Java Collection Add addNonnullIfMissing(Collection collection, T element)

Description

Adds an element to a collection only if the latter does not contain it and the element is not null.

License

Open Source License

Parameter

Parameter	Description
collection	the collection to be populated with the given element.
element	the element to be added to the given collection.

Declaration

public static <T> void addNonnullIfMissing(Collection<T> collection, T element) 

Method Source Code

//package com.java2s;
/*//from  w  w w .  jav  a2s  .  c o m
 * CollectionUtils.java
 *
 * Copyright (C) 2012-2014 LucasEasedUp
 *
 * This program 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/>.
 */

import java.util.Collection;

public class Main {
    /**
     * Adds an element to a collection only if the latter does not contain it
     * and the element is not null.
     * 
     * @param collection the collection to be populated with the given element.
     * @param element the element to be added to the given collection.
     */
    public static <T> void addNonnullIfMissing(Collection<T> collection, T element) {
        if (collection == null)
            throw new IllegalArgumentException();

        if (element != null && !collection.contains(element)) {
            collection.add(element);
        }
    }
}

Related

1. addInClauseToQuery(StringBuilder query, Collection