net.sf.jguiraffe.locators

Class ClassPathLocator

java.lang.Object

net.sf.jguiraffe.locators.AbstractLocator

net.sf.jguiraffe.locators.ClassPathLocator

All Implemented Interfaces:

Locator

public final class ClassPathLocator
extends AbstractLocator

A specific Locator implementation that can obtain resources from the class path.

This class is initialized with a resource name. The getURL() method tries to find this resource from the class path (using the LocatorUtils class. No caching is performed; each invocation of getURL() will look up the resource. Because a lookup might depend on the context class loader, multiple invocations of getURL() may yield different results. In addition, it is possible to specify the class loader to be used for resource lookup.

Instances of this class are created using the getInstance() factory method. They are immutable and thus can be shared between multiple threads.

Version:

$Id: ClassPathLocator.java 211 2012-07-10 19:49:13Z oheger $

Author:

Oliver Heger

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) Compares this object with another one.
ClassLoader	getClassLoader() Returns the default class loader used by this locator when looking up the resource name.
static ClassPathLocator	getInstance(String resourceName) Returns a ClassPathLocator instance for the specified resource name.
static ClassPathLocator	getInstance(String resourceName, ClassLoader cl) Returns a ClassPathLocator instance which looks up the specified resource name using the given class loader.
String	getResourceName() Returns the name of the resource represented by this locator.
URL	getURL() Returns the URL for the represented resource.
int	hashCode() Returns a hash code for this object.
String	toString() Returns a string representation of this object.

Methods inherited from class net.sf.jguiraffe.locators.AbstractLocator

getFile, getInputStream

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

getResourceName

public String getResourceName()

Returns the name of the resource represented by this locator.

Returns:

the resource's name

getClassLoader

public ClassLoader getClassLoader()

Returns the default class loader used by this locator when looking up the resource name. This is the class loader passed to the getInstance() method. It may be null if no specific class loader was provided when constructing this object.

Returns:

the default class loader for resource lookup

Since:

1.2

getInstance

public static ClassPathLocator getInstance(String resourceName)

Returns a ClassPathLocator instance for the specified resource name.

Parameters:

resourceName - the name of the resource (must not be null)

Returns:

the instance with this resource name

Throws:

IllegalArgumentException - if the resource name is null

getInstance

public static ClassPathLocator getInstance(String resourceName,
                                           ClassLoader cl)

Returns a ClassPathLocator instance which looks up the specified resource name using the given class loader. If a ClassLoader reference is provided, this class loader is tried first when resolving the resource name. Otherwise, the default order of class loaders is used as implemented in LocatorUtils.

Parameters:

resourceName - the name of the resource (must not be null)

cl - an optional class loader to be used for resource lookup

Returns:

the instance with this resource name

Throws:

IllegalArgumentException - if the resource name is null

Since:

1.2

getURL

public URL getURL()

Returns the URL for the represented resource. This implementation uses the LocatorUtils.locateResource(String, ClassLoader) method to find the resource on the class path. If this fails, an exception is thrown.

Returns:

the URL to the resource

Throws:

LocatorException - if the resource URL cannot be obtained

equals

public boolean equals(Object obj)

Compares this object with another one. Two instances of this class are equal if and only if they refer to the same resource name and use the same default class loader.

Overrides:

equals in class Object

Parameters:

obj - the object to be compared to

Returns:

a flag whether the objects are equal

hashCode

public int hashCode()

Returns a hash code for this object.

Overrides:

hashCode in class Object

Returns:

a hash code

toString

public String toString()

Returns a string representation of this object. This string will at least contain the resource name used by this locator.

Overrides:

toString in class Object

Returns:

a string for this object