com.nimbusds.oauth2.sdk.util.MultivaluedMapUtils Maven / Gradle / Ivy

/*
 * oauth2-oidc-sdk
 *
 * Copyright 2012-2016, Connect2id Ltd and contributors.
 *
 * 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.
 */

package com.nimbusds.oauth2.sdk.util;


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


/**
 * Multi-valued map utilities.
 */
public final class MultivaluedMapUtils {
	
	
	/**
	 * Converts the specified multi-valued map to a single-valued map by
	 * taking the first value in the list.
	 *
	 * @param map The multi-valued map, {@code null} if not specified.
	 *
	 * @return The single-valued map, {@code null} if no map was specified.
	 */
	public static  Map toSingleValuedMap(final Map> map) {
		
		if (map == null)
			return null;
		
		Map out = new HashMap<>();
		
		for (Map.Entry> en: map.entrySet()) {
			
			if (en.getValue() == null || en.getValue().isEmpty()) {
				out.put(en.getKey(), null);
			} else {
				out.put(en.getKey(), en.getValue().get(0));
			}
		}
		
		return out;
	}
	
	
	/**
	 * Gets the first value for the specified key.
	 *
	 * @param map The multi-valued map. Must not be {@code null}.
	 * @param key The key. Must not be {@code null}.
	 *
	 * @return The first value, {@code null} if not set.
	 */
	public static  V getFirstValue(final Map> map, final K key) {
		
		List valueList = map.get(key);
		
		if (valueList == null || valueList.isEmpty()) {
			return null;
		}
		
		return valueList.get(0);
	}
	
	
	/**
	 * Removes the entry for the specified key and returns its first value.
	 *
	 * @param map The multi-valued map. Must not be {@code null}.
	 * @param key The key. Must not be {@code null}.
	 *
	 * @return The first value, {@code null} if not set.
	 */
	public static  V removeAndReturnFirstValue(final Map> map, final String key) {
		
		List valueList = map.remove(key);
		
		if (valueList == null || valueList.isEmpty()) {
			return null;
		}
		
		return valueList.get(0);
	}
	
	
	/**
	 * Prevents public instantiation.
	 */
	private MultivaluedMapUtils() {}
}