Convert Array of string as Immutable Set - Java java.util

Java examples for java.util:Set Creation

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Description

Convert Array of string as Immutable Set

Demo Code


//package com.java2s;

import java.util.Arrays;

import java.util.Collections;

import java.util.HashSet;

import java.util.Set;

public class Main {
    public static void main(String[] argv) {
        String[] names = new String[] { "1", "abc", "level", null,
                "java2s.com", "asdf 123" };
        System.out.println(asImmutableSet(names));
    }/* www.j av a2 s  .c o  m*/

    public static Set<String> asImmutableSet(String[] names) {
        //The intention here is to save some memory by picking the simplest safe representation,
        // as we usually require immutable sets for long living metadata:
        if (names == null || names.length == 0) {
            return Collections.<String> emptySet();
        } else if (names.length == 1) {
            return Collections.singleton(names[0]);
        } else {
            HashSet<String> hashSet = new HashSet<>(Arrays.asList(names));
            return Collections.unmodifiableSet(hashSet);
        }
    }
}

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