Path: csiph.com!aioe.org!.POSTED!not-for-mail
From: =?UTF-8?Q?Arne_Vajh=c3=b8j?= <arne@vajhoej.dk>
Newsgroups: comp.lang.java.programmer
Subject: Re: XML
Date: Tue, 16 Aug 2016 21:37:02 -0400
Organization: Aioe.org NNTP Server
Lines: 29
Message-ID: <np0f3u$1kfc$1@gioia.aioe.org>
References: <34f5f605-db80-441c-9730-ceecf445c1a8@googlegroups.com> <t9gqpb19cdmnl2sgformolvii8pe4et688@4ax.com> <nnjlfe$spe$1@gioia.aioe.org> <kvjtpblrc7j5i3u62ee6japlm9481ajavq@4ax.com> <0176078c-ab98-4e66-ba3e-b14ee88b58e0@googlegroups.com> <nnngk6$603$1@gioia.aioe.org> <d7e3e460-1025-4670-b425-672f4196d9e2@googlegroups.com> <no7m5v$f24$1@dont-email.me> <487a50aa-8e4b-460a-9824-bd23c26d4c02@googlegroups.com> <nodg3g$elh$1@dont-email.me> <de36e9b4-44de-44ba-835d-80e9dc80fa90@googlegroups.com> <nofttr$u80$1@dont-email.me> <00fae8a8-dc01-435f-9f33-e5a5055d93df@googlegroups.com> <nonsuv$425$1@gioia.aioe.org> <9c174795-1c98-46f0-bbac-179581cd39a2@googlegroups.com> <novr71$8j0$1@dont-email.me> <6eae6f69-b51d-4e1a-9308-fb68fc735db8@googlegroups.com> <novv42$12m6$1@gioia.aioe.org>
NNTP-Posting-Host: 7SK6yTFfqwlIPNBLl3l7Qg.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0
X-Notice: Filtered by postfilter v. 0.8.2
Xref: csiph.com comp.lang.java.programmer:35370

On 8/16/2016 5:04 PM, Arne Vajhøj wrote:
> Note that you can convert data to a TreeMap using streams
> and lambdas if you really need fast lookup by key.

Demo (well - it is converting to HashMap I think):

Previous code:

// search
Data o1 = data2.getList().stream().filter(item -> item.getIv() == 
456).findFirst().get();
Data o2 = data2.getList().stream().filter(item -> item instanceof DataA 
&& ((DataA)item).getSv().equals("ABC")).findFirst().get();

Map code:

// search
Map<Integer, Data> lookupByIv = 
data2.getList().stream().collect(Collectors.toMap(item -> item.getIv(), 
item -> item));
Map<String, Data> lookupBySv = data2.getList().stream().filter(item -> 
item instanceof DataA).map(item -> 
(DataA)item).collect(Collectors.toMap(item -> item.getSv(), item -> item));
Data o1 = lookupByIv.get(456);
Data o2 = lookupBySv.get("ABC");

Arne