com.splicemachine.db.impl.services.reflect

Class DatabaseClasses

java.lang.Object

com.splicemachine.db.impl.services.reflect.DatabaseClasses

All Implemented Interfaces:

ClassFactory, ModuleControl

Direct Known Subclasses:

ReflectClassesJava2, SpliceReflectClasses

public 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 Summary

Constructors

Constructor and Description
DatabaseClasses()

Method Summary

Modifier and Type	Method and Description
void	boot(boolean create, java.util.Properties startParams) Boot this module with the given properties.
ByteArray	buildSpecificFactory(java.lang.String className, java.lang.String factoryName)
ClassInspector	getClassInspector() Return a ClassInspector object
int	getClassLoaderVersion() Return the in-memory "version" of the class manager.
boolean	isApplicationClass(java.lang.Class theClass) Was the passed in class loaded by a ClassManager.
java.lang.Class	loadApplicationClass(java.io.ObjectStreamClass classDescriptor) Load an application class, or a class that is potentially an application class.
java.lang.Class	loadApplicationClass(java.lang.String className) Load an application class, or a class that is potentially an application class.
protected abstract java.lang.Class	loadClassNotInDatabaseJar(java.lang.String className)
GeneratedClass	loadGeneratedClass(java.lang.String fullyQualifiedName, ByteArray classDump) Here we load the newly added class now, rather than waiting for the findGeneratedClass().
protected abstract LoadedGeneratedClass	loadGeneratedClassFromData(java.lang.String fullyQualifiedName, ByteArray classDump)
protected ClassInspector	makeClassInspector(DatabaseClasses dc) For creating the class inspector.
void	notifyModifyClasspath(java.lang.String classpath) Notify the class manager that the classpath has been modified.
void	notifyModifyJar(boolean reload) Notify the class manager that a jar file has been modified.
void	stop() Stop the module.

Methods inherited from class java.lang.Object

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

Constructor Detail

DatabaseClasses

public 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:splice: 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

makeClassInspector

protected ClassInspector makeClassInspector(DatabaseClasses dc)

For creating the class inspector. On Java 5 and higher, we have a more capable class inspector.

loadGeneratedClass

public final GeneratedClass loadGeneratedClass(java.lang.String fullyQualifiedName,
                                               ByteArray classDump)
                                        throws StandardException

Here we load the newly added class now, rather than waiting for the findGeneratedClass(). Thus we are assuming that the class is going to be used sometime soon. Delaying the load would mean storing the class data in a file, this wastes cycles and compilcates the cleanup.

Specified by:

loadGeneratedClass in interface ClassFactory

Throws:

StandardException - Class format is bad.

See Also:

ClassFactory.loadGeneratedClass(java.lang.String, com.splicemachine.db.iapi.util.ByteArray)

getClassInspector

public ClassInspector getClassInspector()

Description copied from interface: ClassFactory

Return a ClassInspector object

Specified by:

getClassInspector in interface ClassFactory

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

protected 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.

notifyModifyJar

public void notifyModifyJar(boolean reload)
                     throws StandardException

Description copied from interface: ClassFactory

Notify the class manager that a jar file has been modified.

Specified by:

notifyModifyJar in interface ClassFactory

Parameters:

reload - Restart any attached class loader

Throws:

StandardException - thrown on error

notifyModifyClasspath

public void notifyModifyClasspath(java.lang.String classpath)
                           throws StandardException

Notify the class manager that the classpath has been modified.

Specified by:

notifyModifyClasspath in interface ClassFactory

Throws:

StandardException - thrown on error

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

buildSpecificFactory

public ByteArray buildSpecificFactory(java.lang.String className,
                                      java.lang.String factoryName)
                               throws StandardException

Throws:

StandardException

loadGeneratedClassFromData

protected abstract LoadedGeneratedClass loadGeneratedClassFromData(java.lang.String fullyQualifiedName,
                                                                   ByteArray classDump)