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*
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* 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).
*
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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);
}
}