001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.adaptive.measurements.listeners;
014    
015    import org.vmmagic.pragma.Uninterruptible;
016    
017    /**
018     * A NullListener is an object that is invoked when
019     * online measurement information must be collected.
020     *
021     * Defines update's interface.
022     */
023    
024    @Uninterruptible
025    public abstract class NullListener extends Listener {
026      /**
027       * Entry point when listener is awoken.
028       * @param whereFrom Was this a yieldpoint in a PROLOGUE, BACKEDGE, or
029       *             EPILOGUE?
030       */
031      public abstract void update(int whereFrom);
032    }