RandomFile (Java)

.

RandomFile returns the contents of a randomly-selected file in a specifed directory. Qualification by prefux and suffix is supported. I wound up calling this code from within a Borscht server-side processed page, by saying

{* setHandler randomFile=”client.someone.handler.misc.RandomFile” *}

{* randomFile root=$cgi.DOCUMENT_ROOT prefix=”item_ID_” dir=”/factoids/promo/” *}

{* randomFile root=$cgi.DOCUMENT_ROOT prefix=”item_ID_” dir=”/factoids/funfacts/” *}

The file RandomFile.java looks like:

package client.someone.handler.misc

import java.util.Hashtable;

import java.util.Vector;

import organic.servlet.broker.*;

import java.io.File ;

import java.io.FileReader ;

import java.io.BufferedReader ;

public class RandomFile implements HandlerInterface {

// Standard error messages

static final String kErrMissingDirArg =

“RandomFile: error: missing dir arg: ” +

“usage: \{* randomFile dir=\”e:\\\” *}”;

static final String kErrInvalidDirArg =

“RandomFile: error: invalid directory argument value: ” ;

public Object handleToken(String tokenName,

Hashtable args,

Request request)

throws HandlerException

{

try {

// Get the root argument passed to us

String rootArg = (String) args.get( “root” ) ;

// Get the dir argument passed to us; complain if missing.

String dirArg = (String) args.get( “dir” ) ;

if ( dirArg == null || dirArg.equals(“”) )

return kErrMissingDirArg ;

// Get filesInDir or return appropriate error message

File dir = new File( rootArg + dirArg ) ;

String files[] = dir.list() ;

int filesInDir ;

try { filesInDir = files.length ; }

catch (Exception e) { return kErrInvalidDirArg + “\”” + rootArg + dirArg + “”” ; }

// Get the prefix argument passed to us

String prefixArg = (String) args.get( “prefix” ) ;

// Get the suffix argument passed to us

String suffixArg = (String) args.get( “suffix” ) ;

Vector filesThatQualify = QualifyFiles( files, prefixArg, suffixArg ) ;

BufferedReader in = new BufferedReader(

new FileReader( rootArg + dirArg + filesThatQualify.elementAt(

(int) ( Math.random() * filesThatQualify.size() )))) ;

StringBuffer contents = new StringBuffer() ;

String oneLine ;

while ( ( oneLine = in.readLine() ) != null )

contents.append( oneLine ).append(” “) ;

in.close() ;

return contents ;

} catch (Exception e) { throw new HandlerException(e); }

}

// —————————————————–

// Qualify the filenames based on prefix and/or suffix.

// —————————————————–

public Vector QualifyFiles(String[] files, String prefixArg, String suffixArg) {

StringBuffer b = new StringBuffer() ;

String fn = new String() ;

Vector filesThatQualify = new Vector(1) ;

for ( int i = 0 ; i < files.length ; i++ ) \{ fn = files[i] ; if ( prefixArg != null && !prefixArg.equals("") ) if ( !fn.startsWith( prefixArg )) fn = "" ; if ( suffixArg != null && !suffixArg.equals("") ) if ( !fn.endsWith( suffixArg )) fn = "" ; if ( !fn.equals("") ) filesThatQualify.addElement( files[i] ) ; } return filesThatQualify ; } } This page is 1993-2006 by , via the Creative Commons License. Questions and comments? Send to the Geek Times Webmaster. (Domain and web content hosting at .)