org.datanucleus.enhancer.jdo

Class JDOClassEnhancer

java.lang.Object

org.datanucleus.enhancer.AbstractClassEnhancer

org.datanucleus.enhancer.jdo.JDOClassEnhancer

All Implemented Interfaces:

ClassEnhancer

public class JDOClassEnhancer
extends AbstractClassEnhancer

Class enhancer using ASM (http://asm.objectweb.org). Assumes that the version of ASM is 3.0 or above. ASM operates using a SAXParser-like "visitor-pattern". We utilise this as follows :-

• enhance : start with a ClassReader for the class to be enhanced, and create a JdoClassAdapter (attached to a ClassWriter) that will perform the modifications, and use that as a visitor for the reader so that the reader sends its events to the adapter. Within the JdoClassAdapter we also make use of a JdoMethodAdapter to update individual methods
• check : take a ClassReader, and create a JdoClassChecker that performs the checks. We then set the checker as a visitor for the reader so that the reader sends its events to the checker.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JDOClassEnhancer.MyClassVisitor Convenience class to look up the class name for a file.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	asmClassName ASM Class name for this class (replace .
protected byte[]	classBytes Bytes of the class (after enhancing).
protected String	classDescriptor Class descriptor for this class.
protected Class	cls Class that is being enhanced.
protected byte[]	inputBytes Bytes of the input class (only when enhancing generated classes with no class file).
protected String	inputResourceName Resource name of the input class (only when the class exists in a class file).
protected EnhancementNamer	namer
protected byte[]	pkClassBytes Bytes for any auto-generated PK class (if generated during enhancement).

Fields inherited from class org.datanucleus.enhancer.AbstractClassEnhancer

className, clr, cmd, fieldsToAdd, initialised, LOCALISER, metaDataMgr, methodsToAdd, options, update

Fields inherited from interface org.datanucleus.enhancer.ClassEnhancer

ASM_API_VERSION, OPTION_GENERATE_DEFAULT_CONSTRUCTOR, OPTION_GENERATE_DETACH_LISTENER, OPTION_GENERATE_PK

Constructor Summary

Constructors

Constructor and Description
JDOClassEnhancer(ClassMetaData cmd, ClassLoaderResolver clr, MetaDataManager mmgr) Constructor for an enhancer for the class.
JDOClassEnhancer(ClassMetaData cmd, ClassLoaderResolver clr, MetaDataManager mmgr, byte[] classBytes) Constructor for an enhancer to enhance a class defined by the provided bytes.

Method Summary

Methods

Modifier and Type	Method and Description
protected boolean	checkClassIsEnhanced(boolean logErrors) Convenience method to return if a class is enhanced.
boolean	enhance() Method to enhance a classes definition.
String	getASMClassName() Accessor for the ASM class name
Class	getClassBeingEnhanced() Accessor for the class being enhanced.
byte[]	getClassBytes() Accessor for the class bytes.
String	getClassDescriptor() Accessor for the class descriptor for the class being enhanced
static String	getClassNameForFileName(String filename) Convenience accessor for the class name that is stored in a particular class.
EnhancementNamer	getNamer()
byte[]	getPrimaryKeyClassBytes() Accessor for the primary-key class bytes (if generating a PK).
protected void	initialiseFieldsList() Method to initialise the list of fields to add.
protected void	initialiseMethodsList() Method to initialise the list of methods to add.
void	setNamer(EnhancementNamer namer)
boolean	validate() Validate whether the class is enhanced.

Methods inherited from class org.datanucleus.enhancer.AbstractClassEnhancer

getClassLoaderResolver, getClassMetaData, getClassName, getFieldsList, getMetaDataManager, getMethodsList, hasOption, initialise, isPersistable, requiresDetachable, save, setOptions

Methods inherited from class java.lang.Object

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

Field Detail

inputResourceName

protected String inputResourceName

Resource name of the input class (only when the class exists in a class file).

inputBytes

protected byte[] inputBytes

Bytes of the input class (only when enhancing generated classes with no class file).

cls

protected final Class cls

Class that is being enhanced.

classBytes

protected byte[] classBytes

Bytes of the class (after enhancing).

pkClassBytes

protected byte[] pkClassBytes

Bytes for any auto-generated PK class (if generated during enhancement).

asmClassName

protected String asmClassName

ASM Class name for this class (replace . with /).

classDescriptor

protected String classDescriptor

Class descriptor for this class.

namer

protected EnhancementNamer namer

Constructor Detail

JDOClassEnhancer

public JDOClassEnhancer(ClassMetaData cmd,
                ClassLoaderResolver clr,
                MetaDataManager mmgr)

Constructor for an enhancer for the class. The class is assumed to be in the CLASSPATH.

Parameters:

cmd - MetaData for the class to be enhanced

clr - ClassLoader resolver

mmgr - MetaData manager

JDOClassEnhancer

public JDOClassEnhancer(ClassMetaData cmd,
                ClassLoaderResolver clr,
                MetaDataManager mmgr,
                byte[] classBytes)

Constructor for an enhancer to enhance a class defined by the provided bytes.

Parameters:

cmd - MetaData for the class to be enhanced

clr - ClassLoader resolver

mmgr - MetaData manager

classBytes - Bytes of the class to enhance

Method Detail

setNamer

public void setNamer(EnhancementNamer namer)

getClassNameForFileName

public static String getClassNameForFileName(String filename)

Convenience accessor for the class name that is stored in a particular class.

Parameters:

filename - Name of the file

Returns:

The class name

getClassBeingEnhanced

public Class getClassBeingEnhanced()

Accessor for the class being enhanced.

Returns:

Class being enhanced

getASMClassName

public String getASMClassName()

Accessor for the ASM class name

Returns:

ASM class name

getClassDescriptor

public String getClassDescriptor()

Accessor for the class descriptor for the class being enhanced

Returns:

class descriptor

initialiseMethodsList

protected void initialiseMethodsList()

Method to initialise the list of methods to add.

Specified by:

initialiseMethodsList in class AbstractClassEnhancer

initialiseFieldsList

protected void initialiseFieldsList()

Method to initialise the list of fields to add.

Specified by:

initialiseFieldsList in class AbstractClassEnhancer

enhance

public boolean enhance()

Method to enhance a classes definition.

Returns:

Whether it was enhanced with no errors

getClassBytes

public byte[] getClassBytes()

Accessor for the class bytes. Only has relevance to be called after enhance().

Returns:

The class bytes

getPrimaryKeyClassBytes

public byte[] getPrimaryKeyClassBytes()

Accessor for the primary-key class bytes (if generating a PK). Only has relevance to be called after enhance().

Returns:

The primary-key class bytes

validate

public boolean validate()

Description copied from interface: ClassEnhancer

Validate whether the class is enhanced.

Returns:

Return true if already enhanced class.

checkClassIsEnhanced

protected boolean checkClassIsEnhanced(boolean logErrors)

Convenience method to return if a class is enhanced.

Parameters:

logErrors - Whether to log any errors (missing methods etc) as errors (otherwise info/debug)

Returns:

Whether the class is enhanced

getNamer

public EnhancementNamer getNamer()