Convert String To Unmodifiable Set<Character> - Java java.util

Java examples for java.util:Set Creation

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Description

Convert String To Unmodifiable Set<Character>

Demo Code


//package com.java2s;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

public class Main {
    public static void main(String[] argv) {
        String str = "java2s.com";
        System.out.println(strToUnmodifiableSet(str));
    }/*  w  w  w  . jav  a 2s.c  om*/

    public static Set<Character> strToUnmodifiableSet(final String str) {
        if (str == null) {
            return Collections.emptySet();
        }
        if (str.length() == 1) {
            return Collections.singleton(str.charAt(0));
        }
        return Collections.unmodifiableSet(strToSet(str));
    }

    private static Set<Character> strToSet(final String str) {
        Set<Character> set;

        if (str == null) {
            return new HashSet<Character>();
        }
        set = new HashSet<Character>(str.length());
        for (int i = 0; i < str.length(); i++) {
            set.add(str.charAt(i));
        }
        return set;
    }
}

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