org.n52.car.io.Preferences.java Source code

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Here is the source code for org.n52.car.io.Preferences.java

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/**
 * Copyright (C) 2013
 * by 52 North Initiative for Geospatial Open Source Software GmbH
 *
 * Contact: Andreas Wytzisk
 * 52 North Initiative for Geospatial Open Source Software GmbH
 * Martin-Luther-King-Weg 24
 * 48155 Muenster, Germany
 * info@52north.org
 *
 * 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 org.n52.car.io;

import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ServiceLoader;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.XMLConfiguration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Preferences {

    private static Preferences instance;
    private Configuration config;
    private URL server;
    private Access access;
    private static final String defaultFile = "/car.io-java-config.xml";
    private static final Logger logger = LoggerFactory.getLogger(Preferences.class);

    public enum Strings {
        CAR_IO_SERVER
    }

    public enum Booleans {
        VALIDATE_JSON
    }

    /**
     * returns the instance. if it is not available,
     * a new instance is created using the {@link #defaultFile}.
     * 
     * @return the instance
     */
    public static synchronized Preferences getInstance() {
        if (instance == null)
            initialize(Preferences.class.getResourceAsStream(defaultFile));

        return instance;
    }

    /**
     * @param config a serialized instance of {@link XMLConfiguration} represented
     * as an {@link InputStream}
     */
    public static synchronized void initialize(InputStream config) {
        instance = new Preferences(config);
    }

    private Preferences(InputStream stream) {
        XMLConfiguration xml = new XMLConfiguration();

        try {
            xml.load(stream);
        } catch (ConfigurationException e) {
            logger.warn(e.getMessage(), e);
        }

        this.config = xml;

        initCommonParameters();
    }

    private void initCommonParameters() {
        try {
            this.server = new URL(getProperty(Strings.CAR_IO_SERVER.toString()));
            this.access = instantiateAccess();
        } catch (MalformedURLException e) {
            logger.warn(e.getMessage(), e);
        }
    }

    private Access instantiateAccess() {
        ServiceLoader<Access> loader = ServiceLoader.load(Access.class);
        for (Access access : loader) {
            access.initialize(instantiateConnection());
            return access;
        }
        return null;
    }

    private Connection instantiateConnection() {
        ServiceLoader<Connection> loader = ServiceLoader.load(Connection.class);
        for (Connection connection : loader) {
            connection.initialize(getServer());
            return connection;
        }
        return null;
    }

    public String getProperty(String key) {
        return this.config.getString(key);
    }

    public int getInteger(String key) {
        return this.config.getInt(key);
    }

    public boolean getBoolean(String key) {
        return this.config.getBoolean(key);
    }

    public double getDouble(String key) {
        return this.config.getDouble(key);
    }

    public URL getServer() {
        return this.server;
    }

    public Access getAccess() {
        return access;
    }

    public void setAccess(Access ac) {
        this.access = ac;
    }

}