PropertiesFactory.java

/*
 * The MIT License
 *
 * Copyright 2015 Ahseya.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.github.horrorho.liquiddonkey.settings;

import com.github.horrorho.liquiddonkey.iofunction.IOSupplier;
import java.io.IOException;
import java.io.InputStream;
import java.util.Comparator;
import java.util.Properties;
import java.util.stream.Stream;
import net.jcip.annotations.Immutable;
import net.jcip.annotations.ThreadSafe;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * PropertiesFactory.
 *
 * @author Ahseya
 */
@Immutable
@ThreadSafe
public final class PropertiesFactory {

    private static final Logger logger = LoggerFactory.getLogger(PropertiesFactory.class);

    private static final PropertiesFactory instance = new PropertiesFactory();

    public static PropertiesFactory create() {
        return instance;
    }

    PropertiesFactory() {
    }

    public Properties fromDefaults() {
        Properties properties = new Properties();

        Stream.of(Property.values())
                .filter(property -> property.getDefaultValue() != null)
                .forEach(property -> properties.put(property.toString(), property.getDefaultValue()));

        return properties;
    }

    public Properties fromInputStream(IOSupplier<InputStream> supplier) throws IOException {
        return fromInputStream(new Properties(), supplier);
    }

    public Properties fromInputStream(Properties defaults, IOSupplier<InputStream> supplier) throws IOException {
        Properties properties = new Properties(defaults);
        try (InputStream inputStream = supplier.get()) {
            if (inputStream != null) {
                properties.load(inputStream);

                // Only tests the newly loaded properties for key validity, not the defaults.
                properties.entrySet().stream()
                        .sorted(Comparator.comparing(e -> e.getKey().toString()))
                        .forEach(entry -> {
                            String key = entry.getKey().toString();
                            String value = entry.getValue().toString();
                            
                            try {
                                Property property = Property.valueOf(key);
                                logger.trace("-- fromInputStream() > property: {} key: {}", property, value);

                            } catch (IllegalArgumentException ex) {
                                System.err.println("WARN: Invalid properties file key: " + key);
                                logger.warn("-- fromInputStream() > unknown property key: {}", key);
                            }
                        });
            } else {
                throw new IOException("Null input stream");
            }
        }
        return properties;
    }
}