig;
    private File currentConfigFile;

    public ParseCurrentConfigController(File currentConfigFile) {
        this.currentConfigFile = currentConfigFile;
    }

    public Task<Void> setCurrentConfigAsync(final ParseConfig config) {
        return Task.call(new Callable<Void>() {
            @Override
            public Void call() throws Exception {
                synchronized (currentConfigMutex) {
                    currentConfig = config;
                    saveToDisk(config);
                }
                return null;
            }
        }, ParseExecutors.io());
    }

    public Task<ParseConfig> getCurrentConfigAsync() {
        return Task.call(new Callable<ParseConfig>() {
            @Override
            public ParseConfig call() throws Exception {
                synchronized (currentConfigMutex) {
                    if (currentConfig == null) {
                        ParseConfig config = getFromDisk();
                        currentConfig = (config != null) ? config : new ParseConfig();
                    }
                }
                return currentConfig;
            }
        }, ParseExecutors.io());
    }

    /**
     * Retrieves a {@code ParseConfig} from a file on disk.
     *
     * @return The {@code ParseConfig} that was retrieved. If the file wasn't found, or the contents
     *          of the file is an invalid {@code ParseConfig}, returns null.
     */
    /* package for test */ ParseConfig getFromDisk() {
        JSONObject json;
        try {
            json = ParseFileUtils.readFileToJSONObject(currentConfigFile);
        } catch (IOException | JSONException e) {
            return null;
        }
        return ParseConfig.decode(json, ParseDecoder.get());
    }

    /* package */ void clearCurrentConfigForTesting() {
        synchronized (currentConfigMutex) {
            currentConfig = null;
        }
    }

    /**
     * Saves the {@code ParseConfig} to the a file on disk as JSON.
     *
     * @param config
     *          The ParseConfig which needs to be saved.
     */
    /* package for test */ void saveToDisk(ParseConfig config) {
        JSONObject object = new JSONObject();
        try {
            JSONObject jsonParams = (JSONObject) NoObjectsEncoder.get().encode(config.getParams());
            object.put("params", jsonParams);
        } catch (JSONException e) {
            throw new RuntimeException("could not serialize config to JSON");
        }
        try {
            ParseFileUtils.writeJSONObjectToFile(currentConfigFile, object);
        } catch (IOException e) {
            //TODO (grantland): We should do something if this fails...
        }
    }
}