openjpa-kernel/src/main/java/org/apache/openjpa/kernel/TimeSeededSeq.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.openjpa.kernel;

import org.apache.openjpa.meta.ClassMetaData;

////////////////////////////////////////////////////////////
// NOTE: Do not change property names; see SequenceMetaData
// for standard property names.
////////////////////////////////////////////////////////////

/**
 * A simplistic implementation of a {@link Seq} used
 * to provide datastore ids. Starts with an id equal to the system's
 * current time in milliseconds and increments from there.
 *
 * @author Greg Campbell
 */
public class TimeSeededSeq
    implements Seq {

    private long _id = System.currentTimeMillis();
    private int _increment = 1;

    @Override
    public void setType(int type) {
    }

    public int getIncrement() {
        return _increment;
    }

    public void setIncrement(int increment) {
        _increment = increment;
    }

    @Override
    public synchronized Object next(StoreContext ctx, ClassMetaData meta) {
        _id += _increment;
        return _id;
    }

    @Override
    public synchronized Object current(StoreContext ctx, ClassMetaData meta) {
        return _id;
    }

    @Override
    public void allocate(int additional, StoreContext ctx, ClassMetaData meta) {
    }

    @Override
    public void close() {
    }
}