[Java] Class GroovyClassLoader

  • groovy.lang.GroovyClassLoader

A ClassLoader which can load Groovy classes. The loaded classes are cached, classes from other classloaders should not be cached. To be able to load a script that was asked for earlier but was created later it is essential not to keep anything like a "class not found" information for that class name. This includes possible parent loaders. Classes that are not cached are always reloaded.

Nested Class Summary

Nested classes
Modifiers Name Description
static class GroovyClassLoader.ClassCollector
static class GroovyClassLoader.InnerLoader

Field Summary

Fields
Modifiers Name Description
protected Map<String, Class> classCache this cache contains the loaded classes or PARSING, if the class is currently parsed
protected Map<String, Class> sourceCache This cache contains mappings of file name to class.

Properties Summary

Properties
Type Name and description
GroovyResourceLoader resourceLoader
Boolean shouldRecompile

Constructor Summary

Constructors
Constructor and description
GroovyClassLoader ()
creates a GroovyClassLoader using the current Thread's context Class loader as parent.
GroovyClassLoader (ClassLoader loader)
creates a GroovyClassLoader using the given ClassLoader as parent
GroovyClassLoader (GroovyClassLoader parent)
creates a GroovyClassLoader using the given GroovyClassLoader as parent.
GroovyClassLoader (ClassLoader parent, CompilerConfiguration config, boolean useConfigurationClasspath)
creates a GroovyClassLoader.
GroovyClassLoader (ClassLoader loader, CompilerConfiguration config)
creates a GroovyClassLoader using the given ClassLoader as parent.

Methods Summary

Methods
Type Params Return Type Name and description
void addClasspath(String path)
adds a classpath to this classloader.
void addURL(URL url)
adds a URL to the classloader.
void clearCache()
Removes all classes from the class cache.
void close()
Closes this GroovyClassLoader and clears any caches it maintains.
protected ClassCollector createCollector(CompilationUnit unit, SourceUnit su)
creates a ClassCollector for a new compilation.
protected CompilationUnit createCompilationUnit(CompilerConfiguration config, CodeSource source)
creates a new CompilationUnit.
Class defineClass(ClassNode classNode, String file, String newCodeBase)
Loads the given class node returning the implementation Class.
Class defineClass(String name, byte[] b)
open up the super class define that takes raw bytes
String generateScriptName()
protected Class getClassCacheEntry(String name)
gets a class from the class cache.
protected String[] getClassPath()
gets the currently used classpath.
Class[] getLoadedClasses()
protected PermissionCollection getPermissions(CodeSource codeSource)
GroovyResourceLoader getResourceLoader()
protected long getTimeStamp(Class cls)
gets the time stamp of a given class.
boolean hasCompatibleConfiguration(CompilerConfiguration config)
Check if this class loader has compatible CompilerConfiguration with the provided one.
protected boolean isRecompilable(Class cls)
Indicates if a class is recompilable.
Boolean isShouldRecompile()
gets the currently set recompilation mode. null means, the compiler configuration is used.
protected boolean isSourceNewer(URL source, Class cls)
Decides if the given source is newer than a class.
Class loadClass(String name, boolean lookupScriptFiles, boolean preferClassOverScript)
loads a class from a file or a parent classloader.
Class loadClass(String name, boolean lookupScriptFiles, boolean preferClassOverScript, boolean resolve)
loads a class from a file or a parent classloader.
Class<?> loadClass(String name)
protected Class loadClass(String name, boolean resolve)
Implemented here to check package access prior to returning an already loaded class.
Class parseClass(File file)
Parses the given file into a Java class capable of being run
Class parseClass(String text, String fileName)
Parses the given text into a Java class capable of being run
Class parseClass(String text)
Parses the given text into a Java class capable of being run
Class parseClass(Reader reader, String fileName)
Class parseClass(InputStream in, String fileName)
deprecated:
Prefer using methods taking a Reader rather than an InputStream to avoid wrong encoding issues.
Class parseClass(GroovyCodeSource codeSource)
Class parseClass(GroovyCodeSource codeSource, boolean shouldCacheSource)
Parses the given code source into a Java class.
protected Class recompile(URL source, String className, Class oldClass)
(Re)Compiles the given source.
protected void removeClassCacheEntry(String name)
removes a class from the class cache.
protected void setClassCacheEntry(Class cls)
sets an entry in the class cache.
void setResourceLoader(GroovyResourceLoader resourceLoader)
void setShouldRecompile(Boolean mode)
sets if the recompilation should be enable.

Inherited Methods Summary

Inherited Methods
Methods inherited from class Name
class URLClassLoader getResourceAsStream, newInstance, newInstance, findResource, findResources, close, getURLs, loadClass, getSystemClassLoader, getResource, getSystemResource, getSystemResourceAsStream, clearAssertionStatus, getParent, getResources, getSystemResources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll

Field Detail

protected final Map<String, Class> classCache

this cache contains the loaded classes or PARSING, if the class is currently parsed

protected final Map<String, Class> sourceCache

This cache contains mappings of file name to class. It is used to bypass compilation.

Property Detail

GroovyResourceLoader resourceLoader

Boolean shouldRecompile

Constructor Detail

public GroovyClassLoader()

creates a GroovyClassLoader using the current Thread's context Class loader as parent.

public GroovyClassLoader(ClassLoader loader)

creates a GroovyClassLoader using the given ClassLoader as parent

public GroovyClassLoader(GroovyClassLoader parent)

creates a GroovyClassLoader using the given GroovyClassLoader as parent. This loader will get the parent's CompilerConfiguration

public GroovyClassLoader(ClassLoader parent, CompilerConfiguration config, boolean useConfigurationClasspath)

creates a GroovyClassLoader.

Parameters:
parent - the parent class loader
config - the compiler configuration
useConfigurationClasspath - determines if the configurations classpath should be added

public GroovyClassLoader(ClassLoader loader, CompilerConfiguration config)

creates a GroovyClassLoader using the given ClassLoader as parent.

Method Detail

public void addClasspath(String path)

adds a classpath to this classloader.

Parameters:
path - is a jar file or a directory.
See Also:
addURL(URL)

public void addURL(URL url)

adds a URL to the classloader.

Parameters:
url - the new classpath element

public void clearCache()

Removes all classes from the class cache.

In addition to internal caches this method also clears any previously set MetaClass information for the given set of classes being removed.

See Also:
getClassCacheEntry(String)
setClassCacheEntry(Class)
removeClassCacheEntry(String)

@Override public void close()

Closes this GroovyClassLoader and clears any caches it maintains.

No use should be made of this instance after this method is invoked. Any classes that are already loaded are still accessible.

throws:
IOException
See Also:
URLClassLoader.close
clearCache()
Since:
2.5.0

protected ClassCollector createCollector(CompilationUnit unit, SourceUnit su)

creates a ClassCollector for a new compilation.

Parameters:
unit - the compilationUnit
su - the SourceUnit
Returns:
the ClassCollector

protected CompilationUnit createCompilationUnit(CompilerConfiguration config, CodeSource source)

creates a new CompilationUnit. If you want to add additional phase operations to the CompilationUnit (for example to inject additional methods, variables, fields), then you should overwrite this method.

Parameters:
config - the compiler configuration, usually the same as for this class loader
source - the source containing the initial file to compile, more files may follow during compilation
Returns:
the CompilationUnit

public Class defineClass(ClassNode classNode, String file, String newCodeBase)

Loads the given class node returning the implementation Class.

WARNING: this compilation is not synchronized

Parameters:
classNode
Returns:
a class

public Class defineClass(String name, byte[] b)

open up the super class define that takes raw bytes

public String generateScriptName()

protected Class getClassCacheEntry(String name)

gets a class from the class cache. This cache contains only classes loaded through this class loader or an InnerLoader instance. If no class is stored for a specific name, then the method should return null.

Parameters:
name - of the class
Returns:
the class stored for the given name
See Also:
removeClassCacheEntry(String)
setClassCacheEntry(Class)
clearCache()

protected String[] getClassPath()

gets the currently used classpath.

Returns:
a String[] containing the file information of the urls
See Also:
getURLs()

public Class[] getLoadedClasses()

Returns all Groovy classes loaded by this class loader.

Returns:
all classes loaded by this class loader

protected PermissionCollection getPermissions(CodeSource codeSource)

public GroovyResourceLoader getResourceLoader()

protected long getTimeStamp(Class cls)

gets the time stamp of a given class. For groovy generated classes this usually means to return the value of the static field __timeStamp. If the parameter doesn't have such a field, then Long.MAX_VALUE is returned

Parameters:
cls - the class
Returns:
the time stamp

public boolean hasCompatibleConfiguration(CompilerConfiguration config)

Check if this class loader has compatible CompilerConfiguration with the provided one.

Parameters:
config - the compiler configuration to test for compatibility
Returns:
true if the provided config is exactly the same instance of CompilerConfiguration as this loader has

protected boolean isRecompilable(Class cls)

Indicates if a class is recompilable. Recompilable means, that the classloader will try to locate a groovy source file for this class and then compile it again, adding the resulting class as entry to the cache. Giving null as class is like a recompilation, so the method should always return true here. Only classes that are implementing GroovyObject are compilable and only if the timestamp in the class is lower than Long.MAX_VALUE.

NOTE: First the parent loaders will be asked and only if they don't return a class the recompilation will happen. Recompilation also only happen if the source file is newer.

Parameters:
cls - the class to be tested. If null the method should return true
Returns:
true if the class should be compiled again
See Also:
isSourceNewer(URL, Class)

public Boolean isShouldRecompile()

gets the currently set recompilation mode. null means, the compiler configuration is used. False means no recompilation and true means that recompilation will be done if needed.

Returns:
the recompilation mode

protected boolean isSourceNewer(URL source, Class cls)

Decides if the given source is newer than a class.

throws:
IOException if it is not possible to open an connection for the given source
Parameters:
source - the source we may want to compile
cls - the former class
Returns:
true if the source is newer, false else
See Also:
getTimeStamp(Class)

public Class loadClass(String name, boolean lookupScriptFiles, boolean preferClassOverScript)

loads a class from a file or a parent classloader. This method does call loadClass(String, boolean, boolean, boolean) with the last parameter set to false.

throws:
CompilationFailedException if compilation was not successful

public Class loadClass(String name, boolean lookupScriptFiles, boolean preferClassOverScript, boolean resolve)

loads a class from a file or a parent classloader.

throws:
ClassNotFoundException if the class could not be found
throws:
CompilationFailedException if the source file could not be compiled
Parameters:
name - of the class to be loaded
lookupScriptFiles - if false no lookup at files is done at all
preferClassOverScript - if true the file lookup is only done if there is no class
resolve - see ClassLoader.loadClass
Returns:
the class found or the class created from a file lookup

@Override public Class<?> loadClass(String name)

protected Class loadClass(String name, boolean resolve)

Implemented here to check package access prior to returning an already loaded class.

throws:
CompilationFailedException if the compilation failed
throws:
ClassNotFoundException if the class was not found
See Also:
ClassLoader.loadClass

public Class parseClass(File file)

Parses the given file into a Java class capable of being run

Parameters:
file - the file name to parse
Returns:
the main class defined in the given script

public Class parseClass(String text, String fileName)

Parses the given text into a Java class capable of being run

Parameters:
text - the text of the script/class to parse
fileName - the file name to use as the name of the class
Returns:
the main class defined in the given script

public Class parseClass(String text)

Parses the given text into a Java class capable of being run

Parameters:
text - the text of the script/class to parse
Returns:
the main class defined in the given script

public Class parseClass(Reader reader, String fileName)

@Deprecated public Class parseClass(InputStream in, String fileName)

deprecated:
Prefer using methods taking a Reader rather than an InputStream to avoid wrong encoding issues. Use parseClass instead

public Class parseClass(GroovyCodeSource codeSource)

public Class parseClass(GroovyCodeSource codeSource, boolean shouldCacheSource)

Parses the given code source into a Java class. If there is a class file for the given code source, then no parsing is done, instead the cached class is returned.

Parameters:
shouldCacheSource - if true then the generated class will be stored in the source cache
Returns:
the main class defined in the given script

protected Class recompile(URL source, String className, Class oldClass)

(Re)Compiles the given source. This method starts the compilation of a given source, if the source has changed since the class was created. For this isSourceNewer is called.

throws:
CompilationFailedException if the compilation failed
throws:
IOException if the source is not readable
Parameters:
source - the source pointer for the compilation
className - the name of the class to be generated
oldClass - a possible former class
Returns:
the old class if the source wasn't new enough, the new class else
See Also:
isSourceNewer(URL, Class)

protected void removeClassCacheEntry(String name)

removes a class from the class cache.

Parameters:
name - of the class
See Also:
getClassCacheEntry(String)
setClassCacheEntry(Class)
clearCache()

protected void setClassCacheEntry(Class cls)

sets an entry in the class cache.

Parameters:
cls - the class
See Also:
removeClassCacheEntry(String)
getClassCacheEntry(String)
clearCache()

public void setResourceLoader(GroovyResourceLoader resourceLoader)

public void setShouldRecompile(Boolean mode)

sets if the recompilation should be enable. There are 3 possible values for this. Any value different than null overrides the value from the compiler configuration. true means to recompile if needed false means to never recompile.

Parameters:
mode - the recompilation mode
See Also:
CompilerConfiguration

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Licensed under the Apache license.
https://docs.groovy-lang.org/2.5.14/html/gapi/groovy/lang/GroovyClassLoader.html