Class JavaSourceClassLoader

java.lang.Object

java.lang.ClassLoader

org.codehaus.commons.compiler.AbstractJavaSourceClassLoader

org.codehaus.janino.JavaSourceClassLoader

Direct Known Subclasses:

CachingJavaSourceClassLoader

public class JavaSourceClassLoader
extends AbstractJavaSourceClassLoader

A ClassLoader that, unlike usual ClassLoaders, does not load byte code, but reads Java source code and then scans, parses, compiles and loads it into the virtual machine.

As with any ClassLoader, it is not possible to "update" classes after they've been loaded. The way to achieve this is to give up on the JavaSourceClassLoader and create a new one.

Notice that this class loader does not support resoures in the sense of ClassLoader.getResource(String), ClassLoader.getResourceAsStream(String) nd ClassLoader.getResources(String).

See Also:

• ClassLoaders

Nested Class Summary

Nested classes/interfaces inherited from class AbstractJavaSourceClassLoader

AbstractJavaSourceClassLoader.ProtectionDomainFactory

Field Summary

Fields

Modifier and Type	Field	Description
private final Set<UnitCompiler>	compiledUnitCompilers
private boolean	debugLines
private boolean	debugSource
private boolean	debugVars
private final JavaSourceIClassLoader	iClassLoader
private final Map<String,byte[]>	precompiledClasses	This Map keeps those classes which were already compiled, but not yet defined i.e.

Fields inherited from class AbstractJavaSourceClassLoader

protectionDomainFactory

Constructor Summary

Constructors

Constructor	Description
JavaSourceClassLoader()
JavaSourceClassLoader(ClassLoader parentClassLoader)
JavaSourceClassLoader(ClassLoader parentClassLoader, File[] sourcePath, String characterEncoding)	Sets up a JavaSourceClassLoader that finds Java source code in a file that resides in either of the directories specified by the given source path.
JavaSourceClassLoader(ClassLoader parentClassLoader, ResourceFinder sourceFinder, String characterEncoding)	Constructs a JavaSourceClassLoader that finds Java source code through a given ResourceFinder.
JavaSourceClassLoader(ClassLoader parentClassLoader, JavaSourceIClassLoader iClassLoader)	Constructs a JavaSourceClassLoader that finds classes through an JavaSourceIClassLoader.

Method Summary

Modifier and Type	Method	Description
private Class<?>	defineBytecode(String className, byte[] ba)
protected Class<?>	findClass(String name)	Implementation of ClassLoader.findClass(String).
protected Map<String,byte[]>	generateBytecodes(String name)	Finds, scans, parses the right compilation unit.
void	setCompileErrorHandler(ErrorHandler compileErrorHandler)
void	setDebuggingInfo(boolean debugSource, boolean debugLines, boolean debugVars)
void	setSourceCharset(Charset charset)
void	setSourceFinder(ResourceFinder sourceFinder)
void	setSourcePath(File[] sourcePath)
void	setTargetVersion(int version)
void	setWarningHandler(WarningHandler warningHandler)

Methods inherited from class AbstractJavaSourceClassLoader

getResourceAsStream, main, setProtectionDomainFactory, setSourceFileCharacterEncoding

Methods inherited from class ClassLoader

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

Methods inherited from class Object

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

Field Details

compiledUnitCompilers

private final Set<UnitCompiler> compiledUnitCompilers

precompiledClasses

private final Map<String,byte[]> precompiledClasses

This Map keeps those classes which were already compiled, but not yet defined i.e. which were not yet passed to ClassLoader.defineClass(java.lang.String, byte[], int, int).

iClassLoader

private final JavaSourceIClassLoader iClassLoader

debugSource

private boolean debugSource

debugLines

private boolean debugLines

debugVars

private boolean debugVars

Constructor Details

JavaSourceClassLoader

public JavaSourceClassLoader()

JavaSourceClassLoader

public JavaSourceClassLoader(ClassLoader parentClassLoader)

JavaSourceClassLoader

public JavaSourceClassLoader(ClassLoader parentClassLoader,
 @Nullable
 File[] sourcePath,
 @Nullable
 String characterEncoding)

Sets up a JavaSourceClassLoader that finds Java source code in a file that resides in either of the directories specified by the given source path.

Parameters:

parentClassLoader - See ClassLoader

sourcePath - A collection of directories that are searched for Java source files in the given order

characterEncoding - The encoding of the Java source files (null for platform default encoding)

JavaSourceClassLoader

public JavaSourceClassLoader(ClassLoader parentClassLoader,
 ResourceFinder sourceFinder,
 @Nullable
 String characterEncoding)

Constructs a JavaSourceClassLoader that finds Java source code through a given ResourceFinder.

You can specify to include certain debugging information in the generated class files, which is useful if you want to debug through the generated classes (see Scanner(String, Reader)).

Parameters:

parentClassLoader - See ClassLoader

sourceFinder - Used to locate additional source files

characterEncoding - The encoding of the Java source files (null for platform default encoding)

JavaSourceClassLoader

public JavaSourceClassLoader(ClassLoader parentClassLoader,
 JavaSourceIClassLoader iClassLoader)

Constructs a JavaSourceClassLoader that finds classes through an JavaSourceIClassLoader.

Method Details

setSourcePath

public void setSourcePath(File[] sourcePath)

Specified by:

setSourcePath in class AbstractJavaSourceClassLoader

Parameters:

sourcePath - The sequence of directories to search for Java source files

setSourceFinder

public void setSourceFinder(ResourceFinder sourceFinder)

Specified by:

setSourceFinder in class AbstractJavaSourceClassLoader

Parameters:

sourceFinder - Is used when searching for Java source files

setSourceCharset

public void setSourceCharset(Charset charset)

Specified by:

setSourceCharset in class AbstractJavaSourceClassLoader

Parameters:

charset - The character set to using when reading characters from a source file

setDebuggingInfo

public void setDebuggingInfo(boolean debugSource,
 boolean debugLines,
 boolean debugVars)

Specified by:

setDebuggingInfo in class AbstractJavaSourceClassLoader

Parameters:

debugSource - Whether line number debugging information should be generated

debugLines - Whether variables debugging information should be generated

debugVars - Whether source file debugging information should be generated

setTargetVersion

public void setTargetVersion(int version)

setCompileErrorHandler

public void setCompileErrorHandler(@Nullable
 ErrorHandler compileErrorHandler)

See Also:

• UnitCompiler.setCompileErrorHandler(ErrorHandler)

setWarningHandler

public void setWarningHandler(@Nullable
 WarningHandler warningHandler)

See Also:

• Parser.setWarningHandler(WarningHandler)
• UnitCompiler.setCompileErrorHandler(ErrorHandler)

findClass

protected Class<?> findClass(@Nullable
 String name)
                      throws ClassNotFoundException

Implementation of ClassLoader.findClass(String).

Overrides:

findClass in class ClassLoader

Throws:

ClassNotFoundException

generateBytecodes

@Nullable
protected Map<String,byte[]> generateBytecodes(String name)
                                        throws ClassNotFoundException

Finds, scans, parses the right compilation unit. Compile the parsed compilation unit to bytecode. This may cause more compilation units being scanned and parsed. Continue until all compilation units are compiled.

Returns:

String name => byte[] bytecode, or null if no source code could be found

Throws:

ClassNotFoundException - on compilation problems

defineBytecode

private Class<?> defineBytecode(String className,
 byte[] ba)

Throws:

ClassFormatError

See Also:

• AbstractJavaSourceClassLoader.setProtectionDomainFactory(AbstractJavaSourceClassLoader.ProtectionDomainFactory)