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package net.dongliu.commons.collection;

import javax.annotation.Nullable;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * Utils method for map
 *
 * @author Liu Dong
 */
public class Maps {

    /**
     * Map is null or empty
     */
    public static boolean isNullOrEmpty(@Nullable Map map) {
        return map == null || map.isEmpty();
    }

    /**
     * If map is null, return immutable empty map; else return self
     */
    public static  Map nullToEmpty(@Nullable Map map) {
        return map == null ? Maps.of() : map;
    }

    /**
     * Create immutable view of this Set.
     */
    public static  Map asImmutable(Map map) {
        return Collections.unmodifiableMap(map);
    }

    /**
     * Create a immutable map with defensive copy
     */
    public static  Map toImmutable(Map map) {
        return Collections.unmodifiableMap(new HashMap<>(map));
    }


    /**
     * Create immutable empty map
     */
    public static  Map of() {
        return Collections.emptyMap();
    }

    /**
     * Create immutable map
     */
    public static  Map of(Map.Entry value) {
        Map map = create(1);
        map.put(value.getKey(), value.getValue());
        return asImmutable(map);
    }

    /**
     * Create immutable map
     */
    public static  Map of(Map.Entry value1,
                                      Map.Entry value2) {
        Map map = create(2);
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        return asImmutable(map);
    }

    /**
     * Create immutable map
     */
    public static  Map of(Map.Entry value1,
                                      Map.Entry value2,
                                      Map.Entry value3) {
        Map map = create(3);
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        return asImmutable(map);
    }

    /**
     * Create immutable map
     */
    public static  Map of(Map.Entry value1,
                                      Map.Entry value2,
                                      Map.Entry value3,
                                      Map.Entry value4) {
        Map map = create(4);
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        map.put(value4.getKey(), value4.getValue());
        return asImmutable(map);
    }

    /**
     * Create immutable map
     */
    public static  Map of(Map.Entry value1,
                                      Map.Entry value2,
                                      Map.Entry value3,
                                      Map.Entry value4,
                                      Map.Entry value5) {
        Map map = create(5);
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        map.put(value4.getKey(), value4.getValue());
        map.put(value5.getKey(), value5.getValue());
        return asImmutable(map);
    }

    @SafeVarargs
    public static  Map of(Map.Entry... values) {
        if (values.length == 0) {
            return of();
        }
        return asImmutable(create(values));
    }

    public static  Map of(Collection> values) {
        return asImmutable(create(values));
    }

    /**
     * Create mutable empty map, with expected size
     */
    public static  Map create(int expectedSize) {
        return new HashMap<>((int) (expectedSize / 0.75f) + 1, 0.75f);
    }

    /**
     * Create mutable empty map
     */
    public static  Map create() {
        return new HashMap<>();
    }

    /**
     * Create mutable map
     */
    public static  Map create(Map.Entry value) {
        Map map = create();
        map.put(value.getKey(), value.getValue());
        return map;
    }

    /**
     * Create mutable map
     */
    public static  Map create(Map.Entry value1,
                                          Map.Entry value2) {
        Map map = create();
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        return map;
    }

    /**
     * Create mutable map
     */
    public static  Map create(Map.Entry value1,
                                          Map.Entry value2,
                                          Map.Entry value3) {
        Map map = create();
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        return map;
    }

    /**
     * Create mutable map
     */
    public static  Map create(Map.Entry value1,
                                          Map.Entry value2,
                                          Map.Entry value3,
                                          Map.Entry value4) {
        Map map = create();
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        map.put(value4.getKey(), value4.getValue());
        return map;
    }

    /**
     * Create mutable map
     */
    public static  Map create(Map.Entry value1,
                                          Map.Entry value2,
                                          Map.Entry value3,
                                          Map.Entry value4,
                                          Map.Entry value5) {
        Map map = create();
        map.put(value1.getKey(), value1.getValue());
        map.put(value2.getKey(), value2.getValue());
        map.put(value3.getKey(), value3.getValue());
        map.put(value4.getKey(), value4.getValue());
        map.put(value5.getKey(), value5.getValue());
        return map;
    }

    @SafeVarargs
    public static  Map create(Map.Entry... values) {
        Map map = create(values.length);
        for (Map.Entry tuple : values) {
            map.put(tuple.getKey(), tuple.getValue());
        }
        return map;
    }

    public static  Map create(Collection> values) {
        Map map = create(values.size());
        for (Map.Entry tuple : values) {
            map.put(tuple.getKey(), tuple.getValue());
        }
        return map;
    }

}