| // |
| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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. |
| // |
| |
| = DevFaqThreading |
| :jbake-type: wiki |
| :jbake-tags: wiki, devfaq, needsreview |
| :jbake-status: published |
| :keywords: Apache NetBeans wiki DevFaqThreading |
| :description: Apache NetBeans wiki DevFaqThreading |
| :toc: left |
| :toc-title: |
| :syntax: true |
| |
| === I need to run some code on a background thread. Can the platform help me? |
| |
| First, ask yourself why you need to do this and if it is really necessary. Generally there is only one reason: _You are doing something takes some time (file I/O, computing something large and complicated, talking to a network socket) that will block the UI._ |
| |
| NetBeans contains a thread pool `org.openide.util.RequestProcessor`. (You can use the thread pools that exist today in `java.util.concurrent` but it is more typical to use `RequestProcessor`.) There is a general purpose built-in thread pool - `RequestProcessor.getDefault()`. You can use that for things that only happen once in a while; otherwise you are probably better off creating your own instance of `RequestProcessor`. There is a link:DevFaqRequestProcessor.asciidoc[FAQ item about how to know when to do which]. In its most simple usage, `RequestProcessor.post()` is called with a `Runnable`. The call returns a `RequestProcessor.Task` which you can use to monitor the status of the task and listen to task finish among other. |
| |
| Note that if you are doing something in the background, you may want to use the link:http://bits.netbeans.org/dev/javadoc/org-netbeans-api-progress/org/netbeans/api/progress/ProgressHandleFactory.html[Progress API] to show a progress indicator in the status-bar (or use it to put up a modal progress dialog if the UI really needs to be blocked - use with care, only when really necessary). |
| |
| Remember that if you are running more threads than you have processors (or cores) - and your OS is probably using some as well - then when you ask to multi-thread, you are asking your CPU to divide the time of the CPUs you have between more virtual threads. And switching the context a CPU is working in - sending it off to some other memory space and set of instructions, and then another - takes time. So heavy use of multi-threading, especially on single CPU machines, can slow things down rather than speed them up. If you can make your code run faster, do that first. |
| |
| === Apache Migration Information |
| |
| The content in this page was kindly donated by Oracle Corp. to the |
| Apache Software Foundation. |
| |
| This page was exported from link:http://wiki.netbeans.org/DevFaqThreading[http://wiki.netbeans.org/DevFaqThreading] , |
| that was last modified by NetBeans user Dsimonek |
| on 2009-12-03T15:28:32Z. |
| |
| |
| *NOTE:* This document was automatically converted to the AsciiDoc format on 2018-02-07, and needs to be reviewed. |
