imagingbook.lib.util

Class ResourceUtils

java.lang.Object

imagingbook.lib.util.ResourceUtils

public class ResourceUtils
extends Object

This class defines static methods for accessing resources. What makes things somewhat complex is the requirement that we want to retrieve resources located in the file system or contained inside a JAR file. A typical URI for a JAR-embedded file: "jar:file:/C:/PROJEC~2/parent/IM1D84~1/ImageJ/jars/jarWithResources.jar!/jarWithResouces/resources/clown.jpg"

Version:

2016/06/04

Constructor Summary

Constructors

Constructor and Description
ResourceUtils()

Method Summary

Modifier and Type	Method and Description
static Path	getResourcePath(Class<?> clazz, String relPath) Find the path to a resource relative to the location of class c.
static URI	getResourceUri(Class<?> clazz, String relPath) Finds the URI for a resource relative to a specified class.
static boolean	isInsideJar(Class<?> clazz) Determines if the specified class was loaded from a JAR file or a .class file in the file system.
static Path[]	listResources(Class<?> clazz, String relPath) Use this method to obtain the paths to all files in a directory located relative to the specified class.
static Path[]	listResources(Path path) Method to obtain the paths to all files in a directory specified by a path.
static Path[]	listResources(URI uri)
static ij.ImagePlus	openImageFromResource(Class<?> clazz, String resDir, String resName) Opens an image from the specified resource.
static Path	uriToPath(URI uri) Converts an URI to a Path for locations that are either in the file system or inside a JAR file.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceUtils

public ResourceUtils()

Method Detail

isInsideJar

public static boolean isInsideJar(Class<?> clazz)

Determines if the specified class was loaded from a JAR file or a .class file in the file system.

Parameters:

clazz - the class

Returns:

true if contained in a JAR file, false otherwise

getResourceUri

public static URI getResourceUri(Class<?> clazz,
                                 String relPath)

Finds the URI for a resource relative to a specified class. The resource may be located in the file system or inside a JAR file.

Parameters:

clazz - the anchor class

relPath - the resource path relative to the anchor class

Returns:

the URI or null if the resource was not found

getResourcePath

public static Path getResourcePath(Class<?> clazz,
                                   String relPath)

Find the path to a resource relative to the location of class c. Example: Assume class C was loaded from file someLocation/C.class and there is a subfolder someLocation/resources/ that contains an image 'lenna.jpg'. Then the absolute path to this image is obtained by String path = getResourcePath(C.class, "resources/lenna.jpg"); 2016-06-03: modified to return proper path to resource inside a JAR file.

Parameters:

clazz - anchor class

relPath - the path of the resource to be found (relative to the location of the anchor class)

Returns:

the path to the specified resource

uriToPath

public static Path uriToPath(URI uri)

Converts an URI to a Path for locations that are either in the file system or inside a JAR file.

Parameters:

uri - the specified location

Returns:

the associated path

listResources

public static Path[] listResources(URI uri)

listResources

public static Path[] listResources(Path path)

Method to obtain the paths to all files in a directory specified by a path. This should work in an ordinary file system as well as a (possibly nested) JAR file.

Parameters:

path - path to a directory (may be contained in a JAR file)

Returns:

a sequence of paths or null if the specified path is not a directory

listResources

public static Path[] listResources(Class<?> clazz,
                                   String relPath)

Use this method to obtain the paths to all files in a directory located relative to the specified class. This should work in an ordinary file system as well as a (possibly nested) JAR file.

Parameters:

clazz - class whose source location specifies the root

relPath - path relative to the root

Returns:

a sequence of paths or null if the specified path is not a directory

openImageFromResource

public static ij.ImagePlus openImageFromResource(Class<?> clazz,
                                                 String resDir,
                                                 String resName)

Opens an image from the specified resource. If the resource is contained inside a JAR file, it is first extracted to a temporary file and subsequently opened with ImageJ's Opener class.

Parameters:

clazz - the anchor class

resDir - the directory relative to the anchor class

resName - the (file) name of the image resource

Returns:

the opened image or null if not successful.