net.grinder.util

Class ClassLoaderUtilities

java.lang.Object

net.grinder.util.ClassLoaderUtilities

public class ClassLoaderUtilities
extends Object

Class loader related utilities.

Author:

Philip Aston

Constructor Summary

Constructors

Constructor and Description
ClassLoaderUtilities()

Method Summary

Methods

Modifier and Type	Method and Description
static List<String>	allResourceLines(ClassLoader classLoader, String resourceName) Find all the resources with the given path, load them, and return their contents as a list of Strings.
static <T> List<Class<? extends T>>	loadRegisteredImplementations(String resourceName, Class<T> cls) Equivalent to loadRegisteredImplementations(resourceName, cls, cls.getClassLoader()).
static <T> List<Class<? extends T>>	loadRegisteredImplementations(String resourceName, Class<T> cls, ClassLoader classLoader) Simple mechanism for dynamically specified implementations.
static List<Class<?>>	loadRegisteredImplementations(String resourceName, ClassLoader classLoader) Equivalent to loadRegisteredImplementations(resourceName, Object.class, classLoader).

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassLoaderUtilities

public ClassLoaderUtilities()

Method Detail

allResourceLines

public static List<String> allResourceLines(ClassLoader classLoader,
                            String resourceName)
                                     throws IOException

Find all the resources with the given path, load them, and return their contents as a list of Strings.

Property file style comments can be added using "#".

Lines are processed as follows:

• Comments are removed from each line.
• Leading and trailing white space is removed from each line.
• Blank lines are discarded.

Parameters:

classLoader - Starting class loader to search. The parent class loaders will be searched first - see ClassLoader.getResources(java.lang.String).

resourceName - The name of the resources. Multiple resources may have the same name if they are loaded from different class loaders.

Returns:

The contents of the resources, line by line.

Throws:

IOException - If there was a problem parsing the resources.

loadRegisteredImplementations

public static List<Class<?>> loadRegisteredImplementations(String resourceName,
                                           ClassLoader classLoader)
                                                    throws EngineException

Equivalent to loadRegisteredImplementations(resourceName, Object.class, classLoader).

Parameters:

resourceName - The name of the resources to find.

classLoader - Classloader to use to load implementations.

Returns:

The implementation classes.

Throws:

EngineException - If a class could not be loaded.

See Also:

loadRegisteredImplementations(String, Class, ClassLoader)

loadRegisteredImplementations

public static <T> List<Class<? extends T>> loadRegisteredImplementations(String resourceName,
                                                         Class<T> cls)
                                                              throws EngineException

Equivalent to loadRegisteredImplementations(resourceName, cls, cls.getClassLoader()).

Type Parameters:

T - Constrains type of cls.

Parameters:

resourceName - The name of the resources to find.

cls - Implementation classes must be assignable to this class.

Returns:

The implementation classes.

Throws:

EngineException - If a class could not be loaded.

See Also:

loadRegisteredImplementations(String, Class, ClassLoader)

loadRegisteredImplementations

public static <T> List<Class<? extends T>> loadRegisteredImplementations(String resourceName,
                                                         Class<T> cls,
                                                         ClassLoader classLoader)
                                                              throws EngineException

Simple mechanism for dynamically specified implementations.

The classpath is searched for all resources called resourceName. Matching resources are then parsed with allResourceLines(java.lang.ClassLoader, java.lang.String) to obtain a list of implementation class names. These classes are dynamically loaded, and returned.

Type Parameters:

T - Constrains type of cls.

Parameters:

resourceName - The name of the resources to find.

cls - Implementation classes must be assignable to this class.

classLoader - Classloader to use to load implementations.

Returns:

The implementation classes. The order of the classes depends on the classpath and the order of entries in individual resource files. We maintain the order because the caller might want to load more fundamental implementations first.

Throws:

EngineException - If a class could not be loaded.