Package com.sleepycat.persist.model

Class EntityModel

java.lang.Object

com.sleepycat.persist.model.EntityModel

Direct Known Subclasses:

AnnotationModel

public abstract class EntityModel
extends java.lang.Object

The base class for classes that provide entity model metadata. An EntityModel defines entity classes, primary keys, secondary keys, and relationships between entities. For each entity class that is part of the model, a single PrimaryIndex object and zero or more SecondaryIndex objects may be accessed via an EntityStore.

The built-in entity model, the AnnotationModel, is based on annotations that are added to entity classes and their key fields. Annotations are used in the examples in this package, and it is expected that annotations will normally be used; most readers should therefore skip to the AnnotationModel class. However, a custom entity model class may define its own metadata. This can be used to define entity classes and keys using mechanisms other than annotations.

A concrete entity model class should extend this class and implement the getClassMetadata(java.lang.String), getEntityMetadata(java.lang.String) and getKnownClasses() methods.

This is an abstract class rather than an interface to allow adding capabilities to the model at a future date without causing incompatibilities. For example, a method may be added in the future for returning new information about the model and subclasses may override this method to return the new information. Any new methods will have default implementations that return default values, and the use of the new information will be optional.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	EntityModel()	The default constructor for use by subclasses.

Method Summary

Modifier and Type	Method	Description
static java.lang.Class	classForName(java.lang.String className)	Deprecated. use resolveClass(java.lang.String) instead.
java.lang.Object	convertRawObject(RawObject raw)	Converts a given raw object to a live object according to the current class definitions.
java.util.List<RawType>	getAllRawTypes()	Returns all versions of all known types.
java.util.List<RawType>	getAllRawTypeVersions(java.lang.String className)	Returns all known versions of type information for a given class name, or null if no persistent version of the class is known.
abstract ClassMetadata	getClassMetadata(java.lang.String className)	Returns the metadata for a given persistent class name, including proxy classes and entity classes.
abstract EntityMetadata	getEntityMetadata(java.lang.String className)	Returns the metadata for a given entity class name.
abstract java.util.Set<java.lang.String>	getKnownClasses()	Returns the names of all known persistent classes.
java.util.Set<java.lang.String>	getKnownSpecialClasses()	Returns the names of all known persistent enum and array classes that may be used to store persistent data.
RawType	getRawType(java.lang.String className)	Returns the type information for the current version of a given class, or null if the class is not currently persistent.
RawType	getRawTypeVersion(java.lang.String className, int version)	Returns the type information for a given version of a given class, or null if the given version of the class is unknown.
boolean	isOpen()	Returns whether the model is associated with an open store.
void	registerClass(java.lang.Class persistentClass)	Registers a persistent class, most importantly, a PersistentProxy class or entity subclass.
java.lang.Class	resolveClass(java.lang.String className)	Should be called by entity model implementations instead of calling Class.forName whenever loading an application class.
protected void	setCatalog(com.sleepycat.persist.impl.PersistCatalog newCatalog)	Internal access method that should not be used by applications.

Methods inherited from class java.lang.Object

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

Constructor Detail

EntityModel

protected EntityModel()

The default constructor for use by subclasses.

Method Detail

isOpen

public final boolean isOpen()

Returns whether the model is associated with an open store.

The registerClass(java.lang.Class) method may only be called when the model is not yet open. Certain other methods may only be called when the model is open:

• convertRawObject(com.sleepycat.persist.raw.RawObject)
• getAllRawTypeVersions(java.lang.String)
• getRawType(java.lang.String)
• getRawTypeVersion(java.lang.String, int)

Returns:

whether the model is associated with an open store.

registerClass

public final void registerClass(java.lang.Class persistentClass)

Registers a persistent class, most importantly, a PersistentProxy class or entity subclass. Also registers an enum or array class.

Any persistent class , enum class or array may be registered in advance of using it, to avoid the overhead of updating the catalog database when an instance of the class is first stored. This method must be called in three cases:

1. to register all PersistentProxy classes, and
2. to register an entity subclass defining a secondary key, if getSubclassIndex is not called for the subclass, and
3. to register all new enum or array classes, if the these enum or array classes are unknown for DPL but will be used in a Converter mutation.

For example:

 EntityModel model = new AnnotationModel();
 model.registerClass(MyProxy.class);
 model.registerClass(MyEntitySubclass.class);
 model.registerClass(MyEnum.class);
 model.registerClass(MyArray[].class);

 StoreConfig config = new StoreConfig();
 ...
 config.setModel(model);

 EntityStore store = new EntityStore(..., config);

This method must be called before opening a store based on this model.

Parameters:

persistentClass - the class to register.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is associated with an open store.

java.lang.IllegalArgumentException - if the given class is not persistent or has a different class loader than previously registered classes.

setCatalog

protected void setCatalog(com.sleepycat.persist.impl.PersistCatalog newCatalog)

Internal access method that should not be used by applications. This method is used to initialize the model when catalog creation is complete, and reinitialize it when a Replica refresh occurs. See Store.refresh.

Parameters:

newCatalog - the catalog.

getClassMetadata

public abstract ClassMetadata getClassMetadata(java.lang.String className)

Returns the metadata for a given persistent class name, including proxy classes and entity classes.

Parameters:

className - the class name.

Returns:

the metadata or null if the class is not persistent or does not exist.

getEntityMetadata

public abstract EntityMetadata getEntityMetadata(java.lang.String className)

Returns the metadata for a given entity class name.

Parameters:

className - the class name.

Returns:

the metadata or null if the class is not an entity class or does not exist.

getKnownClasses

public abstract java.util.Set<java.lang.String> getKnownClasses()

Returns the names of all known persistent classes. A type becomes known when an instance of the type is stored for the first time or metadata or type information is queried for a specific class name.

Returns:

an unmodifiable set of class names.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

getKnownSpecialClasses

public java.util.Set<java.lang.String> getKnownSpecialClasses()

Returns the names of all known persistent enum and array classes that may be used to store persistent data. This differs from getKnownClasses(), which does not return enum and array classes because they have no metadata.

Returns:

an unmodifiable set of enum and array class names.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

getRawType

public final RawType getRawType(java.lang.String className)

Returns the type information for the current version of a given class, or null if the class is not currently persistent.

Parameters:

className - the name of the current version of the class.

Returns:

the RawType.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

getRawTypeVersion

public final RawType getRawTypeVersion(java.lang.String className,
                                       int version)

Returns the type information for a given version of a given class, or null if the given version of the class is unknown.

Parameters:

className - the name of the latest version of the class.

version - the desired version of the class.

Returns:

the RawType.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

getAllRawTypeVersions

public final java.util.List<RawType> getAllRawTypeVersions(java.lang.String className)

Returns all known versions of type information for a given class name, or null if no persistent version of the class is known.

Parameters:

className - the name of the latest version of the class.

Returns:

an unmodifiable list of types for the given class name in order from most recent to least recent.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

getAllRawTypes

public final java.util.List<RawType> getAllRawTypes()

Returns all versions of all known types.

Returns:

an unmodifiable list of types.

Throws:

java.lang.IllegalStateException - if this method is called for a model that is not associated with an open store.

convertRawObject

public final java.lang.Object convertRawObject(RawObject raw)

Converts a given raw object to a live object according to the current class definitions.

The given raw object must conform to the current class definitions. However, the raw type (RawObject.getType()) is allowed to be from a different store, as long as the class names and the value types match. This allows converting raw objects that are read from one store to live objects in another store, for example, in a conversion program.

Parameters:

raw - the RawObject.

Returns:

the live object.

resolveClass

public java.lang.Class resolveClass(java.lang.String className)
                             throws java.lang.ClassNotFoundException

Should be called by entity model implementations instead of calling Class.forName whenever loading an application class. This method honors the BDB JE environment's ClassLoader property and uses ClassResolver to implement the class loading policy.

Parameters:

className - the class name.

Returns:

the Class.

Throws:

java.lang.ClassNotFoundException - if the class is not found.

classForName

@Deprecated
public static java.lang.Class classForName(java.lang.String className)
                                    throws java.lang.ClassNotFoundException

Deprecated.

use resolveClass(java.lang.String) instead. This method does not use the environment's ClassLoader property.

Parameters:

className - the class name.

Returns:

the Class.

Throws:

java.lang.ClassNotFoundException - if the class is not found.