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Get rid of the boilerplate code in Java properties based configuration.

There is a newer version: 1.0.12

/*
 * Copyright (c) 2012-2015, Luigi R. Viggiano
 * All rights reserved.
 *
 * This software is distributable under the BSD license.
 * See the terms of the BSD license in the documentation provided with this software.
 */

package org.aeonbits.owner.util;

import java.io.Serializable;
import java.util.AbstractMap;
import java.util.AbstractMap.SimpleEntry;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import static java.util.Arrays.asList;

/**
 * Utility class to create a maps, lists and sets
 *  Examples of usage: 
 *  * import static org.aeonbits.owner.util.Collections.map;
 * import static org.aeonbits.owner.util.Collections.entry;
 * import static org.aeonbits.owner.util.Collections.set;
 * import static org.aeonbits.owner.util.Collections.list;
 *
 * Map<String, String> myMap = map("foo", "bar");
 * Map<String, String> myMap2 = map(entry("foo", "bar"), entry("baz", "qux");
 * Set<String> mySet = set("foo", "bar", "baz", "qux");
 * List<String> myList = list("foo", "bar", "baz", "qux");
 * 
 *
 * @author Luigi R. Viggiano
 * @since 1.0.6
 */
public abstract class Collections {

    // Suppresses default constructor, ensuring non-instantiability.
    private Collections() {}

    private static final class EntryMap extends AbstractMap implements Serializable {
        private static final long serialVersionUID = -789853606407653214L;
        private final Set> entries;

        private EntryMap(Entry... entries) {
            this.entries = set(entries);
        }

        @SuppressWarnings("unchecked")
        @Override
        public Set> entrySet() {
            return (Set) entries;
        }
    }

    public static  Entry entry(K key, V value) {
        return new SimpleEntry(key, value);
    }

    @SuppressWarnings("unchecked")
    public static  Map map(K key, V value) {
        return map(entry(key, value));
    }

    public static  Map map(Map.Entry... entries) {
        return new EntryMap(entries);
    }

    public static  Set set(E... elements) {
        return new LinkedHashSet(list(elements));
    }

    public static  List list(E... elements) {
        return asList(elements);
    }

}