Package eu.simuline.testhelpers

Class TestCaseClassLoader

java.lang.Object

java.lang.ClassLoader

eu.simuline.testhelpers.TestCaseClassLoader

public final class TestCaseClassLoader
extends ClassLoader

A custom class loader which allows to reload classes for each test run. The class loader can be configured with a list of package paths that should be excluded from loading. The loading of these packages is delegated to the system class loader. They will be shared across test runs.

The list of excluded package paths is either hardcoded in defaultExclusions, specified as property with key PROP_KEY_NO_CLS_RELOAD. in a properties file EXCLUDED_FILE that is located in the same place as the TestCaseClassLoader class.

Known limitation:

• the TestCaseClassLoader cannot load classes from jar files.
• service providers must be excluded from reloading.

Version:

1.0

Author:

Ernst Reissner

Field Summary

Fields

Modifier and Type	Field	Description
private String[]	defaultExclusions	Default excluded paths.
private List<String>	excluded	Holds the excluded paths.
(package private) static String	EXCLUDED_FILE	Name of excluded properties file.
private JavaPath	jPath	The scanned class path.
private static int	LEN_CLS_STREAM	The initial length of a stream to read class files from.
private static String	PROP_KEY_NO_CLS_RELOAD	Key of system property containing a ":"-separated list of packages or classes to be excluded from reloading.

Constructor Summary

Constructors

Modifier	Constructor	Description
	TestCaseClassLoader()	Constructs a TestCaseLoader.
private	TestCaseClassLoader(String classPath)	Constructs a TestCaseLoader.

Method Summary

Modifier and Type	Method	Description
(package private) Class<?>	defineClass(String name)
URL	getResource(String name)
InputStream	getResourceAsStream(String name)
private boolean	isExcluded(String name)	Returns whether the name with the given name is excluded from being loaded.
Class<?>	loadClass(String name, boolean resolve)
private byte[]	lookupClassData(String className)
private void	readExcludedPackages()	Initializes excluded using defaultExclusions, PROP_KEY_NO_CLS_RELOAD and EXCLUDED_FILE.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Detail

PROP_KEY_NO_CLS_RELOAD

private static final String PROP_KEY_NO_CLS_RELOAD

Key of system property containing a ":"-separated list of packages or classes to be excluded from reloading. Each is read into excluded.

See Also:

Constant Field Values

EXCLUDED_FILE

static final String EXCLUDED_FILE

Name of excluded properties file. This shall be located in the same folder as this class loader. The property keys shall have the form exlude.xxx and are read in excluded.

See Also:

Constant Field Values

LEN_CLS_STREAM

private static final int LEN_CLS_STREAM

The initial length of a stream to read class files from.

See Also:

Constant Field Values

jPath

private JavaPath jPath

The scanned class path.

excluded

private List<String> excluded

Holds the excluded paths. This is initialized by readExcludedPackages() and used by isExcluded(java.lang.String).

defaultExclusions

private final String[] defaultExclusions

Default excluded paths.

See Also:

isExcluded(java.lang.String)

Constructor Detail

TestCaseClassLoader

public TestCaseClassLoader()

Constructs a TestCaseLoader. It scans the class path and the excluded package paths.

TestCaseClassLoader

private TestCaseClassLoader(String classPath)

Constructs a TestCaseLoader. It scans the class path and the excluded package paths.

Parameters:

classPath - the classpath.

Method Detail

getResource

public URL getResource(String name)

Overrides:

getResource in class ClassLoader

getResourceAsStream

public InputStream getResourceAsStream(String name)

Overrides:

getResourceAsStream in class ClassLoader

isExcluded

private boolean isExcluded(String name)

Returns whether the name with the given name is excluded from being loaded.

Parameters:

name - the fully qualified name of a class as a String.

Returns:

a boolean which shows whether name starts with one of the prefixes given by excluded. In this case the corresponding class is not loaded.

defineClass

Class<?> defineClass(String name)
              throws ClassNotFoundException

Throws:

ClassNotFoundException

loadClass

public Class<?> loadClass(String name,
                          boolean resolve)
                   throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

lookupClassData

private byte[] lookupClassData(String className)
                        throws ClassNotFoundException

Throws:

ClassNotFoundException

readExcludedPackages

private void readExcludedPackages()

Initializes excluded using defaultExclusions, PROP_KEY_NO_CLS_RELOAD and EXCLUDED_FILE.

1. First the entries of defaultExclusions are added to excluded.
2. Then PROP_KEY_NO_CLS_RELOAD is interpreted as a ":"-seprated list of entries each of which is added to excluded.
3. Finally, EXCLUDED_FILE is interpreted as filename and the file is interpreted as Properties File with property keys starting with excluded.; all the other properties are ignored. The values are trimmed and a trailing * is removed if present. If the remaining path is nontrivial, it is added to excluded.