org.apache.env
Class Which

java.lang.Object
  |
  +--org.apache.env.Which

public class Which

extends java.lang.Object

General environment checking and version finding service; main external entrypoints and command line interface.

Which is the command line interface to the org.apache.env package. Simply put, it provides a simplistic check of a user's actual environment for debugging and product support purposes by detecting the specific versions of commonly installed classes in the environment.

Which and related service classes provide a framework for looking for version information and passing it around in hashtables. Users can plug in their own implementations of WhichProject classes to get custom version info about any product.

One important usage note: you must call Which (or subclasses) in the environment that you wish to check. I.e. if you have a problem with a command line tool, then call Which from the same command line environment. If you have a problem with a servlet, you must call Which.blah() from your servlet as it's installed in an actual container.

Usage - command line:
java org.apache.env.Which [project;WhichProject] [-options]

Usage - from program:
int status = org.apache.env.Which.which(hash, projects, options);

Usage - from XSLT stylesheet in Xalan-J:
(add which.jar to your classpath and run the following stylesheet)

 <?xml version="1.0"?>
 <xsl:stylesheet version="1.0"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
     xmlns:xalan="http://xml.apache.org/xalan"
     exclude-result-prefixes="xalan">
     <xsl:output indent="yes"/>
     <xsl:template match="/">
       <xsl:copy-of select="xalan:checkEnvironment()"/>
     </xsl:template>
 </xsl:stylesheet>
 

Original credit to org.apache.xalan.xslt.EnvironmentCheck

Version:

$Id: Which.html,v 1.4 2003/12/30 03:55:19 crossley Exp $

Author:

shane_curcuru@us.ibm.com

Field Summary

static java.lang.String	DEFAULT_PROJECTS Default set of projects to use if none provided.
protected java.lang.StringBuffer	optionsBuf optionsBuf.
protected java.io.PrintWriter	outWriter outWriter.
protected java.lang.StringBuffer	projectsBuf projectsBuf.
static java.lang.String	SEPARATOR Generic ';' separator for various items.

Constructor Summary

Which()

Method Summary

void	doMain(java.lang.String[] args) Instance worker method to handle main().
static void	getGeneralInfo(java.util.Hashtable hash, java.lang.String options) Grab a couple of generally useful items, like classpath, java version, version of this file, etc..
static int	getProjectsInfo(java.util.Hashtable hash, java.lang.String projects, java.lang.String options) Get information from various project's WhichProject impls.
static java.lang.String	getVersion() Get simple version info about org.apache.env.Which and related classes.
static void	main(java.lang.String[] args) Command line runnability.
protected boolean	parseArgs(java.lang.String[] args) Parse commandline args, return false if help asked for.
protected void	reportHashtable(java.util.Hashtable hash, java.lang.String name, java.io.PrintWriter out) Print information from a hashtable into the PrintWriter.
void	reportProjectsInfo(java.util.Hashtable hash, java.lang.String options, int status, java.io.PrintWriter out) Print information from which() into the PrintWriter.
protected java.lang.String	usage() Return our usage statement.
static int	which(java.util.Hashtable hash, java.lang.String projects, java.lang.String options) Which - get all info.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SEPARATOR

public static final java.lang.String SEPARATOR

Generic ';' separator for various items.

See Also:

Constant Field Values

DEFAULT_PROJECTS

public static final java.lang.String DEFAULT_PROJECTS

Default set of projects to use if none provided.

See Also:

Constant Field Values

optionsBuf

protected java.lang.StringBuffer optionsBuf

optionsBuf.

projectsBuf

protected java.lang.StringBuffer projectsBuf

projectsBuf.

outWriter

protected java.io.PrintWriter outWriter

outWriter.

Constructor Detail

Which

public Which()

Method Detail

main

public static void main(java.lang.String[] args)

Command line runnability.

Parameters:

args - command line args

doMain

public void doMain(java.lang.String[] args)

Instance worker method to handle main().

Parameters:

args - command line args

which

public static int which(java.util.Hashtable hash,
                        java.lang.String projects,
                        java.lang.String options)

Which - get all info. Worker method called from doMain or suitable for calling from other programs.

Parameters:

hash - to put information in

projects - to get information about

options - to apply like strict or verbose

Returns:

status information from WhichConstant

getGeneralInfo

public static void getGeneralInfo(java.util.Hashtable hash,
                                  java.lang.String options)

Grab a couple of generally useful items, like classpath, java version, version of this file, etc..

Parameters:

hash - to put information in

getProjectsInfo

public static int getProjectsInfo(java.util.Hashtable hash,
                                  java.lang.String projects,
                                  java.lang.String options)

Get information from various project's WhichProject impls.

Each project's info is put into a subhash. Note: if projects is null, we use DEFAULT_PROJECTS.

Parameters:

hash - to put information in

projects - to get information about

options - to apply like strict or verbose

Returns:

status information from WhichConstant

reportProjectsInfo

public void reportProjectsInfo(java.util.Hashtable hash,
                               java.lang.String options,
                               int status,
                               java.io.PrintWriter out)

Print information from which() into the PrintWriter.

Simplistic implementation to report to a writer.

Parameters:

hash - to get info from (may have subhashtables)

options - to apply like strict or verbose

status - from finding version info

out - PrintWriter to send Properties.list()-like output to

reportHashtable

protected void reportHashtable(java.util.Hashtable hash,
                               java.lang.String name,
                               java.io.PrintWriter out)

Print information from a hashtable into the PrintWriter.

Provides a pre-order traversal where the parent hash has it's output dumped before recursing to any child sub hashes. Sorta looks like Properties.list() output.

Parameters:

hash - to get info from (may have subhashtables)

name - to print as header for this hash

out - PrintWriter to send Properties.list()-like output to

usage

protected java.lang.String usage()

Return our usage statement.

Returns:

String of our usage

parseArgs

protected boolean parseArgs(java.lang.String[] args)

Parse commandline args, return false if help asked for.

Parameters:

args - array of commandline args

Returns:

true if OK, false if error/usage/help needed

getVersion

public static java.lang.String getVersion()

Get simple version info about org.apache.env.Which and related classes.

Returns:

String of our file version