/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.ambari.server.utils;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
/**
* Static Helper methods for sets
*/
public class SetUtils {
/**
* Split a set into subsets
* @param original The original set to be split
* @param subsetSize Size of the subset (except for final subset)
* @param <T> Data type of set elements
* @return List of subsets
*/
public static <T> List<Set<T>> split(Set<T> original, int subsetSize) {
if(subsetSize <= 0) {
throw new IllegalArgumentException("Incorrect max size");
}
if(original == null || original.isEmpty()) {
return Collections.emptyList();
}
int subsetCount = (int) (Math.ceil((double)original.size() / subsetSize));
ArrayList<Set<T>> subsets = new ArrayList<>(subsetCount);
Iterator<T> iterator = original.iterator();
for(int i = 0; i < subsetCount; i++) {
Set<T> subset = new LinkedHashSet<>(subsetSize);
for(int j = 0; j < subsetSize && iterator.hasNext(); j++) {
subset.add(iterator.next());
}
subsets.add(subset);
}
return subsets;
}
}