StatementAgentInstanceFilterVersion.java

/*
 * *************************************************************************************
 *  Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 *  http://esper.codehaus.org                                                          *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 * *************************************************************************************
 */

package com.espertech.esper.core.service;

import java.io.Serializable;

/**
 * Records minimal statement filter version required for processing.
 */
public class StatementAgentInstanceFilterVersion implements Serializable {

    private static final long serialVersionUID = 5443667960162916787L;
    
    private volatile long stmtFilterVersion;

    /**
     * Ctor.
     */
    public StatementAgentInstanceFilterVersion() {
        stmtFilterVersion = Long.MIN_VALUE;
    }

    /**
     * Set filter version.
     * @param stmtFilterVersion to set
     */
    public void setStmtFilterVersion(long stmtFilterVersion) {
        this.stmtFilterVersion = stmtFilterVersion;
    }

    public long getStmtFilterVersion() {
        return stmtFilterVersion;
    }

    /**
     * Check current filter.
     * @param filterVersion to check
     * @return false if not current
     */
    public boolean isCurrentFilter(long filterVersion)
    {
        if (filterVersion < stmtFilterVersion) {
            // catch-up in case of roll
            if (filterVersion + 100000 < stmtFilterVersion) {
                stmtFilterVersion = filterVersion;
            }
            return false;
        }
        return true;
    }
}