com.cedarsoftware.util

Class MapUtilities

java.lang.Object

com.cedarsoftware.util.MapUtilities

public class MapUtilities
extends Object

Usefule utilities for Maps

Author:

Kenneth Partlow
Copyright (c) Cedar Software LLC

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.

Method Summary

Modifier and Type	Method and Description
static <T> T	get(Map<?,T> map, Object key, T def) Retrieves a value from a map by key
static <T extends Throwable> Object	getOrThrow(Map<?,?> map, Object key, T throwable) Retrieves a value from a map by key, if value is not found by the given key throws a 'Throwable.' This version allows the value associated to the key to be null, and it still works.
static boolean	isEmpty(Map map) Returns null safe isEmpty check for Map

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

get

public static <T> T get(Map<?,T> map,
                        Object key,
                        T def)

Retrieves a value from a map by key

Parameters:

map - Map to retrieve item from

key - the key whose associated value is to be returned

def - value to return if item was not found.

Returns:

Returns a string value that was found at the location key. If the item is null then the def value is sent back. If the item is not the expected type, an exception is thrown.

getOrThrow

public static <T extends Throwable> Object getOrThrow(Map<?,?> map,
                                                      Object key,
                                                      T throwable)
                                               throws T extends Throwable

Retrieves a value from a map by key, if value is not found by the given key throws a 'Throwable.' This version allows the value associated to the key to be null, and it still works. In other words, if the passed in key is within the map, this method will return whatever is associated to the key, including null.

Type Parameters:

T - Throwable passed in to be thrown *if* the passed in key is not within the passed in map.

Parameters:

map - Map to retrieve item from

key - the key whose associated value is to be returned

throwable -

Returns:

the value associated to the passed in key from the passed in map, otherwise throw the passed in exception.

Throws:

T extends Throwable

isEmpty

public static boolean isEmpty(Map map)

Returns null safe isEmpty check for Map

Parameters:

map - Map to check, can be null

Returns:

Returns true if map is empty or null