/*
* 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.
*/
/**
* (created at 2011-10-24)
*/
package com.alibaba.cobar.util;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
/**
* @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
*/
public class CollectionUtil {
/**
* @param orig if null, return intersect
*/
public static Set<? extends Object> intersectSet(Set<? extends Object> orig, Set<? extends Object> intersect) {
if (orig == null)
return intersect;
if (intersect == null || orig.isEmpty())
return Collections.emptySet();
Set<Object> set = new HashSet<Object>(orig.size());
for (Object p : orig) {
if (intersect.contains(p))
set.add(p);
}
return set;
}
}