iterable To List - Java Collection Framework

Java examples for Collection Framework:Iterable

  1. HOME
  2. Java
  3. Collection Framework
  4. Iterable

Description

iterable To List

Demo Code

/**//from  w  w w . j a  va 2s .  c  o  m
 * 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 com.java2s;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Main {
    /**
     * @param iterable {@link Iterable} whose contents are to be put into a {@link List}
     * @return a {@link List} with the objects one gets by iterating over the given {@link Iterable}
     */
    public static <K> List<K> iterableToList(Iterable<K> iterable) {
        return iterableToList(iterable, null);
    }

    /**
     * @param iterable   {@link Iterable} whose contents are to be put into a {@link List}
     * @param comparator {@link Comparator} defining the sort order of the returned {@link List}
     * @return a {@link List} with the objects one gets by iterating over the given {@link Iterable}, sorted according to
     *         the given {@link Comparator}
     */
    public static <K> List<K> iterableToList(Iterable<K> iterable,
            Comparator<K> comparator) {
        if (iterable == null) {
            throw new IllegalArgumentException("iterable is null");
        }
        List<K> list;
        if (iterable instanceof Collection) {
            if (iterable instanceof List) {
                list = (List<K>) iterable;
            } else {
                Collection<K> collection = (Collection<K>) iterable;
                list = new ArrayList<K>(collection.size());
                list.addAll(collection);
            }
        } else {
            list = new ArrayList<K>();
            for (K item : iterable) {
                list.add(item);
            }
        }
        if (comparator != null) {
            Collections.sort(list, comparator);
        }
        return list;
    }
}

Related Tutorials