Configuration.java

/*
 * Copyright 2011 Tyler Blair. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and contributors and should not be interpreted as representing official policies,
 * either expressed or implied, of anybody else.
 */

package com.griefcraft.util.config;

import com.griefcraft.lwc.LWC;
import com.griefcraft.scripting.ModuleLoader;
import com.griefcraft.util.Updater;
import org.yaml.snakeyaml.DumperOptions;
import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.constructor.SafeConstructor;
import org.yaml.snakeyaml.reader.UnicodeReader;
import org.yaml.snakeyaml.representer.Representer;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.HashMap;
import java.util.Map;

public class Configuration extends ConfigurationNode {
    private Yaml yaml;
    private File file;

    /**
     * List of loaded config files
     */
    private static Map<String, Configuration> loaded = new HashMap<String, Configuration>();

    private Configuration(File file) {
        super(new HashMap<String, Object>());

        DumperOptions options = new DumperOptions();
        options.setIndent(4);
        options.setDefaultFlowStyle(DumperOptions.FlowStyle.BLOCK);

        yaml = new Yaml(new SafeConstructor(), new Representer(), options);

        this.file = file;
    }

    /**
     * Reload the configuration maps
     */
    public static void reload() {
        for (Configuration configuration : loaded.values()) {
            configuration.load();
        }
    }

    /**
     * @return the list of loaded config files
     */
    public static Map<String, Configuration> getLoaded() {
        return loaded;
    }

    /**
     * Create and load a configuration file
     *
     * @param config
     * @return
     */
    public static Configuration load(String config) {
        if (loaded.containsKey(config)) {
            return loaded.get(config);
        }

        File file = new File(ModuleLoader.ROOT_PATH + config);

        // if it does not exist, attempt to download it if possible :-)
        if (!file.exists()) {
            Updater updater = LWC.getInstance().getPlugin().getUpdater();
            updater.downloadConfig(config);
        }

        Configuration configuration = new Configuration(file);
        configuration.load();
        loaded.put(config, configuration);

        return configuration;
    }

    /**
     * Loads the configuration file. All errors are thrown away.
     */
    void load() {
        FileInputStream stream = null;

        try {
            stream = new FileInputStream(file);
            read(yaml.load(new UnicodeReader(stream)));
        } catch (IOException e) {
            root = new HashMap<String, Object>();
        } catch (ConfigurationException e) {
            root = new HashMap<String, Object>();
        } finally {
            try {
                if (stream != null) {
                    stream.close();
                }
            } catch (IOException e) {
            }
        }
    }

    /**
     * Saves the configuration to disk. All errors are clobbered.
     *
     * @return true if it was successful
     */
    public boolean save() {
        FileOutputStream stream = null;

        File parent = file.getParentFile();
        if (parent != null) {
            parent.mkdirs();
        }

        try {
            stream = new FileOutputStream(file);
            yaml.dump(root, new OutputStreamWriter(stream, "UTF-8"));
            return true;
        } catch (IOException e) {
        } finally {
            try {
                if (stream != null) {
                    stream.close();
                }
            } catch (IOException e) {
            }
        }

        return false;
    }

    @SuppressWarnings("unchecked")
    private void read(Object input) throws ConfigurationException {
        try {
            if (null == input) {
                root = new HashMap<String, Object>();
            } else {
                root = (Map<String, Object>) input;
            }
        } catch (ClassCastException e) {
            throw new ConfigurationException("Root document must be an key-value structure");
        }
    }

    /**
     * This method returns an empty ConfigurationNode for using as a
     * default in methods that select a node from a node list.
     *
     * @return
     */
    public static ConfigurationNode getEmptyNode() {
        return new ConfigurationNode(new HashMap<String, Object>());
    }
}