builder for HashMap

Question

Guava provides us with great factory methods for Java types, such as Maps.newHashMap().

But are there also builders for java Maps?

HashM         


        

Answer 1

Using java 8:

This is a approach of Java-9 Map.ofEntries(Map.entry(k1,v1), Map.entry(k2,v2), ...)

public class MapUtil {
    import static java.util.stream.Collectors.toMap;

    import java.util.AbstractMap.SimpleEntry;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.stream.Stream;

    private MapUtil() {}

    @SafeVarargs
    public static Map ofEntries(SimpleEntry... values) {
        return Stream.of(values).collect(toMap(Entry::getKey, Entry::getValue));
    }

    public static SimpleEntry entry(String key, Object value) {
        return new SimpleEntry(key, value);
    }
}

How to Use:

import static your.package.name.MapUtil.*;

import java.util.Map;

Map map = ofEntries(
        entry("id", 1),
        entry("description", "xyz"),
        entry("value", 1.05),
        entry("enable", true)
    );