Class CollectionUtil

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12
13	package org.locationtech.jts.util;
14
15	import java.util.ArrayList;
16	import java.util.Collection;
17	import java.util.Iterator;
18	import java.util.List;
19
20	/**
21	* Utilities for processing {@link Collection}s.
22	*
23	* @version 1.7
24	*/
25	public class CollectionUtil
26	{
27
28	public interface Function {
29	Object execute(Object obj);
30	}
31
32	/**
33	* Executes a function on each item in a {@link Collection}
34	* and returns the results in a new {@link List}
35	*
36	* @param coll the collection to process
37	* @param func the Function to execute
38	* @return a list of the transformed objects
39	*/
40	public static List transform(Collection coll, Function func)
41	{
42	List result = new ArrayList();
43	for (Iterator i = coll.iterator(); i.hasNext(); ) {
44	result.add(func.execute(i.next()));
45	}
46	return result;
47	}
48
49	/**
50	* Executes a function on each item in a Collection but does
51	* not accumulate the result
52	*
53	* @param coll the collection to process
54	* @param func the Function to execute
55	*/
56	public static void apply(Collection coll, Function func)
57	{
58	for (Iterator i = coll.iterator(); i.hasNext(); ) {
59	func.execute(i.next());
60	}
61	}
62
63	/**
64	* Executes a {@link Function} on each item in a Collection
65	* and collects all the entries for which the result
66	* of the function is equal to {@link Boolean} <tt>true</tt>.
67	*
68	* @param collection the collection to process
69	* @param func the Function to execute
70	* @return a list of objects for which the function was true
71	*/
72	public static List select(Collection collection, Function func) {
73	List result = new ArrayList();
74	for (Iterator i = collection.iterator(); i.hasNext();) {
75	Object item = i.next();
76	if (Boolean.TRUE.equals(func.execute(item))) {
77	result.add(item);
78	}
79	}
80	return result;
81	}
82	}
83