org.junit.platform.commons.util

Class PackageUtils

java.lang.Object

org.junit.platform.commons.util.PackageUtils

@API(status=INTERNAL,
     since="1.0")
public final class PackageUtils
extends Object

Collection of utilities for working with packages.

DISCLAIMER

These utilities are intended solely for usage within the JUnit framework itself. Any usage by external parties is not supported. Use at your own risk!

Since:

1.0

Method Summary

Modifier and Type	Method and Description
static void	assertPackageNameIsValid(String packageName) Assert that the supplied package name is valid in terms of Java syntax.
static Optional<String>	getAttribute(Class<?> type, Function<Package,String> function) Get the package attribute for the supplied type using the supplied function.
static Optional<String>	getAttribute(Class<?> type, String name) Get the value of the specified attribute name, specified as a string, or an empty Optional if the attribute was not found.

Methods inherited from class java.lang.Object

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

Method Detail

assertPackageNameIsValid

public static void assertPackageNameIsValid(String packageName)

Assert that the supplied package name is valid in terms of Java syntax.

Note: this method does not actually verify if the named package exists in the classpath.

The default package is represented by an empty string ("").

Parameters:

packageName - the package name to validate

Throws:

PreconditionViolationException - if the supplied package name is null, contains only whitespace, or contains parts that are not valid in terms of Java syntax (e.g., containing keywords such as void, import, etc.)

See Also:

SourceVersion.isName(CharSequence)

getAttribute

public static Optional<String> getAttribute(Class<?> type,
                                            Function<Package,String> function)

Get the package attribute for the supplied type using the supplied function.

This method only returns a non-empty Optional value holder if the class loader for the supplied type created a Package object and the supplied function does not return null when applied.

Parameters:

type - the type to get the package attribute for

function - a function that computes the package attribute value (e.g., Package::getImplementationTitle); never null

Returns:

an Optional containing the attribute value; never null but potentially empty

Throws:

PreconditionViolationException - if the supplied type or function is null

See Also:

Class.getPackage(), Package.getImplementationTitle(), Package.getImplementationVersion()

getAttribute

public static Optional<String> getAttribute(Class<?> type,
                                            String name)

Get the value of the specified attribute name, specified as a string, or an empty Optional if the attribute was not found. The attribute name is case-insensitive.

This method also returns an empty Optional value holder if any exception is caught while loading the manifest file via the JAR file of the specified type.

Parameters:

type - the type to get the attribute for

name - the attribute name as a string

Returns:

an Optional containing the attribute value; never null but potentially empty

Throws:

PreconditionViolationException - if the supplied type is null or the specified name is blank

See Also:

Manifest.getMainAttributes()