Class DatabaseClasses

  • All Implemented Interfaces:
    ClassFactory, ModuleControl
    Direct Known Subclasses:
    ReflectClassesJava2

    abstract class DatabaseClasses
    extends java.lang.Object
    implements ClassFactory, ModuleControl
    An abstract implementation of the ClassFactory. This package can be extended to fully implement a ClassFactory. Implementations can differ in two areas, how they load a class and how they invoke methods of the generated class.

    This class manages a hash table of loaded generated classes and their GeneratedClass objects. A loaded class may be referenced multiple times -- each class has a reference count associated with it. When a load request arrives, if the class has already been loaded, its ref count is incremented. For a remove request, the ref count is decremented unless it is the last reference, in which case the class is removed. This is transparent to users.

    See Also:
    ClassFactory
    • Constructor Detail

      • DatabaseClasses

        DatabaseClasses()
    • Method Detail

      • boot

        public void boot​(boolean create,
                         java.util.Properties startParams)
                  throws StandardException
        Description copied from interface: ModuleControl
        Boot this module with the given properties. Creates a module instance that can be found using the findModule() methods of Monitor. The module can only be found using one of these findModule() methods once this method has returned.

        An implementation's boot method can throw StandardException. If it is thrown the module is not registered by the monitor and therefore cannot be found through a findModule(). In this case the module's stop() method is not called, thus throwing this exception must free up any resources.

        When create is true the contents of the properties object will be written to the service.properties of the persistent service. Thus any code that requires an entry in service.properties must explicitly place the value in this properties set using the put method.
        Typically the properties object contains one or more default properties sets, which are not written out to service.properties. These default sets are how callers modify the create process. In a JDBC connection database create the first set of defaults is a properties object that contains the attributes that were set on the jdbc:derby: URL. This attributes properties set has the second default properties set as its default. This set (which could be null) contains the properties that the user set on their DriverManager.getConnection() call, and are thus not owned by Derby code, and thus must not be modified by Derby code.

        When create is false the properties object contains all the properties set in the service.properties file plus a limited number of attributes from the JDBC URL attributes or connection properties set. This avoids properties set by the user compromising the boot process. An example of a property passed in from the JDBC world is the bootPassword for encrypted databases.

        Code should not hold onto the passed in properties reference after boot time as its contents may change underneath it. At least after the complete boot is completed, the links to all the default sets will be removed.

        Specified by:
        boot in interface ModuleControl
        Throws:
        StandardException - Module cannot be started.
        See Also:
        Monitor, ModuleFactory
      • stop

        public void stop()
        Description copied from interface: ModuleControl
        Stop the module. The module may be found via a findModule() method until some time after this method returns. Therefore the factory must be prepared to reject requests to it once it has been stopped. In addition other modules may cache a reference to the module and make requests of it after it has been stopped, these requests should be rejected as well.
        Specified by:
        stop in interface ModuleControl
        See Also:
        Monitor, ModuleFactory
      • WriteClassFile

        private static void WriteClassFile​(java.lang.String fullyQualifiedName,
                                           ByteArray bytecode,
                                           java.lang.Throwable t)
      • loadApplicationClass

        public final java.lang.Class loadApplicationClass​(java.lang.String className)
                                                   throws java.lang.ClassNotFoundException
        Description copied from interface: ClassFactory
        Load an application class, or a class that is potentially an application class.
        Specified by:
        loadApplicationClass in interface ClassFactory
        Throws:
        java.lang.ClassNotFoundException - Class cannot be found, or a SecurityException or LinkageException was thrown loading the class.
      • loadClassNotInDatabaseJar

        abstract java.lang.Class loadClassNotInDatabaseJar​(java.lang.String className)
                                                    throws java.lang.ClassNotFoundException
        Throws:
        java.lang.ClassNotFoundException
      • loadApplicationClass

        public final java.lang.Class loadApplicationClass​(java.io.ObjectStreamClass classDescriptor)
                                                   throws java.lang.ClassNotFoundException
        Description copied from interface: ClassFactory
        Load an application class, or a class that is potentially an application class.
        Specified by:
        loadApplicationClass in interface ClassFactory
        Throws:
        java.lang.ClassNotFoundException - Class cannot be found, or a SecurityException or LinkageException was thrown loading the class.
      • isApplicationClass

        public boolean isApplicationClass​(java.lang.Class theClass)
        Description copied from interface: ClassFactory
        Was the passed in class loaded by a ClassManager.
        Specified by:
        isApplicationClass in interface ClassFactory
        Returns:
        true if the class was loaded by a Derby class manager, false it is was loaded by the system class loader, or another class loader.
      • getClassLoaderVersion

        public int getClassLoaderVersion()
        Description copied from interface: ClassFactory
        Return the in-memory "version" of the class manager. The version is bumped everytime the classes are re-loaded.
        Specified by:
        getClassLoaderVersion in interface ClassFactory
      • loadGeneratedClassFromData

        abstract LoadedGeneratedClass loadGeneratedClassFromData​(java.lang.String fullyQualifiedName,
                                                                 ByteArray classDump)
      • getMonitor

        private static ModuleFactory getMonitor()
        Privileged Monitor lookup. Must be private so that user code can't call this entry point.