/* * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package sun.management.snmp.util; import com.sun.jmx.snmp.SnmpOid; import java.io.Serializable; import java.util.Comparator;import java.util.Arrays;import java.util.TreeMap;import java.util.List;import java.util.Iterator; import java.lang.ref.WeakReference; /** * This abstract class implements a weak cache for a table whose data * is obtained from a {@link  List}. * * <p><b>NOTE: This class is not synchronized, subclasses must implement *          the appropriate synchronization whwn needed.</b></p> **/public abstract class SnmpListTableCache extends SnmpTableCache {      /**     * The index of the entry corresponding to the given <var>item</var>.     * <br>This method is called by {@link #updateCachedDatas(Object,List)}.     * The given <var>item</var> is expected to be always associated with     * the same index.     * @param context The context passed to     *        {@link #updateCachedDatas(Object,List)}.     * @param rawDatas Raw table datas passed to     *        {@link #updateCachedDatas(Object,List)}.     * @param rank Rank of the given <var>item</var> in the     *        <var>rawDatas</var> list iterator.     * @param item The raw data object for which an index must be determined.     **/    protected abstract SnmpOid getIndex(Object context, List rawDatas,                                        int rank, Object item);     /**     * The data for the entry corresponding to the given <var>item</var>.     * <br>This method is called by {@link #updateCachedDatas(Object,List)}.     * @param context The context passed to     *        {@link #updateCachedDatas(Object,List)}.     * @param rawDatas Raw table datas passed to     *        {@link #updateCachedDatas(Object,List)}.     * @param rank Rank of the given <var>item</var> in the     *        <var>rawDatas</var> list iterator.     * @param item The raw data object from which the entry data must be     *        extracted.     * @return By default <var>item</var> is returned.     **/    protected Object getData(Object context, List rawDatas,                             int rank, Object item) {        return item;    }     /**     * Recompute cached data.     * @param context A context object, valid during the duration of     *        of the call to this method, and that will be passed to     *        {@link #getIndex} and {@link #getData}. <br>     *        This method is intended to be called by     *        {@link #updateCachedDatas(Object)}. It is assumed that     *        the context is be allocated by  before this method is called,     *        and released just after this method has returned.<br>     *        This class does not use the context object: it is a simple     *        hook for subclassed.     * @param rawDatas The table datas from which the cached data will be     *        computed.     * @return the computed cached data.     **/    protected SnmpCachedData updateCachedDatas(Object context, List rawDatas) {        final int size = ((rawDatas == null)?0:rawDatas.size());        if (size == 0) return  null;         final long time = System.currentTimeMillis();        final Iterator it  = rawDatas.iterator();        final TreeMap<SnmpOid, Object> map =                new TreeMap<SnmpOid, Object>(SnmpCachedData.oidComparator);        for (int rank=0; it.hasNext() ; rank++) {            final Object  item  = it.next();            final SnmpOid index = getIndex(context, rawDatas, rank, item);            final Object  data  = getData(context, rawDatas, rank, item);            if (index == null) continue;            map.put(index,data);        }         return new SnmpCachedData(time,map);    } }