es.deusto.weblab.client.configuration.ConfigurationManager.java Source code

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Here is the source code for es.deusto.weblab.client.configuration.ConfigurationManager.java

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/*
* Copyright (C) 2005 onwards University of Deusto
* All rights reserved.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution.
*
* This software consists of contributions made by many individuals, 
* listed below:
*
* Author: Pablo Ordua <pablo@ordunya.com>
*
*/
package es.deusto.weblab.client.configuration;

import java.util.HashMap;
import java.util.Map;

import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.json.client.JSONArray;
import com.google.gwt.json.client.JSONObject;
import com.google.gwt.json.client.JSONParser;
import com.google.gwt.json.client.JSONValue;

import es.deusto.weblab.client.configuration.exceptions.InvalidConfigurationValueException;
import es.deusto.weblab.client.configuration.exceptions.ConfigurationException;

public class ConfigurationManager extends ConfigurationRetriever implements IConfigurationManager {

    private final String configurationPath;
    private final IConfigurationLoadedCallback callback;

    public ConfigurationManager(String path, IConfigurationLoadedCallback callback) {
        this.configurationPath = path;
        this.callback = callback;
    }

    public void start() {
        final RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, this.configurationPath);
        try {
            builder.sendRequest(null, new RequestCallback() {
                @Override
                public void onError(Request request, Throwable exception) {
                    ConfigurationManager.this.callback.onFailure(exception);
                }

                @Override
                public void onResponseReceived(Request request, Response response) {
                    if (response.getStatusCode() / 100 == 2 || response.getStatusCode() / 100 == 3) {
                        final JSONValue value;
                        try {
                            value = JSONParser.parseLenient(response.getText());
                        } catch (final Exception e) {
                            ConfigurationManager.this.callback.onFailure(new ConfigurationException(
                                    "Error parsing configuration: " + e.getMessage(), e));
                            return;
                        }

                        final JSONObject objValue = value.isObject();
                        if (objValue == null) {
                            ConfigurationManager.this.callback.onFailure(
                                    new ConfigurationException("Error parsing configuration: object expected"));
                            return;
                        }

                        for (final String key : objValue.keySet()) {
                            final JSONValue currentValue = objValue.get(key);
                            if (currentValue == null) {
                                ConfigurationManager.this.callback.onFailure(new ConfigurationException(
                                        "Error parsing configuration: empty value for key: " + key));
                                return;
                            }
                            ConfigurationManager.this.configurationMap.put(key, currentValue);
                        }

                        ConfigurationManager.this.callback.onLoaded();
                    } else {
                        ConfigurationManager.this.callback
                                .onFailure(new ConfigurationException("Invalid status code: "
                                        + response.getStatusCode() + "; " + response.getStatusText()));
                    }
                }
            });
        } catch (final RequestException e1) {
            ConfigurationManager.this.callback
                    .onFailure(new ConfigurationException("Exception thrown creating request: " + e1.getMessage()));
        }
    }

    @Override
    public IConfigurationRetriever[] getExperimentsConfiguration(String experimentType)
            throws InvalidConfigurationValueException {
        final JSONValue value = this.configurationMap.get("experiments");
        if (value == null) // If no experiment is configured, just return an empty array
            return new IConfigurationRetriever[] {};

        final JSONObject objectValue = value.isObject();
        if (objectValue == null)
            throw new InvalidConfigurationValueException(
                    "'experiments' field in the configuration file must be an object!!!");

        final JSONValue experimentTypeValue = objectValue.get(experimentType);
        if (experimentTypeValue == null) // If no experiment of that type is configured, just return an empty array
            return new IConfigurationRetriever[] {};

        final JSONArray experimentTypeArray = experimentTypeValue.isArray();
        if (experimentTypeArray == null)
            throw new InvalidConfigurationValueException(
                    "Any experiment type in the 'experiments' field of the configuration file must be an array!");

        final IConfigurationRetriever[] resultingConfigurationRetrievers = new IConfigurationRetriever[experimentTypeArray
                .size()];
        for (int i = 0; i < experimentTypeArray.size(); ++i) {
            final JSONValue currentExperimentConfiguration = experimentTypeArray.get(i);
            final JSONObject currentExperimentConfigurationObject = currentExperimentConfiguration.isObject();
            if (currentExperimentConfigurationObject == null)
                throw new InvalidConfigurationValueException(
                        "Any experiment in the array of experiment types of 'experiments' in the configuration file must be an object!");

            final Map<String, JSONValue> experimentConfiguration = new HashMap<String, JSONValue>();
            for (final String key : currentExperimentConfigurationObject.keySet())
                experimentConfiguration.put(key, currentExperimentConfigurationObject.get(key));

            resultingConfigurationRetrievers[i] = new ConfigurationRetriever(experimentConfiguration, this);
        }

        return resultingConfigurationRetrievers;
    }
}