Creates a collection from an iterable. - Java Collection Framework

Java examples for Collection Framework:Iterable

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

Description

Creates a collection from an iterable.

Demo Code

/**//from ww w  .ja  v a2  s  .  c om
 * Copyright (c) 2002-2013 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
//package com.java2s;

import java.util.ArrayList;
import java.util.Collection;

import java.util.Iterator;
import java.util.List;

public class Main {
    /**
     * Creates a collection from an iterable.
     *
     * @param iterable The iterable to create the collection from.
     * @param <T> The generic type of both the iterable and the collection.
     * @return a collection containing all items from the iterable.
     */
    public static <T> Collection<T> asCollection(Iterable<T> iterable) {
        List<T> list = new ArrayList<T>();
        addToCollection(iterable, list);
        return list;
    }

    /**
     * Adds all the items in {@code iterator} to {@code collection}.
     * @param <C> the type of {@link Collection} to add to items to.
     * @param <T> the type of items in the collection and iterator.
     * @param iterator the {@link Iterator} to grab the items from.
     * @param collection the {@link Collection} to add the items to.
     * @return the {@code collection} which was passed in, now filled
     * with the items from {@code iterator}.
     */
    public static <C extends Collection<T>, T> C addToCollection(
            Iterator<T> iterator, C collection) {
        while (iterator.hasNext()) {
            collection.add(iterator.next());
        }
        return collection;
    }

    /**
     * Adds all the items in {@code iterator} to {@code collection}.
     * @param <C> the type of {@link Collection} to add to items to.
     * @param <T> the type of items in the collection and iterator.
     * @param iterable the {@link Iterator} to grab the items from.
     * @param collection the {@link Collection} to add the items to.
     * @return the {@code collection} which was passed in, now filled
     * with the items from {@code iterator}.
     */
    public static <C extends Collection<T>, T> C addToCollection(
            Iterable<T> iterable, C collection) {
        return addToCollection(iterable.iterator(), collection);
    }
}

Related Tutorials