com.sptci.prevayler
Class ObjectGraphSystem

java.lang.Object
  com.sptci.prevayler.StorageSystem
      com.sptci.prevayler.IndexSystem
          com.sptci.prevayler.ConstraintSystem
              com.sptci.prevayler.SearchSystem
                  com.sptci.prevayler.ObjectGraphSystem

All Implemented Interfaces:

AbstractDatabase<PrevalentObject>, DatabaseSystem, Serializable

Direct Known Subclasses:

PrevalentSystem

abstract class ObjectGraphSystem
extends SearchSystem

Abstracts all the code for decomposing and reconstituting object graphs for the prevalent system. Due to the inherent limitations in object serialisation, this step is necessary to ensure that de-serialised objects contain proper references to other prevalent objects and not local copies.

© Copyright 2008 Sans Pareil Technologies, Inc.

Version:

$Id: ObjectGraphSystem.java 22 2008-11-24 19:04:25Z sptrakesh $

Author:

Rakesh Vidyadharan 2008-05-23

Nested Class Summary

Nested classes/interfaces inherited from class com.sptci.prevayler.StorageSystem

StorageSystem.TaskQueue

Field Summary

private static long

serialVersionUID

Fields inherited from class com.sptci.prevayler.SearchSystem

CLASS_FIELD, DOCUMENT_ID_FIELD, OBJECT_ID_FIELD, reader, SAVE_COUNT, searcher, SEPARATOR_CHAR, writer

Fields inherited from class com.sptci.prevayler.StorageSystem

logger

Constructor Summary

ObjectGraphSystem()

Method Summary

protected PrevalentObject	compose(PrevalentObject object) Create a clone of the specified prevalent object and reconstitute object references to other prevalent objects.
protected PrevalentObject	decompose(PrevalentObject object, Date executionTime) Clone the specified object and decouple references to other prevalent object to make suitable for storage in the prevalent system.
private void	decomposeCollection(PrevalentObject object, Field field, Date executionTime) Decompose a collection or references to other prevalent objects in the prevalent object being managed.
private void	decomposeObject(PrevalentObject object, Field field, Date executionTime) Decompose a direct reference represented by the specified field in the prevalent object.
private void	populateReference(PrevalentObject object) Populate the references to other prevalent objects in the specified prevalent object.
protected void	update(Field field, PrevalentObject object, Date executionTime) Replace the prevalent object in the field specified from the specified object prevalent object to the po object that exists in the system.

Methods inherited from class com.sptci.prevayler.SearchSystem

index, remove, search

Methods inherited from class com.sptci.prevayler.ConstraintSystem

checkFields, checkUnique, checkUnique, indexClass, indexFields, preAdd, preDelete, preDelete

Methods inherited from class com.sptci.prevayler.StorageSystem

generateOid, getIndexStorage, getIndexStorage, getPrimaryStorage, getPrimaryStorage, getReferenceStorage, getReferenceStorage, getRelationStorage, getRelationStorage, getTaskQueue

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.sptci.prevayler.DatabaseSystem

delete, save

Methods inherited from interface com.sptci.prevayler.AbstractDatabase

count, fetch, fetch, fetch, fetchIntersection, fetchUnion, search

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

ObjectGraphSystem

ObjectGraphSystem()

Method Detail

compose

protected PrevalentObject compose(PrevalentObject object)
                           throws PrevalentException

Create a clone of the specified prevalent object and reconstitute object references to other prevalent objects. Reads in the references from StorageSystem.referenceMap and reconstitutes the references. Recursively invokes this method on prevalent objects to ensure that the entire object graph is replicated.

Parameters:

object - The object that is to be cloned and reconstituted.

Returns:

The reconstituted prevalent object that represents a persisted prevalent object.

Throws:

PrevalentException - If errors are encountered while reconsituting the prevalent object.

See Also:

populateReference(com.sptci.prevayler.PrevalentObject)

populateReference

private void populateReference(PrevalentObject object)
                        throws PrevalentException,
                               IllegalAccessException

Populate the references to other prevalent objects in the specified prevalent object.

Parameters:

object - The prevalent object that is being reconstituted.

Throws:

PrevalentException - If errors are encountered while fetching the references to the other prevalent objects.

IllegalAccessException - If errors are encountered while setting the field values.

decompose

protected PrevalentObject decompose(PrevalentObject object,
                                    Date executionTime)
                             throws PrevalentException

Clone the specified object and decouple references to other prevalent object to make suitable for storage in the prevalent system. Updates StorageSystem.referenceMap with references that are decomposed.

If a referenced persistent object is not yet persistent, then it is made persistent following persistence by reachability principle. This addition is affected by invoked SearchSystem.save(com.sptci.prevayler.PrevalentObject, org.apache.lucene.document.Document) on the referenced object resulting in persisting the entire object graph through reachability.

Parameters:

object - The object that is to be cloned and decoupled.

executionTime - The datetime at which the transaction was executed.

Returns:

The decomposed prevalent object.

Throws:

PrevalentException - If errors are encountered while processing the class fields.

See Also:

AbstractDatabase.fetch( Class, Object )

decomposeObject

private void decomposeObject(PrevalentObject object,
                             Field field,
                             Date executionTime)
                      throws PrevalentException

Decompose a direct reference represented by the specified field in the prevalent object.

Parameters:

object - The prevalent object to decompose.

field - The field that contains a direct reference to another prevalent object.

executionTime - The datetime at which the transaction was executed.

Throws:

PrevalentException - If errors are encountered while accessing the field.

decomposeCollection

private void decomposeCollection(PrevalentObject object,
                                 Field field,
                                 Date executionTime)
                          throws PrevalentException

Decompose a collection or references to other prevalent objects in the prevalent object being managed.

Parameters:

object - The prevalent object that is to be decomposed prior to storage in the system.

field - The field that contains a collection of references to other prevalent objects.

executionTime - The datetime at which the transaction was executed.

Throws:

PrevalentException - If errors are encountered while fetching the fields of the prevalent object.

update

protected void update(Field field,
                      PrevalentObject object,
                      Date executionTime)
               throws PrevalentException

Replace the prevalent object in the field specified from the specified object prevalent object to the po object that exists in the system.

Parameters:

field - The field whose value is being updated.

object - The prevalent object that is being updated.

executionTime - The datetime at which the transaction was executed.

Throws:

ConstraintException - If the field is marked as unique and the newObject specified is already associated with another prevalent object of the same type.

PrevalentException - If errors are encountered while setting the value of the field.

See Also:

ConstraintSystem.checkUnique(com.sptci.prevayler.PrevalentObject)