| /* |
| * Copyright (c) 2011, 2019 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.ArrayList; |
| import java.util.List; |
| |
| import org.eclipse.persistence.descriptors.ClassDescriptor; |
| 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.ServerSession; |
| |
| /** |
| * PUBLIC: |
| * HashPartitioningPolicy partitions access to a database cluster by the hash of a field value from the object, |
| * such as the object's location, or tenant. |
| * The hash indexes into the list of connection pools. |
| * All write or read request for objects with that hash value are sent to the server. |
| * If a query does not include the field as a parameter, then it can either be sent |
| * to all servers and unioned, or left to the session's default behavior. |
| * @author James Sutherland |
| * @since EclipseLink 2.2 |
| */ |
| public class HashPartitioningPolicy extends FieldPartitioningPolicy { |
| |
| protected List<String> connectionPools = new ArrayList<>(); |
| |
| public HashPartitioningPolicy() { |
| super(); |
| } |
| |
| public HashPartitioningPolicy(String partitionField) { |
| super(partitionField); |
| } |
| |
| public HashPartitioningPolicy(String partitionField, boolean unionUnpartitionableQueries) { |
| super(partitionField, unionUnpartitionableQueries); |
| } |
| |
| /** |
| * INTERNAL: |
| * Default the connection pools to all pools if unset. |
| */ |
| @Override |
| public void initialize(AbstractSession session) { |
| super.initialize(session); |
| if (getConnectionPools().isEmpty() && session.isServerSession()) { |
| getConnectionPools().addAll(((ServerSession)session).getConnectionPools().keySet()); |
| } |
| } |
| |
| /** |
| * PUBLIC: |
| * Return the list of connection pool names to replicate queries to. |
| */ |
| public List<String> getConnectionPools() { |
| return connectionPools; |
| } |
| |
| /** |
| * PUBLIC: |
| * Set the list of connection pool names to replicate queries to. |
| * A connection pool with the same name must be defined on the ServerSession. |
| */ |
| public void setConnectionPools(List<String> connectionPools) { |
| this.connectionPools = connectionPools; |
| } |
| |
| /** |
| * PUBLIC: |
| * Add the connection pool name to the list of pools to rotate queries through. |
| */ |
| public void addConnectionPool(String connectionPool) { |
| getConnectionPools().add(connectionPool); |
| } |
| |
| /** |
| * INTERNAL: |
| * Get a connection from one of the pools in a round robin rotation fashion. |
| */ |
| @Override |
| public List<Accessor> getConnectionsForQuery(AbstractSession session, DatabaseQuery query, AbstractRecord arguments) { |
| Object value = arguments.get(this.partitionField); |
| if (value == null) { |
| if (this.unionUnpartitionableQueries) { |
| // Use all connections. |
| List<Accessor> accessors = new ArrayList<>(this.connectionPools.size()); |
| for (String poolName : this.connectionPools) { |
| accessors.add(getAccessor(poolName, session, query, false)); |
| } |
| return accessors; |
| } else { |
| // Use default behavior. |
| return null; |
| } |
| } |
| int index = computePartitionId(value); |
| if (session.getPlatform().hasPartitioningCallback()) { |
| // UCP support. |
| session.getPlatform().getPartitioningCallback().setPartitionId(index); |
| return null; |
| } |
| // Use the mapped connection pool. |
| List<Accessor> accessors = new ArrayList<>(1); |
| String poolName = this.connectionPools.get(index); |
| accessors.add(getAccessor(poolName, session, query, false)); |
| return accessors; |
| } |
| |
| /** |
| * INTERNAL: |
| * Allow for the persist call to assign the partition. |
| */ |
| @Override |
| public void partitionPersist(AbstractSession session, Object object, ClassDescriptor descriptor) { |
| Object value = extractPartitionValueForPersist(session, object, descriptor); |
| if (value == null) { |
| return; |
| } |
| int index = computePartitionId(value); |
| if (session.getPlatform().hasPartitioningCallback()) { |
| // UCP support. |
| session.getPlatform().getPartitioningCallback().setPartitionId(index); |
| } else { |
| String poolName = this.connectionPools.get(index); |
| getAccessor(poolName, session, null, false); |
| } |
| } |
| |
| //defend against Math.abs(Integer.MIN_VALUE) == Integer.MIN_VALUE |
| private int computePartitionId(Object o) { |
| int hashCode = o.hashCode(); |
| return (hashCode == Integer.MIN_VALUE |
| ? Integer.MAX_VALUE : Math.abs(hashCode)) |
| % this.connectionPools.size(); |
| } |
| } |