DynamicClassLoader (EclipseLink 2.6.1, API Reference)

java.lang.Object
- java.lang.ClassLoader
- - org.eclipse.persistence.dynamic.DynamicClassLoader

```
public class DynamicClassLoader
extends java.lang.ClassLoader
```
This custom ClassLoader provides support for dynamically generating classes within an EclipseLink application using byte codes created using a DynamicClassWriter. A DynamicClassLoader requires a parent or delegate class-loader which is provided to the constructor. This delegate class loader handles the lookup and storage of all created classes.

Author:

dclarke, mnorman

Since:

EclipseLink 1.2

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class DynamicClassLoader.EnumInfo

Nested Classes
Modifier and Type	Class and Description
`static class`	`DynamicClassLoader.EnumInfo`

Field Summary

Fields
Modifier and Type	Field and Description
`protected java.util.Map<java.lang.String,EclipseLinkClassWriter>`	`classWriters` Map of `DynamicClassWriter` used to dynamically create a class in the `findClass(String)` call.
`DynamicClassWriter`	`defaultWriter` Default writer to use if one is not specified.
`protected java.util.Map<java.lang.String,DynamicClassLoader.EnumInfo>`	`enumInfoRegistry`

Constructor Summary

Constructors
Constructor and Description
`DynamicClassLoader(java.lang.ClassLoader delegate)` Create a DynamicClassLoader providing the delegate loader and leaving the defaultWriter as `DynamicClassWriter`
`DynamicClassLoader(java.lang.ClassLoader delegate, DynamicClassWriter writer)` Create a DynamicClassLoader providing the delegate loader and a default `DynamicClassWriter`.

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addClass(java.lang.String className)` Register a class to be dynamically created using the default `DynamicClassWriter`.
`void`	`addClass(java.lang.String className, java.lang.Class<?> parentClass)` Register a class to be dynamically created using a copy of default `DynamicClassWriter` but specifying a different parent class.
`void`	`addClass(java.lang.String className, EclipseLinkClassWriter writer)` Register a class to be dynamically created using the provided `DynamicClassWriter`.
`void`	`addEnum(java.lang.String className, java.lang.Object... literalLabels)`
`protected java.lang.Class<?>`	`checkAssignable(java.lang.Class<?> clz)`
`java.lang.Class<?>`	`createDynamicClass(java.lang.String className)` Create a new dynamic entity type for the specified name assuming the use of the default writer and its default parent class.
`java.lang.Class<?>`	`createDynamicClass(java.lang.String className, java.lang.Class<?> parentClass)` Create a new dynamic entity type for the specified name with the specified parent class.
`java.lang.Class<?>`	`createDynamicClass(java.lang.String className, DynamicClassWriter writer)` Create a dynamic class registering a writer and then forcing the provided class name to be loaded.
`protected java.lang.Class<?>`	`defineDynamicClass(java.lang.String name, byte[] b)` Converts an array of bytes into an instance of class `Class`.
`protected java.lang.Class<?>`	`findClass(java.lang.String className)` Create a new dynamic class if a ClassWriter is registered for the provided className.
`EclipseLinkClassWriter`	`getClassWriter(java.lang.String className)`
`protected java.util.Map<java.lang.String,EclipseLinkClassWriter>`	`getClassWriters()`
`DynamicClassWriter`	`getDefaultWriter()`
`static DynamicClassLoader`	`lookup(Session session)` Lookup the DynamicConversionManager for the given session.

Methods inherited from class java.lang.ClassLoader
clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findResource, findResources, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - classWriters
```
protected java.util.Map<java.lang.String,EclipseLinkClassWriter> classWriters
```
    Map of DynamicClassWriter used to dynamically create a class in the findClass(String) call. The application must register classes using addClass or createDynameClass prior to the findClass(String) being invoked.
    The map of writers is maintained for the life of this DynamicClassLoader instance to ensure additional requests to create dynamic classes of the same name are properly verified. Duplicate requests for dynamic classes of the same name, same writer type, and the same parent class are permitted but different parent classes or different writer types are not.
  - enumInfoRegistry
```
protected java.util.Map<java.lang.String,DynamicClassLoader.EnumInfo> enumInfoRegistry
```
  - defaultWriter
```
public DynamicClassWriter defaultWriter
```
    Default writer to use if one is not specified.
- Constructor Detail
  - DynamicClassLoader
```
public DynamicClassLoader(java.lang.ClassLoader delegate)
```
    Create a DynamicClassLoader providing the delegate loader and leaving the defaultWriter as DynamicClassWriter
  - DynamicClassLoader
```
public DynamicClassLoader(java.lang.ClassLoader delegate,
                  DynamicClassWriter writer)
```
    Create a DynamicClassLoader providing the delegate loader and a default DynamicClassWriter.
- Method Detail
  - getDefaultWriter
```
public DynamicClassWriter getDefaultWriter()
```
  - getClassWriters
```
protected java.util.Map<java.lang.String,EclipseLinkClassWriter> getClassWriters()
```
  - getClassWriter
```
public EclipseLinkClassWriter getClassWriter(java.lang.String className)
```
  - addEnum
```
public void addEnum(java.lang.String className,
           java.lang.Object... literalLabels)
```
  - addClass
```
public void addClass(java.lang.String className)
```
    Register a class to be dynamically created using the default DynamicClassWriter.
    
    See Also:
    addClass(String, EclipseLinkClassWriter)
  - addClass
```
public void addClass(java.lang.String className,
            java.lang.Class<?> parentClass)
```
    Register a class to be dynamically created using a copy of default DynamicClassWriter but specifying a different parent class.
    
    See Also:
    addClass(String, EclipseLinkClassWriter)
  - addClass
```
public void addClass(java.lang.String className,
            EclipseLinkClassWriter writer)
              throws DynamicException
```
    Register a class to be dynamically created using the provided DynamicClassWriter. The registered writer is used when the findClass(String) method is called back on this loader from the ClassLoader.loadClass(String) call.
    If a duplicate request is made for the same className and the writers are not compatible a DynamicException will be thrown. If the duplicate request contains a compatible writer then the second request is ignored as the class may already have been generated.
    
    Throws:
    
    DynamicException
    See Also:
    findClass(String)
  - createDynamicClass
```
public java.lang.Class<?> createDynamicClass(java.lang.String className,
                                    DynamicClassWriter writer)
```
    Create a dynamic class registering a writer and then forcing the provided class name to be loaded.
  - checkAssignable
```
protected java.lang.Class<?> checkAssignable(java.lang.Class<?> clz)
```
  - createDynamicClass
```
public java.lang.Class<?> createDynamicClass(java.lang.String className)
```
    Create a new dynamic entity type for the specified name assuming the use of the default writer and its default parent class.
    
    See Also:
    createDynamicClass(String, DynamicClassWriter)
  - createDynamicClass
```
public java.lang.Class<?> createDynamicClass(java.lang.String className,
                                    java.lang.Class<?> parentClass)
```
    Create a new dynamic entity type for the specified name with the specified parent class.
    
    See Also:
    createDynamicClass(String, DynamicClassWriter)
  - findClass
```
protected java.lang.Class<?> findClass(java.lang.String className)
                                throws java.lang.ClassNotFoundException
```
    Create a new dynamic class if a ClassWriter is registered for the provided className. This code is single threaded to ensure only one class is created for a given name and that the ClassWriter is removed afterwards.
    
    Overrides:
    
    findClass in class java.lang.ClassLoader
    
    Throws:
    
    java.lang.ClassNotFoundException
  - defineDynamicClass
```
protected java.lang.Class<?> defineDynamicClass(java.lang.String name,
                                    byte[] b)
```
    Converts an array of bytes into an instance of class Class. Before the Class can be used it must be resolved.
    
    Parameters:
    name -
    b -
    
    Throws:
    
    java.lang.ClassFormatError
  - lookup
```
public static DynamicClassLoader lookup(Session session)
```
    Lookup the DynamicConversionManager for the given session. If the existing ConversionManager is not an instance of DynamicConversionManager then create a new one and replace the existing one.
    
    Parameters:
    session -
    
    Returns:

Class DynamicClassLoader

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.ClassLoader

Methods inherited from class java.lang.Object

Field Detail

classWriters

enumInfoRegistry

defaultWriter

Constructor Detail

DynamicClassLoader

DynamicClassLoader

Method Detail

getDefaultWriter

getClassWriters

getClassWriter

addEnum

addClass

addClass

addClass

createDynamicClass

checkAssignable

createDynamicClass

createDynamicClass

findClass

defineDynamicClass

lookup