org.lsst.ccs.utilities.jars
Class CommonResources

java.lang.Object
  org.lsst.ccs.utilities.jars.CommonResources

public class CommonResources
extends Object

This class deals with "common resources": that is resources that are not linked to a specific package (such resources are often queried using an initial slash when querying a resource through the Class resource methods such as getResource : getResource("/global.properties")).

Beware: in the codeusing this class these resource names should not start with a slash (same protocol as with the ClassLoader resource methods.

The general idea is that when dealing with multiple jars there may be many "common resources" with the same name.
So:

• the getURLsFrom method will return all the URL of this resource known by a ClassLoader (chances are that there may be many of these)
• the getURLsFor method will return the resource linked to a specific object. So if there are many resources with the same name this will pick up only the one that is in the jar of the current class. (chances are that there may be only one such resource: but this is not 100% sure if different versions of the same class are referenced in different jars! -an unlikely occurence-)

Other utilities methods:

• getPropertiesFrom(URL) loads a property from a common resource
• getResourceContainer gives the name of the jar that contains a resource

Author:

bamade

Field Summary

static URL[]

URL_ARRAY_MODEL

Constructor Summary

CommonResources()

Method Summary

static String[]	getClassURLNamesFor(Object obj) get the names of places where a Class lies in the classPath
static Manifest	getManifestFor(Object obj) returns a Manifest for an object
static Properties	getPropertiesFrom(URL url) fills a Property Object from an URL the references a file in ".properties" format
static String	getResourceContainer(URL url, String commonResourceName) gets the name of a jar that contains a "common resource"
static URL[]	getURLsFor(Object obj, String commonResourceName) return the URL of a resource that lies in the same jar as a class.
static URL[]	getURLsFrom(ClassLoader loader, String commonResourceName) As "seen" from a ClassLoader the various URLs that point to resources with a given name
static URL[]	getURLsFrom(String commonResourceName) As "seen" from the context ClassLoader the various URLs that point to resources with a given name

Methods inherited from class java.lang.Object

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

Field Detail

URL_ARRAY_MODEL

public static final URL[] URL_ARRAY_MODEL

Constructor Detail

CommonResources

public CommonResources()

Method Detail

getURLsFrom

public static URL[] getURLsFrom(ClassLoader loader,
                                String commonResourceName)

As "seen" from a ClassLoader the various URLs that point to resources with a given name

Parameters:

loader - a current ClassLoader

commonResourceName - name of resource (without initial slash!)

Returns:

an Array of URL that point to resources with that name

getURLsFrom

public static URL[] getURLsFrom(String commonResourceName)

As "seen" from the context ClassLoader the various URLs that point to resources with a given name

Parameters:

commonResourceName - name of resource (without initial slash!)

Returns:

an Array of URL that point to resources with that name

getURLsFor

public static URL[] getURLsFor(Object obj,
                               String commonResourceName)

return the URL of a resource that lies in the same jar as a class.

Parameters:

obj - any instance of a Class object if no instance is at hand

commonResourceName - name of resource (without initial slash!)

Returns:

an Array (with normally only one element)

getClassURLNamesFor

public static String[] getClassURLNamesFor(Object obj)

get the names of places where a Class lies in the classPath

Parameters:

obj - any object or Class

Returns:

mostly an array of size one

getPropertiesFrom

public static Properties getPropertiesFrom(URL url)

fills a Property Object from an URL the references a file in ".properties" format

Parameters:

url -

Returns:

a Properties object that may be empty if URL incorrect (or read error of the resource)

getResourceContainer

public static String getResourceContainer(URL url,
                                          String commonResourceName)

gets the name of a jar that contains a "common resource"

Parameters:

url -

commonResourceName - name of resource (without initial slash!)

Returns:

the name of a jar that "contains" the object referenced by the URL (can also be a directory)

getManifestFor

public static Manifest getManifestFor(Object obj)

returns a Manifest for an object

Parameters:

obj - an object instance or a Class

Returns:

a Manifest or null if not found