Path: csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!news.lightlink.com!news.iecc.com!border3.nntp.dca.giganews.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.earthlink.com!news.earthlink.com.POSTED!not-for-mail NNTP-Posting-Date: Wed, 05 Oct 2011 12:30:25 -0500 Date: Wed, 05 Oct 2011 10:30:26 -0700 From: Patricia Shanahan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.22) Gecko/20110902 Thunderbird/3.1.14 MIME-Version: 1.0 Newsgroups: comp.lang.java.programmer Subject: Re: optional operation References: <5eb0fcba-199f-46e4-b913-2f3e851d89fc@q26g2000vby.googlegroups.com> In-Reply-To: <5eb0fcba-199f-46e4-b913-2f3e851d89fc@q26g2000vby.googlegroups.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Message-ID: Lines: 21 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 70.230.200.54 X-Trace: sv3-thnBZr43C9VjQHAZHgN64fka1BrlckRIzeutlZWID0oiTWET5mwvH26v+LRduFtINzD6iq5U0iE7AkR!E+8CvLBOTSc8dska+oj7vyMmXWZt3KV9Gwi4ZEOBkgIWsaoyMLU+rB0OYPLSsG0dcie39rJ3ONbY!X09w/tKsURe5e1ZNhCSSXvNTWI0zh78RngXzFmjh/ksF8w== X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 2110 Xref: x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:8577 On 10/5/2011 9:49 AM, bob wrote: > I'm looking at the docs for FloatBuffer, and in many places it says > "(optional operation)". What's the deal with this? Can we use the > operation or not? The term "optional operation" is used in interface and abstract class declarations to indicate a method that the implementation may be allowed to throw UnsupportedOperationException. There are two useful places to look for more information: 1. The full description of the method. For example, FloatBuffer's array method is defined to throw UnsupportedOperationException "If this buffer is not backed by an accessible array". 2. Especially in java.util, there are interfaces with many different implementing classes, and you may need to look at the API documentation for the implementing class you are using to find out which operations it supports. Patricia