net.sf.sprockets.util.Elements.java Source code

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Here is the source code for net.sf.sprockets.util.Elements.java

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/*
 * Copyright 2013-2014 pushbit <pushbit@gmail.com>
 * 
 * This file is part of Sprockets.
 * 
 * Sprockets is free software: you can redistribute it and/or modify it under the terms of the GNU
 * Lesser General Public License as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 * 
 * Sprockets 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with Sprockets. If
 * not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.sprockets.util;

import java.util.ArrayList;
import java.util.List;

import com.google.common.collect.ObjectArrays;

/**
 * Utility methods for working with array and list elements.
 * 
 * @since 1.1.0
 */
public class Elements {
    private Elements() {
    }

    /**
     * Get the element at the index in the array.
     * 
     * @return null if the index is out of bounds
     */
    public static <T> T get(T[] array, int index) {
        return index >= 0 && index < array.length ? array[index] : null;
    }

    /**
     * Get the element at the index in the list.
     * 
     * @return null if the index is out of bounds
     */
    public static <T> T get(List<T> list, int index) {
        return index >= 0 && index < list.size() ? list.get(index) : null;
    }

    /**
     * Get the elements in the array that are at the indexes.
     * 
     * @since 1.4.0
     */
    public static <T> T[] slice(T[] array, int... indexes) {
        T[] slice = ObjectArrays.newArray(array, indexes.length);
        for (int i = 0; i < indexes.length; i++) {
            slice[i] = array[indexes[i]];
        }
        return slice;
    }

    /**
     * Get the elements in the list that are at the indexes.
     * 
     * @since 1.4.0
     */
    public static <T> List<T> slice(List<T> list, int... indexes) {
        List<T> slice = new ArrayList<T>(indexes.length);
        for (int i : indexes) {
            slice.add(list.get(i));
        }
        return slice;
    }
}