Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 *  Copyright 2011 Eric F. Savage, code@efsavage.com
 *
 *   Licensed 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.
 */

import java.util.ArrayList;

import java.util.List;
import java.util.Map;

public class Main {
    /**
     * Removes the entries of a map that have null values.
     * 
     * @param map
     *            The map to strip.
     * @return The map that was passed in.
     */
    public static <K, V> Map<K, V> stripNulls(final Map<K, V> map) {
        List<Object> toRemove = null;
        for (final Object key : map.keySet()) {
            if (map.get(key) == null) {
                toRemove = safeAdd(toRemove, key);
            }
        }
        if (toRemove != null) {
            for (final Object key : toRemove) {
                map.remove(key);
            }
        }
        return map;
    }

    /**
     * Shorthand method for adding an item to a list, and creating that list if
     * necessary.
     * 
     * @param list
     *            The list to add to.
     * @param item
     *            The item to add.
     * @return The original list that was passed in, or a new list.
     */
    private static <T> List<T> safeAdd(final List<T> list, final T item) {
        List<T> retVal = list;
        if (retVal == null) {
            retVal = new ArrayList<>();
        }
        retVal.add(item);
        return retVal;
    }
}