| /* |
| * Copyright (c) 2011, 2021 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // Contributors: |
| // James Sutherland (Oracle) - initial API and implementation |
| package org.eclipse.persistence.descriptors.partitioning; |
| |
| import java.util.List; |
| |
| import org.eclipse.persistence.descriptors.ClassDescriptor; |
| import org.eclipse.persistence.exceptions.QueryException; |
| import org.eclipse.persistence.internal.databaseaccess.Accessor; |
| import org.eclipse.persistence.internal.sessions.AbstractRecord; |
| import org.eclipse.persistence.internal.sessions.AbstractSession; |
| import org.eclipse.persistence.queries.DatabaseQuery; |
| import org.eclipse.persistence.sessions.server.ClientSession; |
| import org.eclipse.persistence.sessions.server.ConnectionPool; |
| import org.eclipse.persistence.sessions.server.ServerSession; |
| |
| /** |
| * PUBLIC: |
| * A PartitioningPolicy is used to partition the data for a class across multiple difference databases |
| * or across a database cluster such as Oracle RAC. |
| * Partitioning can provide improved scalability by allowing multiple database machines to service requests. |
| * <p> |
| * If multiple partitions are used to process a single transaction, JTA should be used for proper XA transaction support. |
| * @author James Sutherland |
| * @since EclipseLink 2.2 |
| */ |
| public abstract class PartitioningPolicy implements java.io.Serializable { |
| /** The persistent unit unique name for the policy. */ |
| protected String name; |
| |
| /** |
| * Default constructor. |
| */ |
| protected PartitioningPolicy() { |
| } |
| |
| public abstract List<Accessor> getConnectionsForQuery(AbstractSession session, DatabaseQuery query, AbstractRecord arguments); |
| |
| /** |
| * INTERNAL: |
| * Allow for the persist call to assign the partition. |
| */ |
| public void partitionPersist(AbstractSession session, Object object, ClassDescriptor descriptor) { } |
| |
| /** |
| * INTERNAL: |
| * Initialize the policy. |
| */ |
| public void initialize(AbstractSession session) { } |
| |
| /** |
| * INTERNAL: |
| * Convert all the class-name-based settings to actual class-based |
| * settings. This method is used when converting a project that has been built |
| * with class names to a project with classes. |
| */ |
| public void convertClassNamesToClasses(ClassLoader classLoader) { } |
| |
| /** |
| * INTERNAL: |
| * Return an accessor from the pool. |
| */ |
| public Accessor acquireAccessor(String poolName, ServerSession session, DatabaseQuery query, boolean returnNullIfDead) { |
| ConnectionPool pool = session.getConnectionPool(poolName); |
| if (pool == null) { |
| throw QueryException.missingConnectionPool(poolName, query); |
| } |
| if (returnNullIfDead && pool.isDead()) { |
| return null; |
| } |
| return pool.acquireConnection(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return an accessor from the pool for the session. |
| * For a client session the accessor is stored for the duration of the transaction. |
| */ |
| public Accessor getAccessor(String poolName, AbstractSession session, DatabaseQuery query, boolean returnNullIfDead) { |
| Accessor accessor = null; |
| if (session.isClientSession()) { |
| ClientSession client = (ClientSession)session; |
| // If the client session is exclusive and has a connection then just use the existing connection. |
| if (client.isExclusiveIsolatedClientSession() && client.hasWriteConnection()) { |
| accessor = client.getWriteConnection(); |
| } else { |
| accessor = client.getWriteConnections().get(poolName); |
| if (accessor == null) { |
| accessor = acquireAccessor(poolName, client.getParent(), query, returnNullIfDead); |
| // Assign a write connection for the duration of the transaction. |
| if (client.isExclusiveIsolatedClientSession() || session.isInTransaction()) { |
| accessor = client.addWriteConnection(poolName, accessor); |
| } |
| } |
| } |
| } else if (session.isServerSession()) { |
| accessor = acquireAccessor(poolName, (ServerSession)session, query, returnNullIfDead); |
| } else { |
| throw QueryException.partitioningNotSupported(session, query); |
| } |
| return accessor; |
| } |
| |
| /** |
| * PUBLIC: |
| * Return the name of the policy. |
| * The name must be unique for the persistence unit. |
| * The name allows the policy to be shared among multiple descriptors, queries. |
| */ |
| public String getName() { |
| return name; |
| } |
| |
| /** |
| * PUBLIC: |
| * Set the name of the policy. |
| * The name must be unique for the persistence unit. |
| * The name allows the policy to be shared among multiple descriptors, queries. |
| */ |
| public void setName(String name) { |
| this.name = name; |
| } |
| |
| } |