Class ResourceUtils
- java.lang.Object
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- org.apache.commons.discovery.tools.ResourceUtils
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public class ResourceUtils extends java.lang.Object
Mechanisms to locate and load a class. The load methods locate a class only. The find methods locate a class and verify that the class implements an given interface or extends a given class.- Author:
- Richard A. Sitze, Craig R. McClanahan, Costin Manolache
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Constructor Summary
Constructors Constructor Description ResourceUtils()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static java.lang.String
getPackageName(java.lang.Class clazz)
Get package name.static Resource
getResource(java.lang.Class spi, java.lang.String resourceName, ClassLoaders loaders)
Load the resourceresourceName
.static java.util.Properties
loadProperties(java.lang.Class spi, java.lang.String propertiesFileName, ClassLoaders classLoaders)
Load named property file, optionally qualifed by spi's package name as per Class.getResource.
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Method Detail
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getPackageName
public static java.lang.String getPackageName(java.lang.Class clazz)
Get package name. Not all class loaders 'keep' package information, in which case Class.getPackage() returns null. This means that calling Class.getPackage().getName() is unreliable at best.
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getResource
public static Resource getResource(java.lang.Class spi, java.lang.String resourceName, ClassLoaders loaders) throws DiscoveryException
Load the resourceresourceName
. Try each classloader in succession, until first succeeds, or all fail. If all fail andresouceName
is not absolute (doesn't start with '/' character), then retry withpackageName/resourceName
after changing all '.' to '/'.- Parameters:
resourceName
- The name of the resource to load.- Throws:
DiscoveryException
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loadProperties
public static java.util.Properties loadProperties(java.lang.Class spi, java.lang.String propertiesFileName, ClassLoaders classLoaders) throws DiscoveryException
Load named property file, optionally qualifed by spi's package name as per Class.getResource. A property file is loaded using the following sequence of class loaders:- Thread Context Class Loader
- DiscoverSingleton's Caller's Class Loader
- SPI's Class Loader
- DiscoverSingleton's (this class) Class Loader
- System Class Loader
- Parameters:
propertiesFileName
- The property file name.- Returns:
- Instance of a class implementing the SPI.
- Throws:
DiscoveryException
- Thrown if the name of a class implementing the SPI cannot be found, if the class cannot be loaded and instantiated, or if the resulting class does not implement (or extend) the SPI.
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