/*
 * Copyright 1999-2012 Alibaba Group.
 *    
 *   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.alibaba.dubbo.rpc.cluster.merger;

import java.util.HashSet;
import java.util.Set;

import com.alibaba.dubbo.rpc.cluster.Merger;

/**
 * @author <a href="mailto:gang.lvg@alibaba-inc.com">kimi</a>
 */
public class SetMerger implements Merger<Set<?>> {

    public static final String    NAME     = "set";

    public static final SetMerger INSTANCE = new SetMerger();

    public Set<Object> merge(Set<?>... items) {

        Set<Object> result = new HashSet<Object>();

        for (Set<?> item : items) {
            if (item != null) {
                result.addAll(item);
            }
        }

        return result;
    }
}