Package org.eclipse.persistence.dynamic

Class 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

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, loadClass, registerAsParallelCapable, resolveClass, resources, 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.

      • 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

      • addEnum

        public void addEnum​(java.lang.String className,
                    java.lang.Object... literalLabels)

      • 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: