foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/remote/RemoteConnection.java - eclipselink - Git at Google

 /*
  * Copyright (c) 1998, 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:
 //     Oracle - initial API and implementation from Oracle TopLink
 package org.eclipse.persistence.internal.sessions.remote;

 import java.rmi.server.ObjID;
 import java.util.IdentityHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Vector;

 import org.eclipse.persistence.descriptors.ClassDescriptor;
 import org.eclipse.persistence.queries.CursoredStreamPolicy;
 import org.eclipse.persistence.queries.DatabaseQuery;
 import org.eclipse.persistence.queries.ObjectLevelReadQuery;
 import org.eclipse.persistence.queries.ReadQuery;
 import org.eclipse.persistence.queries.ScrollableCursorPolicy;
 import org.eclipse.persistence.sessions.Login;
 import org.eclipse.persistence.sessions.remote.DistributedSession;

 /**
  * Defines set of abstract methods which one must overwrite for any kind to implement a communication mechanism.
  */
 public abstract class RemoteConnection implements java.io.Serializable {

     /**
      * This attribute is used to provide a globally unique identifier for this connection.
      * It should be the same value as the JNDI context or the RMIRegistry context.
      */
     protected String serviceName;

     /** Back reference to owning session. */
     protected DistributedSession session;

     /**
      * ADVANCED:
      * This method will send the command to the remote session for processing
      * @param remoteCommand Contains a command that will be executed on the remote session
      * @see org.eclipse.persistence.internal.sessions.remote.RemoteCommand
      */
     public abstract void processCommand(RemoteCommand remoteCommand);

     /**
      * Allow the connection to initialize an setting in the session.
      */
     public void initialize(DistributedSession session) {
         this.session = session;
     }

     public DistributedSession getSession() {
         return session;
     }

     public void setSession(DistributedSession session) {
         this.session = session;
     }

     public boolean isConnected() {
         return true;
     }

     /**
      * Begin a transaction on the database.
      */
     public abstract void beginTransaction();

     /**
      * Begin an early unit of work transaction.
      */
     public abstract void beginEarlyTransaction();

     /**
      * Commit remote unit of work
      */
     public abstract RemoteUnitOfWork commitRootUnitOfWork(RemoteUnitOfWork remoteUnitOfWork);

     /**
      * Commit a transaction on the database.
      */
     public abstract void commitTransaction();

     /**
      * Returns remote client session.
      */
     public abstract org.eclipse.persistence.sessions.Session createRemoteSession();

     /**
      * Used for closing cursored streams across RMI.
      */
     public abstract void cursoredStreamClose(ObjID id);

     /**
      * Retrieve next page size of objects from the remote cursored stream
      */
     public abstract Vector cursoredStreamNextPage(RemoteCursoredStream remoteCursoredStream, ReadQuery query, DistributedSession session, int pageSize);

     /**
      * Return the cursored stream size
      */
     public abstract int cursoredStreamSize(ObjID remoteCursoredStreamID);

     /**
      * Get remote cursor stream.
      */
     public abstract RemoteCursoredStream cursorSelectObjects(CursoredStreamPolicy policy, DistributedSession session);

     /**
      * Get remote cursor stream.
      */
     public abstract RemoteScrollableCursor cursorSelectObjects(ScrollableCursorPolicy policy, DistributedSession session);

     /**
      * INTERNAL:
      * Get the read-only classes
      */
     public abstract Vector getDefaultReadOnlyClasses();

     /**
      * Get descriptor
      */
     public abstract ClassDescriptor getDescriptor(Class<?> domainClass);

     /**
      * Get descriptor
      */
     public abstract ClassDescriptor getDescriptorForAlias(String alias);

     /**
      * Return the login informaiton from the server.
      */
     public abstract Login getLogin();

     /**
      * INTERNAL:
      * Perform remote function call
      */
     public abstract Object getSequenceNumberNamed(Object remoteFunctionCall);

     /**
      * ADVANCED:
      * This method is used to get the globally unique identifier for this connection.
      * This identifier should be the same as the JNDI context the service was stored under.
      * @return java.lang.String the name
      */
     public java.lang.String getServiceName() {
         if (serviceName == null) {
             serviceName = "";
         }
         return serviceName;
     }

     public abstract void initializeIdentityMapsOnServerSession();

     /**
      * Instantiated remote value holder.
      */
     public abstract Transporter instantiateRemoteValueHolderOnServer(RemoteValueHolder remoteValueHolder);

     /**
      * Execute query remotely.
      */
     public abstract Transporter remoteExecute(DatabaseQuery query);

     /**
      * Execute query remotely.
      */
     public abstract Transporter remoteExecuteNamedQuery(String name, Class<?> javaClass, Vector arguments);

     /**
      * Rollback a transaction on the database.
      */
     public abstract void rollbackTransaction();

     /**
      * Moves the cursor to the given row number in the result set
      */
     public abstract boolean scrollableCursorAbsolute(ObjID remoteScrollableCursorOid, int rows);

     /**
      * Moves the cursor to the end of the result set, just after the last row.
      */
     public abstract void scrollableCursorAfterLast(ObjID remoteScrollableCursorOid);

     /**
      * Moves the cursor to the front of the result set, just before the first row
      */
     public abstract void scrollableCursorBeforeFirst(ObjID remoteScrollableCursorOid);

     /**
      * Used for closing scrolable cursor across RMI.
      */
     public abstract void scrollableCursorClose(ObjID remoteScrollableCursorOid);

     /**
      * Retrieves the current row index number
      */
     public abstract int scrollableCursorCurrentIndex(ObjID remoteScrollableCursorOid);

     /**
      * Moves the cursor to the first row in the result set
      */
     public abstract boolean scrollableCursorFirst(ObjID remoteScrollableCursorOid);

     /**
      * Indicates whether the cursor is after the last row in the result set.
      */
     public abstract boolean scrollableCursorIsAfterLast(ObjID remoteScrollableCursorOid);

     /**
      * Indicates whether the cursor is before the first row in the result set.
      */
     public abstract boolean scrollableCursorIsBeforeFirst(ObjID remoteScrollableCursorOid);

     /**
      * Indicates whether the cursor is on the first row of the result set.
      */
     public abstract boolean scrollableCursorIsFirst(ObjID remoteScrollableCursorOid);

     /**
      * Indicates whether the cursor is on the last row of the result set.
      */
     public abstract boolean scrollableCursorIsLast(ObjID remoteScrollableCursorOid);

     /**
      * Moves the cursor to the last row in the result set
      */
     public abstract boolean scrollableCursorLast(ObjID remoteScrollableCursorOid);

     /**
      * Retrieve next object from the remote scrollable cursor
      */
     public abstract Object scrollableCursorNextObject(ObjID remoteScrollableCursorOid, ReadQuery query, DistributedSession session);

     /**
      * Retrieve previous object from the remote scrollable cursor
      */
     public abstract Object scrollableCursorPreviousObject(ObjID remoteScrollableCursorOid, ReadQuery query, DistributedSession session);

     /**
      * Moves the cursor a relative number of rows, either positive or negative.
      * Attempting to move beyond the first/last row in the result set positions the cursor before/after the
      * the first/last row
      */
     public abstract boolean scrollableCursorRelative(ObjID remoteScrollableCursorOid, int rows);

     /**
      * Return the scrollable cursor size
      */
     public abstract int scrollableCursorSize(ObjID cursorId);

     /**
      * ADVANCED:
      * This method is used to set the globally unique identifier for this connection.
      * This identifier should be the same as the JNDI context the service was stored under.
      * @param newServiceName java.lang.String
      */
     public void setServiceName(java.lang.String newServiceName) {
         serviceName = newServiceName;
     }

     /**
      * PUBLIC:
      * Release the connection resource.
      */
     public void release() {
         //no-op
     }

     /**
      * INTERNAL:
      * An object has been serialized from the server to the remote client.
      * Replace the transient attributes of the remote value holders with client-side objects.
      * Being used for the cursored stream only
      */
     public void fixObjectReferences(Transporter remoteCursoredStream, ObjectLevelReadQuery query, DistributedSession session) {
         RemoteCursoredStream stream = (RemoteCursoredStream)remoteCursoredStream.getObject();
         List<Object> remoteObjectCollection = stream.getObjectCollection();
         if (query.isReadAllQuery() && (!query.isReportQuery())) {// could be DataReadQuery
             Vector clientObjectCollection = new Vector(remoteObjectCollection.size());

             // find next power-of-2 size
             Map recursiveSet = new IdentityHashMap(remoteObjectCollection.size() + 1);
             for (Object serverSideDomainObject : remoteObjectCollection) {
                 clientObjectCollection.addElement(session.getObjectCorrespondingTo(serverSideDomainObject, remoteCursoredStream.getObjectDescriptors(), recursiveSet, query));
             }
             stream.setObjectCollection(clientObjectCollection);
         }
     }
 }
	/*
	* Copyright (c) 1998, 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:
	// Oracle - initial API and implementation from Oracle TopLink
	package org.eclipse.persistence.internal.sessions.remote;

	import java.rmi.server.ObjID;
	import java.util.IdentityHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Vector;

	import org.eclipse.persistence.descriptors.ClassDescriptor;
	import org.eclipse.persistence.queries.CursoredStreamPolicy;
	import org.eclipse.persistence.queries.DatabaseQuery;
	import org.eclipse.persistence.queries.ObjectLevelReadQuery;
	import org.eclipse.persistence.queries.ReadQuery;
	import org.eclipse.persistence.queries.ScrollableCursorPolicy;
	import org.eclipse.persistence.sessions.Login;
	import org.eclipse.persistence.sessions.remote.DistributedSession;

	/**
	* Defines set of abstract methods which one must overwrite for any kind to implement a communication mechanism.
	*/
	public abstract class RemoteConnection implements java.io.Serializable {

	/**
	* This attribute is used to provide a globally unique identifier for this connection.
	* It should be the same value as the JNDI context or the RMIRegistry context.
	*/
	protected String serviceName;

	/** Back reference to owning session. */
	protected DistributedSession session;

	/**
	* ADVANCED:
	* This method will send the command to the remote session for processing
	* @param remoteCommand Contains a command that will be executed on the remote session
	* @see org.eclipse.persistence.internal.sessions.remote.RemoteCommand
	*/
	public abstract void processCommand(RemoteCommand remoteCommand);

	/**
	* Allow the connection to initialize an setting in the session.
	*/
	public void initialize(DistributedSession session) {
	this.session = session;
	}

	public DistributedSession getSession() {
	return session;
	}

	public void setSession(DistributedSession session) {
	this.session = session;
	}

	public boolean isConnected() {
	return true;
	}

	/**
	* Begin a transaction on the database.
	*/
	public abstract void beginTransaction();

	/**
	* Begin an early unit of work transaction.
	*/
	public abstract void beginEarlyTransaction();

	/**
	* Commit remote unit of work
	*/
	public abstract RemoteUnitOfWork commitRootUnitOfWork(RemoteUnitOfWork remoteUnitOfWork);

	/**
	* Commit a transaction on the database.
	*/
	public abstract void commitTransaction();

	/**
	* Returns remote client session.
	*/
	public abstract org.eclipse.persistence.sessions.Session createRemoteSession();

	/**
	* Used for closing cursored streams across RMI.
	*/
	public abstract void cursoredStreamClose(ObjID id);

	/**
	* Retrieve next page size of objects from the remote cursored stream
	*/
	public abstract Vector cursoredStreamNextPage(RemoteCursoredStream remoteCursoredStream, ReadQuery query, DistributedSession session, int pageSize);

	/**
	* Return the cursored stream size
	*/
	public abstract int cursoredStreamSize(ObjID remoteCursoredStreamID);

	/**
	* Get remote cursor stream.
	*/
	public abstract RemoteCursoredStream cursorSelectObjects(CursoredStreamPolicy policy, DistributedSession session);

	/**
	* Get remote cursor stream.
	*/
	public abstract RemoteScrollableCursor cursorSelectObjects(ScrollableCursorPolicy policy, DistributedSession session);

	/**
	* INTERNAL:
	* Get the read-only classes
	*/
	public abstract Vector getDefaultReadOnlyClasses();

	/**
	* Get descriptor
	*/
	public abstract ClassDescriptor getDescriptor(Class<?> domainClass);

	/**
	* Get descriptor
	*/
	public abstract ClassDescriptor getDescriptorForAlias(String alias);

	/**
	* Return the login informaiton from the server.
	*/
	public abstract Login getLogin();

	/**
	* INTERNAL:
	* Perform remote function call
	*/
	public abstract Object getSequenceNumberNamed(Object remoteFunctionCall);

	/**
	* ADVANCED:
	* This method is used to get the globally unique identifier for this connection.
	* This identifier should be the same as the JNDI context the service was stored under.
	* @return java.lang.String the name
	*/
	public java.lang.String getServiceName() {
	if (serviceName == null) {
	serviceName = "";
	}
	return serviceName;
	}

	public abstract void initializeIdentityMapsOnServerSession();

	/**
	* Instantiated remote value holder.
	*/
	public abstract Transporter instantiateRemoteValueHolderOnServer(RemoteValueHolder remoteValueHolder);

	/**
	* Execute query remotely.
	*/
	public abstract Transporter remoteExecute(DatabaseQuery query);

	/**
	* Execute query remotely.
	*/
	public abstract Transporter remoteExecuteNamedQuery(String name, Class<?> javaClass, Vector arguments);

	/**
	* Rollback a transaction on the database.
	*/
	public abstract void rollbackTransaction();

	/**
	* Moves the cursor to the given row number in the result set
	*/
	public abstract boolean scrollableCursorAbsolute(ObjID remoteScrollableCursorOid, int rows);

	/**
	* Moves the cursor to the end of the result set, just after the last row.
	*/
	public abstract void scrollableCursorAfterLast(ObjID remoteScrollableCursorOid);

	/**
	* Moves the cursor to the front of the result set, just before the first row
	*/
	public abstract void scrollableCursorBeforeFirst(ObjID remoteScrollableCursorOid);

	/**
	* Used for closing scrolable cursor across RMI.
	*/
	public abstract void scrollableCursorClose(ObjID remoteScrollableCursorOid);

	/**
	* Retrieves the current row index number
	*/
	public abstract int scrollableCursorCurrentIndex(ObjID remoteScrollableCursorOid);

	/**
	* Moves the cursor to the first row in the result set
	*/
	public abstract boolean scrollableCursorFirst(ObjID remoteScrollableCursorOid);

	/**
	* Indicates whether the cursor is after the last row in the result set.
	*/
	public abstract boolean scrollableCursorIsAfterLast(ObjID remoteScrollableCursorOid);

	/**
	* Indicates whether the cursor is before the first row in the result set.
	*/
	public abstract boolean scrollableCursorIsBeforeFirst(ObjID remoteScrollableCursorOid);

	/**
	* Indicates whether the cursor is on the first row of the result set.
	*/
	public abstract boolean scrollableCursorIsFirst(ObjID remoteScrollableCursorOid);

	/**
	* Indicates whether the cursor is on the last row of the result set.
	*/
	public abstract boolean scrollableCursorIsLast(ObjID remoteScrollableCursorOid);

	/**
	* Moves the cursor to the last row in the result set
	*/
	public abstract boolean scrollableCursorLast(ObjID remoteScrollableCursorOid);

	/**
	* Retrieve next object from the remote scrollable cursor
	*/
	public abstract Object scrollableCursorNextObject(ObjID remoteScrollableCursorOid, ReadQuery query, DistributedSession session);

	/**
	* Retrieve previous object from the remote scrollable cursor
	*/
	public abstract Object scrollableCursorPreviousObject(ObjID remoteScrollableCursorOid, ReadQuery query, DistributedSession session);

	/**
	* Moves the cursor a relative number of rows, either positive or negative.
	* Attempting to move beyond the first/last row in the result set positions the cursor before/after the
	* the first/last row
	*/
	public abstract boolean scrollableCursorRelative(ObjID remoteScrollableCursorOid, int rows);

	/**
	* Return the scrollable cursor size
	*/
	public abstract int scrollableCursorSize(ObjID cursorId);

	/**
	* ADVANCED:
	* This method is used to set the globally unique identifier for this connection.
	* This identifier should be the same as the JNDI context the service was stored under.
	* @param newServiceName java.lang.String
	*/
	public void setServiceName(java.lang.String newServiceName) {
	serviceName = newServiceName;
	}

	/**
	* PUBLIC:
	* Release the connection resource.
	*/
	public void release() {
	//no-op
	}

	/**
	* INTERNAL:
	* An object has been serialized from the server to the remote client.
	* Replace the transient attributes of the remote value holders with client-side objects.
	* Being used for the cursored stream only
	*/
	public void fixObjectReferences(Transporter remoteCursoredStream, ObjectLevelReadQuery query, DistributedSession session) {
	RemoteCursoredStream stream = (RemoteCursoredStream)remoteCursoredStream.getObject();
	List<Object> remoteObjectCollection = stream.getObjectCollection();
	if (query.isReadAllQuery() && (!query.isReportQuery())) {// could be DataReadQuery
	Vector clientObjectCollection = new Vector(remoteObjectCollection.size());

	// find next power-of-2 size
	Map recursiveSet = new IdentityHashMap(remoteObjectCollection.size() + 1);
	for (Object serverSideDomainObject : remoteObjectCollection) {
	clientObjectCollection.addElement(session.getObjectCorrespondingTo(serverSideDomainObject, remoteCursoredStream.getObjectDescriptors(), recursiveSet, query));
	}
	stream.setObjectCollection(clientObjectCollection);
	}
	}
	}