Mega Code Archive
Splits the list
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/*
* Copyright 2004-2010 the Seasar Foundation and the Others.
*
* 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 org.slim3.util;
import java.util.ArrayList;
import java.util.List;
/**
* A utility for {@link List}.
*
* @author higa
* @since 1.0.0
*
*/
public final class ListUtil {
/**
* Splits the list.
*
* @param <T>
* the type of list element
* @param list
* the list
* @param size
* the piece size
* @return the split lists.
* @throws NullPointerException
* if the list parameter is null
* @throws IllegalArgumentException
* if the size parameter is less than 1
*/
public static <T> List<List<T>> split(List<T> list, int size)
throws NullPointerException, IllegalArgumentException {
if (list == null) {
throw new NullPointerException("The list parameter is null.");
}
if (size <= 0) {
throw new IllegalArgumentException(
"The size parameter must be more than 0.");
}
int num = list.size() / size;
int mod = list.size() % size;
List<List<T>> ret = new ArrayList<List<T>>(mod > 0 ? num + 1 : num);
for (int i = 0; i < num; i++) {
ret.add(list.subList(i * size, (i + 1) * size));
}
if (mod > 0) {
ret.add(list.subList(num * size, list.size()));
}
return ret;
}
private ListUtil() {
}
}
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