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Building blocks for ClusterMate-based services and servers.
package com.fasterxml.clustermate.service.bdb;
import java.util.concurrent.atomic.AtomicBoolean;
import com.sleepycat.je.*;
import com.fasterxml.storemate.shared.StorableKey;
import com.fasterxml.storemate.store.StoreException;
import com.fasterxml.storemate.store.backend.*;
import com.fasterxml.storemate.backend.bdbje.BDBBackendStats;
import com.fasterxml.clustermate.api.EntryKey;
import com.fasterxml.clustermate.service.LastAccessStore;
import com.fasterxml.clustermate.service.LastAccessUpdateMethod;
import com.fasterxml.clustermate.service.cfg.LastAccessConfig;
import com.fasterxml.clustermate.service.store.EntryLastAccessed;
import com.fasterxml.clustermate.service.store.StoredEntry;
import com.fasterxml.clustermate.service.store.StoredEntryConverter;
/**
* Intermediate base class for BDB-JE - backed {@link LastAccessStore}
* implementation.
*/
public abstract class BDBLastAccessStore>
extends LastAccessStore
{
/*
/**********************************************************************
/* BDB store for last-accessed timestamps
/**********************************************************************
*/
/**
* Underlying BDB entity store ("table") for last-accessed timestamps
*/
protected final Database _store;
protected final AtomicBoolean _closed = new AtomicBoolean(true);
/*
/**********************************************************************
/* Life cycle
/**********************************************************************
*/
public BDBLastAccessStore(Environment env, StoredEntryConverter conv,
LastAccessConfig config)
throws DatabaseException
{
super(conv, config);
_store = env.openDatabase(null, // no TX
"LastAccessed", dbConfig(env, config));
}
@Override
public void start() {
_closed.set(false);
}
@Override
public void prepareForStop()
{
// mark this as closed already... to help avoid cleanup task start
_closed.set(true);
// 02-May-2013, tsaloranta: Better sync() if we use deferred writes
// (otherwise not allowed to)
if (_store.getConfig().getDeferredWrite()) {
_store.sync();
}
}
@Override
public void stop() {
_store.close();
}
/*
/**********************************************************************
/* Public API, metadata
/**********************************************************************
*/
@Override
public boolean isClosed() {
return _closed.get();
}
@Override
public boolean hasEfficientEntryCount() {
// yes, BDB-JE does have this info
return true;
}
@Override
public long getEntryCount() {
return _store.count();
}
@Override
public BackendStats getEntryStatistics(BackendStatsConfig config)
{
StatsConfig statsConfig = new StatsConfig()
.setFast(config.onlyCollectFast())
.setClear(config.resetStatsAfterCollection())
;
final long start = System.currentTimeMillis();
BDBBackendStats stats = new BDBBackendStats(config, start);
stats.db = _store.getStats(statsConfig);
stats.env = _store.getEnvironment().getStats(statsConfig);
// don't accept "0 msecs" as answer :)
stats.setTimeTakenMsecs(Math.max(1L, System.currentTimeMillis() - start));
return stats;
}
/*
/**********************************************************************
/* Public API, lookups
/**********************************************************************
*/
@Override
public EntryLastAccessed findLastAccessEntry(K key, LastAccessUpdateMethod method)
{
DatabaseEntry lastAccessKey = lastAccessKey(key, method);
if (lastAccessKey == null) {
return null;
}
DatabaseEntry entry = new DatabaseEntry();
OperationStatus status = _store.get(null, lastAccessKey, entry, null);
switch (status) {
case SUCCESS:
case KEYEXIST:
return _entryConverter.createLastAccessed(entry.getData(), entry.getOffset(), entry.getSize());
case KEYEMPTY: // was deleted during operation.. shouldn't be getting
case NOTFOUND:
// fall through
}
return null;
}
/*
/**********************************************************************
/* Public API, modifications
/**********************************************************************
*/
@Override
public void updateLastAccess(E entry, long timestamp)
{
DatabaseEntry lastAccessKey = _lastAccessKey(entry);
if (lastAccessKey != null) {
/* 18-Sep-2012, tatu: Should we try to enforce constraint on monotonically
* increasing timestamps? Since this is not used for peer-to-peer syncing,
* minor deviations from exact value are ok (deletion occurs after hours,
* or at most minutes since last access), so let's avoid extra lookup.
* Same goes for other settings
*/
EntryLastAccessed acc = _entryConverter.createLastAccessed(entry, timestamp);
_store.put(null, lastAccessKey, new DatabaseEntry(acc.asBytes()));
}
}
@Override
public boolean removeLastAccess(K key, LastAccessUpdateMethod method, long timestamp) {
return _remove(lastAccessKey(key, method));
}
@Override
public boolean removeLastAccess(StorableKey rawKey) {
return _remove(BDBConverters.dbKey(rawKey));
}
protected boolean _remove(DatabaseEntry rawKey)
{
if (rawKey != null) {
OperationStatus status = _store.delete(null, rawKey);
switch (status) {
case SUCCESS:
case KEYEXIST:
return true;
default:
}
}
return false;
}
/*
/**********************************************************************
/* Public API, iteration
/**********************************************************************
*/
@Override
public IterationResult scanEntries(LastAccessIterationCallback cb)
throws StoreException
{
try {
DiskOrderedCursorConfig config = new DiskOrderedCursorConfig();
DiskOrderedCursor crsr = _store.openCursor(config);
final DatabaseEntry keyEntry = new DatabaseEntry();
final DatabaseEntry data = new DatabaseEntry();
try {
while (crsr.getNext(keyEntry, data, null) == OperationStatus.SUCCESS) {
StorableKey key = _storableKey(keyEntry);
EntryLastAccessed entry = _entryConverter.createLastAccessed(data.getData(),
data.getOffset(), data.getSize());
if (cb.processEntry(key, entry) == IterationAction.TERMINATE_ITERATION) {
return IterationResult.TERMINATED_FOR_ENTRY;
}
}
return IterationResult.FULLY_ITERATED;
} finally {
crsr.close();
}
} catch (DatabaseException de) {
return _convertDBE(null, de);
}
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
protected StorableKey _storableKey(DatabaseEntry entry) {
return new StorableKey(entry.getData(), entry.getOffset(), entry.getSize());
}
/**
* Helper method used for creating more useful exceptions for given BDB exception
*/
protected T _convertDBE(StorableKey key, DatabaseException bdbException)
throws StoreException
{
if (bdbException instanceof LockTimeoutException) {
throw new StoreException.ServerTimeout(key, bdbException);
}
throw new StoreException.Internal(key, bdbException);
}
protected DatabaseConfig dbConfig(Environment env, LastAccessConfig config)
{
DatabaseConfig dbConfig = new DatabaseConfig();
EnvironmentConfig econfig = env.getConfig();
dbConfig.setReadOnly(econfig.getReadOnly());
dbConfig.setAllowCreate(econfig.getAllowCreate());
dbConfig.setSortedDuplicates(false);
dbConfig.setDeferredWrite(config.useDeferredWrites());
return dbConfig;
}
protected DatabaseEntry _lastAccessKey(E entry) {
return lastAccessKey(entry.getKey(), entry.getLastAccessUpdateMethod());
}
protected abstract DatabaseEntry lastAccessKey(K key, LastAccessUpdateMethod acc);
}