foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sequencing/RemoteConnectionSequencing.java

/*
 * 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.sequencing;

import java.util.Hashtable;

import org.eclipse.persistence.internal.sessions.remote.RemoteConnection;
import org.eclipse.persistence.internal.sessions.remote.RemoteFunctionCall;
import org.eclipse.persistence.internal.sessions.remote.SequencingFunctionCall;

/*
 * RemoteConnectionSequencing class provides Sequencing through RemoteConnection.
 * It caches some info and communicates with Sequencing object
 * on its master session by sending SequencingFunctionCall objects
 * through the RemoteConnection.
 * Note that individual SequencingFunctionCalls
 * are implemented as static inner classes in SequenceFunctionCall class:
 * like SequencingFunctionCall.DoesExist.
 */
@SuppressWarnings({"rawtypes"})
class RemoteConnectionSequencing implements Sequencing {
    protected RemoteConnection remoteConnection;
    protected Hashtable classToShouldAcquireValueAfterInsert;
    protected int whenShouldAcquireValueForAll;

    public static boolean masterSequencingExists(RemoteConnection con) {
        return (Boolean) con.getSequenceNumberNamed(new SequencingFunctionCall.DoesExist());
    }

    public RemoteConnectionSequencing(RemoteConnection remoteConnection) {
        this.remoteConnection = remoteConnection;
        whenShouldAcquireValueForAll = (Integer) processFunctionCall(new SequencingFunctionCall.WhenShouldAcquireValueForAll());
        if (whenShouldAcquireValueForAll == UNDEFINED) {
            classToShouldAcquireValueAfterInsert = new Hashtable(20);
        }
    }

    @Override
    public int whenShouldAcquireValueForAll() {
        return whenShouldAcquireValueForAll;
    }

    @Override
    public Object getNextValue(Class<?> cls) {
        return processFunctionCall(new SequencingFunctionCall.GetNextValue(cls));
    }

    protected Object processFunctionCall(RemoteFunctionCall call) {
        return remoteConnection.getSequenceNumberNamed(call);
    }
}