Java Set to toUnmodifiableSet(final Collection source)

Description

to Unmodifiable Set

License

Open Source License

Declaration

public static final <T> Set<T> toUnmodifiableSet(final Collection<? extends T> source) 

Method Source Code

//package com.java2s;
/*//from ww  w .j  a v a  2 s.  c om
 * Copyright (c) 2018, The Modern Way. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.Collection;
import java.util.Collections;

import java.util.LinkedHashSet;

import java.util.Set;

public class Main {
    public static final <T> Set<T> toUnmodifiableSet(final Collection<? extends T> source) {
        if (source instanceof Set) {
            return Collections.unmodifiableSet(CAST(source));
        }
        return Collections.unmodifiableSet(linkedSet(source));
    }

    @SuppressWarnings("unchecked")
    public static final <T> T CAST(final Object value) {
        return ((T) value);
    }

    public static final <T> LinkedHashSet<T> linkedSet() {
        return new LinkedHashSet<>();
    }

    public static final <T> LinkedHashSet<T> linkedSet(final Collection<? extends T> source) {
        return new LinkedHashSet<>(source);
    }
}

Related

1. toIntArray(Set is)
2. toUnmodifiableSet(String... values)