com.lambdaworks.redis.internal.LettuceSets Maven / Gradle / Ivy

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Advanced and thread-safe Java Redis client for synchronous, asynchronous, and reactive usage. Supports Cluster, Sentinel, Pipelining, Auto-Reconnect, Codecs and much more.
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/*
 * Copyright 2011-2016 the original author or authors.
 *
 * 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.
 */
package com.lambdaworks.redis.internal;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

/**
 * Static utility methods for {@link Set} instances. This class is part of the internal API and may change without further
 * notice.
 * 
 * @author Mark Paluch
 * @since 4.2
 */
@SuppressWarnings("varargs")
public final class LettuceSets {

    /**
     * prevent instances.
     */
    private LettuceSets() {

    }

    /**
     * Creates a new {@code HashSet} containing all elements from {@code elements}.
     * 
     * @param elements the elements that the set should contain, must not be {@literal null}.
     * @param  the element type
     * @return a new {@code HashSet} containing all elements from {@code elements}.
     */
    public static  Set newHashSet(Collection elements) {
        LettuceAssert.notNull(elements, "Collection must not be null");

        HashSet set = new HashSet<>(elements.size());
        set.addAll(elements);
        return set;
    }

    /**
     * Creates a new {@code HashSet} containing all elements from {@code elements}.
     * 
     * @param elements the elements that the set should contain, must not be {@literal null}.
     * @param  the element type
     * @return a new {@code HashSet} containing all elements from {@code elements}.
     */
    @SuppressWarnings("unchecked")
    public static  Set newHashSet(Iterable elements) {
        LettuceAssert.notNull(elements, "Iterable must not be null");

        if (elements instanceof Collection) {
            return newHashSet((Collection) elements);
        }

        Set set = new HashSet<>();
        for (T e : elements) {
            set.add(e);
        }
        return set;
    }

    /**
     * Creates a new {@code HashSet} containing all elements from {@code elements}.
     * 
     * @param elements the elements that the set should contain, must not be {@literal null}.
     * @param  the element type
     * @return a new {@code HashSet} containing all elements from {@code elements}.
     */
    @SafeVarargs
    public static  Set newHashSet(T... elements) {

        LettuceAssert.notNull(elements, "Elements must not be null");

        HashSet set = new HashSet<>(elements.length);
        Collections.addAll(set, elements);
        return set;
    }

    /**
     * Creates a new unmodifiable {@code HashSet} containing all elements from {@code elements}.
     *
     * @param elements the elements that the set should contain, must not be {@literal null}.
     * @param  the element type
     * @return a new {@code HashSet} containing all elements from {@code elements}.
     */
    @SafeVarargs
    public static  Set unmodifiableSet(T... elements) {
        return Collections.unmodifiableSet(newHashSet(elements));
    }
}