Gets an element from a list based on the index. - Java java.util

Java examples for java.util:List Element

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Description

Gets an element from a list based on the index.

Demo Code

/*/*from w w  w  . ja  v  a2s.c o  m*/
 * Copyright 2005-2014 The Kuali Foundation
 * 
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl1.php
 * 
 * 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.
 */
import java.util.List;

public class Main{
    public static void main(String[] argv){
        int index = 42;
        List fromList = java.util.Arrays.asList("asdf","java2s.com");
        System.out.println(getFromList(index,fromList));
    }
    /**
     * Gets an element from a list based on the index.  If the index is invalid null will be returned.
     * @param <T> the type of List
     * @param index the index
     * @param fromList the list to retrieve from
     * @return the element
     */
    public static <T> T getFromList(final int index, final List<T> fromList) {
        if (!CollectionUtil.validIndexForList(index, fromList)) {
            return null;
        }

        return fromList.get(index);
    }
    /**
     * Checks if a given index is valid for a given list. This method returns null if the list is null.
     * 
     * @param index the index
     * @param forList the list
     * @return true if a valid index
     */
    public static boolean validIndexForList(final int index,
            final List<?> forList) {
        return forList != null && index >= 0 && index <= forList.size() - 1;
    }
}

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