Class AbstractDatabaseImpl

java.lang.Object
org.exolab.castor.jdo.engine.AbstractDatabaseImpl
All Implemented Interfaces:
Database
Direct Known Subclasses:
GlobalDatabaseImpl, LocalDatabaseImpl

public abstract class AbstractDatabaseImpl extends Object implements Database
An implementation of the JDO database supporting explicit transaction demarcation.
Version:
$Revision: 8351 $ $Date: 2006-04-22 11:05:30 -0600 (Sat, 22 Apr 2006) $
Author:
Assaf Arkin, Bruce Snyder
  • Field Details

    • _scope

      protected PersistenceInfoGroup _scope
      The database engine used to access the underlying SQL database.
    • _ctx

      protected TransactionContext _ctx
      The transaction context is this database was accessed with an XAResource.
    • _lockTimeout

      protected int _lockTimeout
      The lock timeout for this database. Zero for immediate timeout, an infinite value for no timeout. The timeout is specified in seconds.
    • _callback

      protected CallbackInterceptor _callback
      The default callback interceptor for transaction.
    • _instanceFactory

      protected InstanceFactory _instanceFactory
      The instance factory to that creates new instances of data object.
    • _dbName

      protected String _dbName
      The name of this database.
    • _autoStore

      protected boolean _autoStore
      True if user prefer all reachable object to be stored automatically. False if user want only dependent object to be stored.
    • _classLoader

      protected ClassLoader _classLoader
      The class loader for application classes (may be null).
  • Constructor Details

    • AbstractDatabaseImpl

      public AbstractDatabaseImpl(String dbName, int lockTimeout, CallbackInterceptor callback, InstanceFactory instanceFactory, ClassLoader classLoader, boolean autoStore) throws DatabaseNotFoundException
      Creates an instance of this class.
      Parameters:
      dbName - Name of the database.
      lockTimeout - Lock timeout to use.
      callback - Callback interceptors.
      instanceFactory - Instance factory.
      classLoader - Current class loader.
      autoStore - True if auto storing is enabled.
      Throws:
      DatabaseNotFoundException - If there's no database configuration for the given name.
  • Method Details

    • getLockEngine

      LockEngine getLockEngine()
      Returns the LockEngine in use by this database instance.
      Returns:
      the LockEngine in use by this database instance.
    • getScope

      public PersistenceInfoGroup getScope()
      Specified by:
      getScope in interface Database
    • setAutoStore

      public void setAutoStore(boolean autoStore)
      Indicates whether user prefer all reachable object to be stored automatically; false if user wants dependent object only to be stored.
      Specified by:
      setAutoStore in interface Database
      Parameters:
      autoStore - True to indicate that 'autoStore' mode should be used.
    • isAutoStore

      public boolean isAutoStore()
      Return if the current transaction is set to autoStore, it there is transaction active. If there is no active transaction, return if the next transaction will be set to autoStore.
      Specified by:
      isAutoStore in interface Database
      Returns:
      True if 'auto-store' mode is in use.
    • getClassLoader

      public ClassLoader getClassLoader()
      Gets the current application ClassLoader's instance.
      Specified by:
      getClassLoader in interface Database
      Returns:
      the current ClassLoader's instance, or null if not provided
    • getDatabaseName

      public String getDatabaseName()
      Return the name of the database.
      Specified by:
      getDatabaseName in interface Database
      Returns:
      Name of the database.
    • close

      public abstract void close() throws PersistenceException
      Closes the database. If a client transaction is in progress the transaction will be rolled back and an exception thrown. If an app-server transaction is in progress, the transaction will commit/rollback when triggered by the application server.
      Specified by:
      close in interface Database
      Throws:
      PersistenceException - An error occured while attempting to close the database
    • isClosed

      public boolean isClosed()
      Returns true if the database is closed.
      Specified by:
      isClosed in interface Database
      Returns:
      True if the database is closed
    • isLocked

      public boolean isLocked(Class cls, Object identity) throws PersistenceException
      Returns true if the specified object is currently locked.
      Specified by:
      isLocked in interface Database
      Parameters:
      cls - Class instance.
      identity - Object identity.
      Returns:
      True if the object specified is locked; false otherwise.
      Throws:
      PersistenceException
    • load

      public <T> T load(Class<T> type, Object identity) throws PersistenceException
      Load an object of the specified type and given identity. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object. If the identity spans on more than one field, all of the identity fields can be wrapped in a Complex object.
      Specified by:
      load in interface Database
      Parameters:
      type - The object's type
      identity - The object's identity
      Returns:
      The object instance.
      Throws:
      PersistenceException - An error reported by the persistence engine
    • load

      public <T> T load(Class<T> type, Object identity, Object object) throws PersistenceException

      Load an object of the specified type and given identity into a given instance of object. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object. If the identity spans on more than one field, all of the identity fields can be wrapped in a Complex object.

      Specified by:
      load in interface Database
      Parameters:
      type - The object's type
      identity - The object's identity
      object - The object instance to be loaded into
      Returns:
      The object instance.
      Throws:
      PersistenceException - An error reported by the persistence engine
    • load

      public <T> T load(Class<T> type, Object identity, AccessMode mode) throws PersistenceException

      Load an object of the specified type and given identity. Once loaded the object is persistent. Calling this method with the same identity in the same transaction will return the same object. This method is equivalent to a query that returns a single object.

      Specified by:
      load in interface Database
      Parameters:
      type - The object's type
      identity - The object's identity
      mode - The access mode
      Returns:
      The object instance.
      Throws:
      PersistenceException - An error reported by the persistence engine
    • create

      public void create(Object object) throws PersistenceException
      Creates a new object in persistent storage. The object will be persisted only if the transaction commits.

      If the object has an identity then duplicate identity check happens in this method, and the object is visible to queries in this transaction. If the identity is null, duplicate identity check occurs when the transaction completes and the object is not visible to queries until the transaction commits.

      Specified by:
      create in interface Database
      Parameters:
      object - The object to create
      Throws:
      PersistenceException - An error reported by the persistence engine
    • getCacheManager

      public CacheManager getCacheManager()
      Get's the CacheManager instance. Call getCacheManager for every Database-instances.
      Specified by:
      getCacheManager in interface Database
      Returns:
      the CacheManager-instance.
    • update

      public void update(Object object) throws PersistenceException
      Update a data object which is queried/loaded/created in another transaction. This method is used only for long transaction support. Calling this method for data object queried/loaded/created in the same transaction results in Exception.

      For example, the data object may be sent to a client application and dispayed to a user. After that the objects is being modified in the client application, the object returns back and is update to the database in the second transaction.

      See Long Transaction on Castor website.

      Specified by:
      update in interface Database
      Parameters:
      object - The object to create
      Throws:
      PersistenceException - An error reported by the persistence engine
    • remove

      public void remove(Object object) throws PersistenceException
      Removes the object from persistent storage. The deletion will take effect only if the transaction is committed, but the object is no longer visible to queries in the current transaction and locks for access from other transactions will block until this transaction completes.
      Specified by:
      remove in interface Database
      Parameters:
      object - The object to remove
      Throws:
      PersistenceException - An error reported by the persistence engine
    • isPersistent

      public boolean isPersistent(Object object)
      Returns true if the entity is persistent. An entity is persistent if it was created or loaded but not removed in this transaction. If the entity was created or loaded in another transaction, or there is no open transaction, this method returns false.
      Specified by:
      isPersistent in interface Database
      Parameters:
      object - The entity.
      Returns:
      True if entity is persistent in this transaction.
    • getIdentity

      public Identity getIdentity(Object object) throws PersistenceException
      Returns the object's identity. The identity will be determined by calling the getters of the fields defined as identities in the mapping. If a mapping for the objects class could not be found a ClassNotPersistenceCapableException will be thrown. Null is only returned if the objects identity is null. It is not required to have an active transaction when using this method.

      Note: Prior to 0.9.9.1 release of castor the identity could only be determined if the object took part in the transaction. If this was not the case, the previous implementation also returned null.

      Specified by:
      getIdentity in interface Database
      Parameters:
      object - The object.
      Returns:
      The object's identity, or null.
      Throws:
      PersistenceException - The class is not persistent capable.
    • lock

      public void lock(Object object) throws PersistenceException
      Acquire a soft write lock on the object. Read locks are implicitly available when the object is queried. A write lock is only granted for objects that are created or deleted or for objects loaded in exclusive mode - this method can obtain such a lock explicitly.

      A soft lock is acquired in memory, not in the database. To acquire a lock in the database, use the locked access mode.

      If the object already has a write lock in this transaction or a read lock in this transaction but no read lock in any other transaction, a write lock is obtained. If this object has a read lock in any other transaction this method will block until the other transaction will release its lock. If the timeout has elapsed or a deadlock has been detected, an exception will be thrown but the current lock will be retained.

      Specified by:
      lock in interface Database
      Parameters:
      object - The object to lock
      Throws:
      PersistenceException - An error reported by the persistence engine
    • getOQLQuery

      public OQLQuery getOQLQuery()
      Creates an OQL query with no statement. OQLQuery.create(java.lang.String) must be called before the query can be executed.
      Specified by:
      getOQLQuery in interface Database
      Returns:
      An OQL query
    • getNamedQuery

      public final OQLQuery getNamedQuery(String name) throws PersistenceException
      Creates an OQL query based upon a named query as defined in the mapping file. OQLQuery.create(java.lang.String)
      Specified by:
      getNamedQuery in interface Database
      Parameters:
      name - Name of the (named) query to create.
      Returns:
      An OQL query
      Throws:
      PersistenceException
    • getNativeQuery

      public final OQLQuery getNativeQuery(String sql, Class<?> result) throws PersistenceException
      Creates an OQL query instance based upon a native SQL query and a returning (resulting) class.
      Specified by:
      getNativeQuery in interface Database
      Parameters:
      sql - Native SQL query to be used.
      result - Class that is result of the query.
      Returns:
      An OQL query
      Throws:
      PersistenceException
    • getOQLQuery

      public OQLQuery getOQLQuery(String oql) throws PersistenceException
      Creates an OQL query from the supplied statement.
      Specified by:
      getOQLQuery in interface Database
      Parameters:
      oql - An OQL query statement
      Returns:
      An OQL query
      Throws:
      PersistenceException
    • getQuery

      public Query getQuery()
      Creates an empty query. The query must be created before it can be executed.
      Specified by:
      getQuery in interface Database
      Returns:
      A query
    • getTransaction

      protected TransactionContext getTransaction() throws TransactionNotInProgressException
      Returns the currently active transaction, if any.
      Returns:
      The current active transaction.
      Throws:
      TransactionNotInProgressException - If there's no active transaction.
    • begin

      public abstract void begin() throws PersistenceException
      Begin a new transaction. A transaction must be open in order to query and persist objects.
      Specified by:
      begin in interface Database
      Throws:
      PersistenceException - A transaction is already open on this database, or an error reported by the persistence engine
    • commit

      public abstract void commit() throws TransactionNotInProgressException, TransactionAbortedException
      Commits and closes the transaction. All changes made to persistent objects during the transaction are made persistent; objects created during the transaction are made durable; and, objects removed during the transaction are removed from the database.

      In other words, any modifications to any data objects which are queried/loaded/created/update to this database is automatically stored to the database and visible to subsequence transactions. (ie. update is solely used for long transaction support and should not be called for any data object queried/loaded/created in the this transaction.)

      If the transaction cannot commit, the entire transaction rolls back and a TransactionAbortedException exception is thrown.

      After this method returns, the transaction is closed and all persistent objects are transient. Using Database.begin() to open a new transaction will not restore objects to their persistent stage.

      Specified by:
      commit in interface Database
      Throws:
      TransactionNotInProgressException - Method called while transaction is not in progress
      TransactionAbortedException - The transaction cannot commit and has been rolled back
    • rollback

      public abstract void rollback() throws TransactionNotInProgressException
      Rolls back and closes the transaction. All changes made to persistent objects during the transaction are lost, objects created during the transaction are not made durable and objects removed during the transaction continue to exist.
      Specified by:
      rollback in interface Database
      Throws:
      TransactionNotInProgressException - Method called while transaction is not in progress
    • isActive

      public boolean isActive()
      Returns true if a transaction is currently active.
      Specified by:
      isActive in interface Database
      Returns:
      True if a transaction is active
    • toString

      public String toString()
      Overrides:
      toString in class Object
    • getJdbcConnection

      public abstract Connection getJdbcConnection() throws PersistenceException
      Gets the underlying JDBC connection. This is for advanced use only. Please make sure that you never close this Connection instance, as it will be closed by Castor.
      Specified by:
      getJdbcConnection in interface Database
      Returns:
      the underlying JDBC connection, if present; otherwise null
      Throws:
      PersistenceException - If the underlying JDBC connection cannot be obtained.
    • loadSynchronizables

      protected void loadSynchronizables()
      Load the TxSynchronizable implementations from the properties file, if not loaded before.
    • registerSynchronizables

      protected void registerSynchronizables()
      Register the TxSynchronizable implementations at the TransactionContect at end of begin().
    • unregisterSynchronizables

      protected void unregisterSynchronizables()
      Unregister the TxSynchronizable implementations at the TransactionContect after commit() or rollback().
    • getCurrentTransaction

      public TransactionContext getCurrentTransaction() throws TransactionNotInProgressException
      Gets the current Castor transaction in use.
      Returns:
      the current Castor
      Throws:
      TransactionNotInProgressException - If there's no transaction in progress.