 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Java Forum / General / February 2007Character Parser
Hi, I want to create a character parser in java. I basically want to parse a text file removing extra spaces and carriage returns. Ive used stream tokenizers before, but what if i want the token to be every character rather than a delimiter. Thanks for your time and help :) > Hi, > [quoted text clipped - 5 lines] > Thanks for your time and help > :) In that case, you don't want tokenizing. You don't even want parsing! You want to read the data one character at a time. <http://java.sun.com/j2se/1.5.0/docs/api/java/io/Reader.html> Look at the method called read(char[]) >> Hi, >> [quoted text clipped - 13 lines] > > Look at the method called read(char[]) For efficiency, I suggest using BufferedReader, which is the same deal (but it buffers chunks of data behind the scenes - less disk accesses, so faster!) lex For best performance, you may want to use a java.nio.ByteBuffer. I've had to read in a 2GB file and using a a BufferedInputStream and a ByteBuffer was the only viable solution. Other APIs could not handle such a large file. If your file is small(using a BufferedInputStream/ByteBuffer would not offer significant gains) and simplicity outweighs performance, then you can always use one of the replace methods in the String class. > Hi, > [quoted text clipped - 5 lines] > Thanks for your time and help > :) > For best performance, you may want to use a java.nio.ByteBuffer. I've > had to read in a 2GB file and using a a BufferedInputStream and a > ByteBuffer was the only viable solution. Other APIs could not handle > such a large file. Which other APIs do you mean? Shouldn't the OP should be using a Reader or BufferedReader (designed for char data) rather than something that reads bytes? The end effect may be the same, of course... lex > richliu2...@gmail.com wrote: > > For best performance, you may want to use a java.nio.ByteBuffer. I've [quoted text clipped - 8 lines] > > lex i had a similar task to do some time ago i needed to compare lexographcily two enormous files simultaneously. you can use a CharArrayReader to read an char[] (you might wanna make an additional method for reading a complete line instead of a portion of the text) now you can break all the text file to chars if you do need buffering i recommend you learn the sourcecode behind BufferedReader and make your own Reader class that can return a char[] (i couldnt find one in jse api ... i havnt invested alot of time on it) for holding your already parsed text you can crate a StringBuffer and simply by iterating the char[] you decide if you want to append the givan char to the StringBuffer or not http://java.sun.com/j2se/1.5.0/docs/api/java/io/CharArrayReader.html http://java.sun.com/j2se/1.5.0/docs/api/java/lang/StringBuffer.html a more faster mutable sequence of characters for non-sync tasks (just like StringBuffer but faster) http://java.sun.com/j2se/1.5.0/docs/api/java/lang/StringBuilder.html and maybe you can find some thing here http://java.sun.com/docs/books/tutorial/essential/io/scanning.html Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.