janino 3.1.12 · org.codehaus.janino.CachingJavaSourceClassLoader

A org.codehaus.janino.JavaSourceClassLoader that uses a resource storage provided by the application to cache compiled classes and thus saving unnecessary recompilations.

The application provides access to the resource storage through a pair of a org.codehaus.commons.compiler.util.resource.ResourceFinder and a org.codehaus.commons.compiler.util.resource.ResourceCreator (see CachingJavaSourceClassLoader(ClassLoader, ResourceFinder, String, ResourceFinder, ResourceCreator).

See org.codehaus.janino.JavaSourceClassLoader#main(String[]) for an example how to use this class.

Notice: You must NOT rely on that this class stores some particular data in some particular resources through the given classFileCacheResourceFinder/Creator! These serve only as a means for the CachingJavaSourceClassLoader to persistently cache some data between invocations. In other words: If you want to compile .java files into .class files, then don't use this class but Compiler instead!

Modifier and Type	Field and Description
private final ResourceCreator	classFileCacheResourceCreator
private final ResourceFinder	classFileCacheResourceFinder
private final ResourceFinder	sourceFinder

Constructor Summary

Access Constructor and Description

Access	Constructor and Description
public	CachingJavaSourceClassLoader(ClassLoader parentClassLoader, File[] Directories to scan for source files sourcePath, String characterEncoding, File Directory to use for caching generated class files (see class description) cacheDirectory) See `CachingJavaSourceClassLoader(ClassLoader, ResourceFinder, String, ResourceFinder, ResourceCreator)`.
public	CachingJavaSourceClassLoader(ClassLoader Attempt to load classes through this one before looking for source files parentClassLoader, ResourceFinder Finds Java source for class `pkg.Cls` in resource `pkg/Cls.java` sourceFinder, String Encoding of Java source or `null` for platform default encoding characterEncoding, ResourceFinder Finds precompiled class `pkg.Cls` in resource `pkg/Cls.class` (see class description) classFileCacheResourceFinder, ResourceCreator Stores compiled class `pkg.Cls` in resource `pkg/Cls.class` (see class description) classFileCacheResourceCreator) Notice that this class is thread-safe if and only if the `classFileCacheResourceCreator` stores its data atomically, i.e. the `classFileCacheResourceFinder` sees the resource written by the `classFileCacheResourceCreator` only after the `OutputStream` is closed.

public

CachingJavaSourceClassLoader(ClassLoader parentClassLoader, File[]

Directories to scan for source files

sourcePath, String characterEncoding, File

Directory to use for caching generated class files (see class description)

cacheDirectory)

See CachingJavaSourceClassLoader(ClassLoader, ResourceFinder, String, ResourceFinder, ResourceCreator).

public

CachingJavaSourceClassLoader(ClassLoader

Attempt to load classes through this one before looking for source files

parentClassLoader, ResourceFinder

Finds Java source for class pkg.Cls in resource pkg/Cls.java

sourceFinder, String

Encoding of Java source or null for platform default encoding

characterEncoding, ResourceFinder

Finds precompiled class pkg.Cls in resource pkg/Cls.class (see class description)

classFileCacheResourceFinder, ResourceCreator

Stores compiled class pkg.Cls in resource pkg/Cls.class (see class description)

classFileCacheResourceCreator)

Notice that this class is thread-safe if and only if the classFileCacheResourceCreator stores its data atomically, i.e. the classFileCacheResourceFinder sees the resource written by the classFileCacheResourceCreator only after the OutputStream is closed.

Method Summary

Modifier and Type	Method and Description
protected Map<String, byte[]>	Returns: String name => byte[] bytecode, or `null` if no source code could be found generateBytecodes(String className) Overrides org.codehaus.janino.JavaSourceClassLoader.generateBytecodes. Overrides `JavaSourceClassLoader#generateBytecodes(String)` to implement class file caching.
private static byte[]	readResource(Resource r) Reads all bytes from the given resource.
private static void	writeResource(ResourceCreator resourceCreator, String resourceName, byte[] data) Creates a resource with the given name and store the data in it.

Inherited from org.codehaus.janino.JavaSourceClassLoader:: findClass setCompileErrorHandler setDebuggingInfo setSourceCharset setSourceFinder setSourcePath setTargetVersion setWarningHandler

Field Detail

classFileCacheResourceCreator	back to summary
private final ResourceCreator classFileCacheResourceCreator

classFileCacheResourceFinder	back to summary
private final ResourceFinder classFileCacheResourceFinder

sourceFinder	back to summary
private final ResourceFinder sourceFinder

Constructor Detail

CachingJavaSourceClassLoader back to summary

CachingJavaSourceClassLoader	back to summary
public CachingJavaSourceClassLoader(ClassLoader parentClassLoader, File[] sourcePath, String characterEncoding, File cacheDirectory) See `CachingJavaSourceClassLoader(ClassLoader, ResourceFinder, String, ResourceFinder, ResourceCreator)`. Parameters sourcePath:File[] Directories to scan for source files cacheDirectory:File Directory to use for caching generated class files (see class description)

public CachingJavaSourceClassLoader(ClassLoader parentClassLoader, File[] sourcePath, String characterEncoding, File cacheDirectory)

See CachingJavaSourceClassLoader(ClassLoader, ResourceFinder, String, ResourceFinder, ResourceCreator).

Parameters

sourcePath:File[]: Directories to scan for source files
cacheDirectory:File: Directory to use for caching generated class files (see class description)

CachingJavaSourceClassLoader back to summary

CachingJavaSourceClassLoader	back to summary
public CachingJavaSourceClassLoader(ClassLoader parentClassLoader, ResourceFinder sourceFinder, String characterEncoding, ResourceFinder classFileCacheResourceFinder, ResourceCreator classFileCacheResourceCreator) Notice that this class is thread-safe if and only if the `classFileCacheResourceCreator` stores its data atomically, i.e. the `classFileCacheResourceFinder` sees the resource written by the `classFileCacheResourceCreator` only after the `OutputStream` is closed. In order to make the caching scheme work, both the `classFileCacheResourceFinder` and the `sourceFinder` must support the `org.codehaus.commons.compiler.util.resource.Resource#lastModified()` method, so that the modification time of the source and the class files can be compared. Parameters parentClassLoader:ClassLoader Attempt to load classes through this one before looking for source files sourceFinder:ResourceFinder Finds Java source for class `pkg.Cls` in resource `pkg/Cls.java` characterEncoding:String Encoding of Java source or `null` for platform default encoding classFileCacheResourceFinder:ResourceFinder Finds precompiled class `pkg.Cls` in resource `pkg/Cls.class` (see class description) classFileCacheResourceCreator:ResourceCreator Stores compiled class `pkg.Cls` in resource `pkg/Cls.class` (see class description)

public CachingJavaSourceClassLoader(ClassLoader parentClassLoader, ResourceFinder sourceFinder, String characterEncoding, ResourceFinder classFileCacheResourceFinder, ResourceCreator classFileCacheResourceCreator)

In order to make the caching scheme work, both the classFileCacheResourceFinder and the sourceFinder must support the org.codehaus.commons.compiler.util.resource.Resource#lastModified() method, so that the modification time of the source and the class files can be compared.

Parameters

parentClassLoader:ClassLoader: Attempt to load classes through this one before looking for source files
sourceFinder:ResourceFinder: Finds Java source for class pkg.Cls in resource pkg/Cls.java
characterEncoding:String: Encoding of Java source or null for platform default encoding
classFileCacheResourceFinder:ResourceFinder: Finds precompiled class pkg.Cls in resource pkg/Cls.class (see class description)
classFileCacheResourceCreator:ResourceCreator: Stores compiled class pkg.Cls in resource pkg/Cls.class (see class description)

Method Detail

generateBytecodes back to summary

generateBytecodes	back to summary
protected Map<String, byte[]> generateBytecodes(String className) throws ClassNotFoundException Overrides org.codehaus.janino.JavaSourceClassLoader.generateBytecodes. Overrides `JavaSourceClassLoader#generateBytecodes(String)` to implement class file caching. Returns:Map<String, byte[]> String name => byte[] bytecode, or `null` if no source code could be found Annotations @Override @Nullable Exceptions ClassNotFoundException: Compilation problems or class file cache I/O problems

protected Map<String, byte[]> generateBytecodes(String className) throws ClassNotFoundException

Overrides org.codehaus.janino.JavaSourceClassLoader.generateBytecodes.

Overrides JavaSourceClassLoader#generateBytecodes(String) to implement class file caching.

Returns:Map<String, byte[]>

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

Annotations

@Override
@Nullable

Exceptions

ClassNotFoundException:: Compilation problems or class file cache I/O problems

readResource	back to summary
private static byte[] readResource(Resource r) throws IOException Reads all bytes from the given resource.

writeResource	back to summary
private static void writeResource(ResourceCreator resourceCreator, String resourceName, byte[] data) throws IOException Creates a resource with the given name and store the data in it.

public Class CachingJavaSourceClassLoader

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail