Java from design pattern singleton to implement that is terracotta ehcache cacheManager

https://www.runoob.com/design-pattern/singleton-pattern.html#:~:text=单例模式单例模式（Singleton Pattern）是,Java 中最简单的设计模式之一。这种类型的设计模式属于创建型模式，它提供了一种创建对象的最佳方式。这种模式涉及到一个单一的类，该类负责创建自己的对象，同时确保只有单个对象被创建

public class Singleton {
private volatile static Singleton singleton;
private Singleton (){}
public static Singleton getSingleton() {
if (singleton == null) {
synchronized (Singleton.class) {
if (singleton == null) {
singleton = new Singleton();
}
}
}
return singleton;
}
}

/**

Copyright 2003-2010 Terracotta, Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package net.sf.ehcache;

import java.io.File;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeoutException;

import net.sf.ehcache.cluster.CacheCluster;
import net.sf.ehcache.cluster.ClusterScheme;
import net.sf.ehcache.cluster.ClusterSchemeNotAvailableException;
import net.sf.ehcache.cluster.NoopCacheCluster;
import net.sf.ehcache.config.CacheConfiguration;
import net.sf.ehcache.config.Configuration;
import net.sf.ehcache.config.ConfigurationFactory;
import net.sf.ehcache.config.ConfigurationHelper;
import net.sf.ehcache.config.DiskStoreConfiguration;
import net.sf.ehcache.config.FactoryConfiguration;
import net.sf.ehcache.config.InvalidConfigurationException;
import net.sf.ehcache.config.TerracottaClientConfiguration;
import net.sf.ehcache.config.TerracottaConfiguration.Consistency;
import net.sf.ehcache.config.TerracottaConfiguration.StorageStrategy;
import net.sf.ehcache.config.generator.ConfigurationUtil;
import net.sf.ehcache.constructs.nonstop.CacheManagerExecutorServiceFactory;
import net.sf.ehcache.constructs.nonstop.NonStopCacheException;
import net.sf.ehcache.constructs.nonstop.NonstopExecutorService;
import net.sf.ehcache.constructs.nonstop.NonstopExecutorServiceFactory;
import net.sf.ehcache.distribution.CacheManagerPeerListener;
import net.sf.ehcache.distribution.CacheManagerPeerProvider;
import net.sf.ehcache.event.CacheEventListener;
import net.sf.ehcache.event.CacheManagerEventListener;
import net.sf.ehcache.event.CacheManagerEventListenerRegistry;
import net.sf.ehcache.management.provider.MBeanRegistrationProvider;
import net.sf.ehcache.management.provider.MBeanRegistrationProviderException;
import net.sf.ehcache.management.provider.MBeanRegistrationProviderFactory;
import net.sf.ehcache.management.provider.MBeanRegistrationProviderFactoryImpl;
import net.sf.ehcache.store.DiskStore;
import net.sf.ehcache.store.Store;
import net.sf.ehcache.terracotta.ClusteredInstanceFactory;
import net.sf.ehcache.terracotta.TerracottaClient;
import net.sf.ehcache.terracotta.TerracottaClientRejoinListener;
import net.sf.ehcache.transaction.ReadCommittedSoftLockFactoryImpl;
import net.sf.ehcache.transaction.SoftLockFactory;
import net.sf.ehcache.transaction.TransactionIDFactory;
import net.sf.ehcache.transaction.TransactionIDFactoryImpl;
import net.sf.ehcache.transaction.manager.TransactionManagerLookup;
import net.sf.ehcache.transaction.xa.processor.XARequestProcessor;
import net.sf.ehcache.util.FailSafeTimer;
import net.sf.ehcache.util.PropertyUtil;
import net.sf.ehcache.util.UpdateChecker;
import net.sf.ehcache.writer.writebehind.WriteBehind;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**

A container for {@link Ehcache}s that maintain all aspects of their lifecycle.
CacheManager may be either be a singleton if created with factory methods, or multiple instances may exist, in which case resources
required by each must be unique.
A CacheManager holds references to Caches and Ehcaches and manages their creation and lifecycle.
@author Greg Luck
@version $Id: CacheManager.java 4187 2011-06-27 11:46:16Z asingh $
*/
public class CacheManager {

/**
- Default name if not specified in the configuration/
  */
  public static final String DEFAULT_NAME = "DEFAULT";
/**
- Keeps track of all known CacheManagers. Used to check on conflicts.
- CacheManagers should remove themselves from this list during shut down.
  */
  public static final List ALL_CACHE_MANAGERS = new CopyOnWriteArrayList();
/**
- System property to enable creation of a shutdown hook for CacheManager.
  */
  public static final String ENABLE_SHUTDOWN_HOOK_PROPERTY = "net.sf.ehcache.enableShutdownHook";
private static final Logger LOG = LoggerFactory.getLogger(CacheManager.class);

/**
- Update check interval - one week in milliseconds
  */
  private static final long EVERY_WEEK = 7 * 24 * 60 * 60 * 1000;
/**
- delay period before doing update check
  */
  private static final long DELAY_UPDATE_CHECK = 1000;
/**
- The Singleton Instance.
  */
  private static volatile CacheManager singleton;
/**
- The factory to use for creating MBeanRegistrationProvider's
  */
  private static final MBeanRegistrationProviderFactory MBEAN_REGISTRATION_PROVIDER_FACTORY = new MBeanRegistrationProviderFactoryImpl();
private static final String NO_DEFAULT_CACHE_ERROR_MSG = "Caches cannot be added by name when default cache config is not specified"
+ " in the config. Please add a default cache config in the configuration.";

/**
- A name for this CacheManager to distinguish it from others.
  */
  protected volatile String name;
/**
- Status of the Cache Manager
  */
  protected volatile Status status;
/**
- The map of providers
  */
  protected final Map<String, CacheManagerPeerProvider> cacheManagerPeerProviders = new ConcurrentHashMap<String, CacheManagerPeerProvider>();
/**
- The map of listeners
  */
  protected final Map<String, CacheManagerPeerListener> cacheManagerPeerListeners = new ConcurrentHashMap<String, CacheManagerPeerListener>();
/**
- The listener registry
  */
  protected final CacheManagerEventListenerRegistry cacheManagerEventListenerRegistry = new CacheManagerEventListenerRegistry();
/**
- The shutdown hook thread for CacheManager. This ensures that the CacheManager and Caches are left in a
- consistent state on a CTRL-C or kill.
- This thread must be unregistered as a shutdown hook, when the CacheManager is disposed. Otherwise the CacheManager is not GC-able.
- Of course kill -9 or abrupt termination will not run the shutdown hook. In this case, various sanity checks are made at start up.
  */
  protected Thread shutdownHook;
/**
- Ehcaches managed by this manager.
  */
  private final ConcurrentMap<String, Ehcache> ehcaches = new ConcurrentHashMap<String, Ehcache>();
/**
- Default cache cache.
  */
  private Ehcache defaultCache;
/**
- The path for the directory in which disk caches are created.
  */
  private String diskStorePath;
private MBeanRegistrationProvider mbeanRegistrationProvider;

private FailSafeTimer cacheManagerTimer;

private volatile TerracottaClient terracottaClient;

/**
- The {@link TerracottaClientConfiguration} used for this {@link CacheManager}
  */
  private TerracottaClientConfiguration terracottaClientConfiguration;
private Configuration configuration;

private volatile boolean allowsDynamicCacheConfig = true;

private volatile TransactionManagerLookup transactionManagerLookup;

private volatile TransactionController transactionController;

private final ConcurrentMap<String, SoftLockFactory> softLockFactories = new ConcurrentHashMap<String, SoftLockFactory>();

private final NonstopExecutorServiceFactory nonstopExecutorServiceFactory = CacheManagerExecutorServiceFactory.getInstance();

/**
- An constructor for CacheManager, which takes a configuration object, rather than one created by parsing
- an ehcache.xml file. This constructor gives complete control over the creation of the CacheManager.
- Care should be taken to ensure that, if multiple CacheManages are created, they do now overwrite each others disk store files, as
- would happend if two were created which used the same diskStore path.
- This method does not act as a singleton. Callers must maintain their own reference to it.
- Note that if one of the {@link #create()} methods are called, a new singleton instance will be created, separate from any instances
- created in this method.
- @param configuration
- @throws CacheException
  */
  public CacheManager(Configuration configuration) throws CacheException {
  status = Status.STATUS_UNINITIALISED;
  init(configuration, null, null, null);
  }
/**
- An ordinary constructor for CacheManager.
- This method does not act as a singleton. Callers must maintain a reference to it.
- Note that if one of the {@link #create()} methods are called, a new singleton will be created,
- separate from any instances created in this method.
- @param configurationFileName
- ```
       an xml configuration file available through a file name. The configuration {@link File} is created
```
- ```
       using new <code>File(configurationFileName)</code>
```
- @throws CacheException
- @see #create(String)
  */
  public CacheManager(String configurationFileName) throws CacheException {
  status = Status.STATUS_UNINITIALISED;
  init(null, configurationFileName, null, null);
  }
/**
- An ordinary constructor for CacheManager.
- This method does not act as a singleton. Callers must maintain a reference to it.
- Note that if one of the {@link #create()} methods are called, a new singleton will be created,
- separate from any instances created in this method.
- This method can be used to specify a configuration resource in the classpath other than the default of "/ehcache.xml":
- URL url = this.getClass().getResource("/ehcache-2.xml");
- Note that {@link Class#getResource} will look for resources in the same package unless a leading "/" is used, in which case it will
- look in the root of the classpath.
- You can also load a resource using other class loaders. e.g.
- @param configurationURL
- ```
       an xml configuration available through a URL.
```
- @throws CacheException
- @see #create(java.net.URL)
- @since 1.2
  */
  public CacheManager(URL configurationURL) throws CacheException {
  status = Status.STATUS_UNINITIALISED;
  init(null, null, configurationURL, null);
  }
/**
- An ordinary constructor for CacheManager.
- This method does not act as a singleton. Callers must maintain a reference to it.
- Note that if one of the {@link #create()} methods are called, a new singleton will be created,
- separate from any instances created in this method.
- @param configurationInputStream
- ```
       an xml configuration file available through an inputstream
```
- @throws CacheException
- @see #create(java.io.InputStream)
  */
  public CacheManager(InputStream configurationInputStream) throws CacheException {
  status = Status.STATUS_UNINITIALISED;
  init(null, null, null, configurationInputStream);
  }
/**
- Constructor.
- @throws CacheException
  */
  public CacheManager() throws CacheException {
  // default config will be done
  status = Status.STATUS_UNINITIALISED;
  init(null, null, null, null);
  }
/**
- initialises the CacheManager
  */
  protected void init(Configuration initialConfiguration, String configurationFileName, URL configurationURL,
  InputStream configurationInputStream) {
  Configuration localConfiguration = initialConfiguration;
  if (initialConfiguration == null) {
  localConfiguration = parseConfiguration(configurationFileName, configurationURL, configurationInputStream);
  this.configuration = localConfiguration;
  } else {
  this.configuration = initialConfiguration;
  }
  
  if (this.configuration.getTerracottaConfiguration() != null) {
  this.configuration.getTerracottaConfiguration().freezeConfig();
  }
  validateConfiguration();
  
  if (localConfiguration.getName() != null) {
  this.name = localConfiguration.getName();
  }
  
  this.allowsDynamicCacheConfig = localConfiguration.getDynamicConfig();
  this.terracottaClientConfiguration = localConfiguration.getTerracottaConfiguration();
  
  terracottaClient = new TerracottaClient(this, new TerracottaClientRejoinListener() {
  public void clusterRejoinStarted() {
  CacheManager.this.clusterRejoinStarted();
  }
```
 public void clusterRejoinComplete() {
     CacheManager.this.clusterRejoinComplete();
 }
```
  }, localConfiguration.getTerracottaConfiguration());
  
  Map<String, CacheConfiguration> cacheConfigs = localConfiguration.getCacheConfigurations();
  if (localConfiguration.getDefaultCacheConfiguration() != null
  && localConfiguration.getDefaultCacheConfiguration().isTerracottaClustered()) {
  terracottaClient.createClusteredInstanceFactory(cacheConfigs);
  } else {
  for (CacheConfiguration config : cacheConfigs.values()) {
  if (config.isTerracottaClustered()) {
  terracottaClient.createClusteredInstanceFactory(cacheConfigs);
  break;
  }
  }
  }
  
  if (terracottaClient.getClusteredInstanceFactory() != null && this.name == null) {
  this.name = CacheManager.DEFAULT_NAME;
  }
  
  TransactionIDFactory transactionIDFactory = createTransactionIDFactory();
  this.transactionController = new TransactionController(transactionIDFactory, configuration.getDefaultTransactionTimeoutInSeconds());
  
  ConfigurationHelper configurationHelper = new ConfigurationHelper(this, localConfiguration);
  configure(configurationHelper);
  status = Status.STATUS_ALIVE;
  
  for (CacheManagerPeerProvider cacheManagerPeerProvider : cacheManagerPeerProviders.values()) {
  cacheManagerPeerProvider.init();
  }
  
  cacheManagerEventListenerRegistry.init();
  addShutdownHookIfRequired();
  
  cacheManagerTimer = new FailSafeTimer(getName());
  checkForUpdateIfNeeded(localConfiguration.getUpdateCheck());
  
  mbeanRegistrationProvider = MBEAN_REGISTRATION_PROVIDER_FACTORY.createMBeanRegistrationProvider(localConfiguration);
  
  // do this last
  addConfiguredCaches(configurationHelper);
  
  try {
  mbeanRegistrationProvider.initialize(this, terracottaClient.getClusteredInstanceFactory());
  } catch (MBeanRegistrationProviderException e) {
  LOG.warn("Failed to initialize the MBeanRegistrationProvider - " + mbeanRegistrationProvider.getClass().getName(), e);
  }
  }
private boolean isTerracottaRejoinEnabled() {
TerracottaClientConfiguration terracottaConfiguration = configuration.getTerracottaConfiguration();
return terracottaConfiguration != null && terracottaConfiguration.isRejoin();
}

private void validateConfiguration() {
if (isTerracottaRejoinEnabled()) {
validateCacheConfigs(configuration.getCacheConfigurations().values());
}
}

private void validateCacheConfigs(Collection cacheConfigs) {
boolean invalid = false;
final StringBuilder error = new StringBuilder();
final List invalidCaches = new ArrayList();
for (CacheConfiguration config : cacheConfigs) {
if (config.isTerracottaClustered()) {
if (config.getTerracottaConfiguration().getStorageStrategy().equals(StorageStrategy.CLASSIC)) {
if (config.getTerracottaConfiguration().isNonstopEnabled()) {
invalid = true;
error.append("\n").append(
"NONSTOP can't be enabled with " + StorageStrategy.CLASSIC.name() + " strategy. Invalid Cache: "
+ config.getName());
}
```
             if (isTerracottaRejoinEnabled()) {
                 invalid = true;
                 error.append("\n").append(
                         "REJOIN can't be enabled with " + StorageStrategy.CLASSIC.name() + " strategy. Invalid Cache: "
                                 + config.getName());
             }

             if (config.getTerracottaConsistency().equals(Consistency.EVENTUAL)) {
                 invalid = true;
                 error.append("\n").append(
                         Consistency.EVENTUAL.name() + " consistency can't be enabled with " + StorageStrategy.CLASSIC.name()
                                 + " strategy. Invalid Cache: " + config.getName());
             }
         }

         if (isTerracottaRejoinEnabled() && !config.getTerracottaConfiguration().isNonstopEnabled()) {
             invalid = true;
             error.append("\n").append(
                     "Terracotta clustered caches must be nonstop when rejoin is enabled. Invalid cache: " + config.getName());
         }
     }
 }

 if (invalid) {
     String errorMessage = "Errors:" + error.toString();
     throw new InvalidConfigurationException(errorMessage);
 }
```
}

/**
- Returns unique cluster-wide id for this cache-manager. Only applicable when running in "cluster" mode, e.g. when this cache-manager
- contains caches clustered with Terracotta. Otherwise returns blank string.
- @return Returns unique cluster-wide id for this cache-manager when it contains clustered caches (e.g. Terracotta clustered caches).
- ```
    Otherwise returns blank string.
```
*/
public String getClusterUUID() {
if (terracottaClient.getClusteredInstanceFactory() != null) {
return getClientUUID(terracottaClient.getClusteredInstanceFactory());
} else {
return "";
}
}

private static String getClientUUID(ClusteredInstanceFactory clusteredInstanceFactory) {
return clusteredInstanceFactory.getUUID();
}

/**
- Create/access the appropriate terracotta clustered store for the given cache
- @param cache The cache for which the Store should be created
- @return a new (or existing) clustered store
  */
  public Store createTerracottaStore(Ehcache cache) {
  return getClusteredInstanceFactory(cache).createStore(cache);
  }
/**
- Create/access the appropriate clustered write behind queue for the given cache
- @param cache The cache for which the write behind queue should be created
- @return a new (or existing) write behind queue
  */
  public WriteBehind createTerracottaWriteBehind(Ehcache cache) {
  return getClusteredInstanceFactory(cache).createWriteBehind(cache);
  }
/**
- Create/access the appropriate clustered cache event replicator for the given cache
- @param cache The cache for which the clustered event replicator should be created
- @return a new cache event replicator
  */
  public CacheEventListener createTerracottaEventReplicator(Ehcache cache) {
  return getClusteredInstanceFactory(cache).createEventReplicator(cache);
  }
/**
- Return the clustered instance factory for a cache of this cache manager.
- @param cache the cache the clustered instance factory has to be returned for
- @return the clustered instance factory
  */
  private ClusteredInstanceFactory getClusteredInstanceFactory(Ehcache cache) {
  ClusteredInstanceFactory clusteredInstanceFactory = terracottaClient.getClusteredInstanceFactory();
  if (null == clusteredInstanceFactory) {
  // adding a cache programmatically when there is no clustered store defined in the configuration
  // at the time this cacheManager was created
  Map<String, CacheConfiguration> map = new HashMap<String, CacheConfiguration>(1);
  map.put(cache.getName(), cache.getCacheConfiguration());
  final boolean created = terracottaClient.createClusteredInstanceFactory(map);
  clusteredInstanceFactory = terracottaClient.getClusteredInstanceFactory();
```
 if (created) {
     try {
         mbeanRegistrationProvider.reinitialize(clusteredInstanceFactory);
     } catch (MBeanRegistrationProviderException e) {
         LOG.warn("Failed to initialize the MBeanRegistrationProvider - " + mbeanRegistrationProvider.getClass().getName(), e);
     }
 }
```
  }
  return clusteredInstanceFactory;
  }
private void checkForUpdateIfNeeded(boolean updateCheckNeeded) {
try {
if (updateCheckNeeded) {
UpdateChecker updateChecker = new UpdateChecker();
cacheManagerTimer.scheduleAtFixedRate(updateChecker, DELAY_UPDATE_CHECK, EVERY_WEEK);
}
} catch (Throwable t) {
LOG.debug("Failed to set up update checker", t);
}
}

/**
- Loads configuration, either from the supplied {@link ConfigurationHelper} or by creating a new Configuration instance
- from the configuration file referred to by file, inputstream or URL.
- Should only be called once.
- @param configurationFileName
- ```
       the file name to parse, or null
```
- @param configurationURL
- ```
       the URL to pass, or null
```
- @param configurationInputStream
- ```
       , the InputStream to parse, or null
```
- @return the loaded configuration
- @throws CacheException
- ```
        if the configuration cannot be parsed
```
*/
private synchronized Configuration parseConfiguration(String configurationFileName, URL configurationURL,
InputStream configurationInputStream) throws CacheException {
reinitialisationCheck();
Configuration parsedConfig;
if (configurationFileName != null) {
```
     LOG.debug("Configuring CacheManager from {}", configurationFileName);
     parsedConfig = ConfigurationFactory.parseConfiguration(new File(configurationFileName));
 } else if (configurationURL != null) {
     parsedConfig = ConfigurationFactory.parseConfiguration(configurationURL);
 } else if (configurationInputStream != null) {
     parsedConfig = ConfigurationFactory.parseConfiguration(configurationInputStream);
 } else {
     LOG.debug("Configuring ehcache from classpath.");
     parsedConfig = ConfigurationFactory.parseConfiguration();
 }
 return parsedConfig;
```
}

private void configure(ConfigurationHelper configurationHelper) {
```
 diskStorePath = configurationHelper.getDiskStorePath();
 int cachesRequiringDiskStores = configurationHelper.numberOfCachesThatOverflowToDisk().intValue()
         + configurationHelper.numberOfCachesThatAreDiskPersistent().intValue();

 if (diskStorePath == null && cachesRequiringDiskStores > 0) {
     diskStorePath = DiskStoreConfiguration.getDefaultPath();
     LOG.warn("One or more caches require a DiskStore but there is no diskStore element configured."
             + " Using the default disk store path of " + DiskStoreConfiguration.getDefaultPath()
             + ". Please explicitly configure the diskStore element in ehcache.xml.");
 }

 FactoryConfiguration lookupConfiguration = configuration.getTransactionManagerLookupConfiguration();
 try {
     Properties properties = PropertyUtil.parseProperties(lookupConfiguration.getProperties(), lookupConfiguration
             .getPropertySeparator());
     Class<TransactionManagerLookup> transactionManagerLookupClass = (Class<TransactionManagerLookup>) Class
             .forName(lookupConfiguration.getFullyQualifiedClassPath());
     this.transactionManagerLookup = transactionManagerLookupClass.newInstance();
     this.transactionManagerLookup.setProperties(properties);
 } catch (Exception e) {
     LOG.error("could not instantiate transaction manager lookup class: {}", lookupConfiguration.getFullyQualifiedClassPath(), e);
 }

 detectAndFixDiskStorePathConflict(configurationHelper);

 cacheManagerEventListenerRegistry.registerListener(configurationHelper.createCacheManagerEventListener());

 cacheManagerPeerListeners.putAll(configurationHelper.createCachePeerListeners());
 for (CacheManagerPeerListener cacheManagerPeerListener : cacheManagerPeerListeners.values()) {
     cacheManagerEventListenerRegistry.registerListener(cacheManagerPeerListener);
 }

 detectAndFixCacheManagerPeerListenerConflict(configurationHelper);

 ALL_CACHE_MANAGERS.add(this);

 cacheManagerPeerProviders.putAll(configurationHelper.createCachePeerProviders());
 defaultCache = configurationHelper.createDefaultCache();
```
}

private void detectAndFixDiskStorePathConflict(ConfigurationHelper configurationHelper) {
if (diskStorePath == null) {
LOG.debug("No disk store path defined. Skipping disk store path conflict test.");
return;
}
```
 for (CacheManager cacheManager : ALL_CACHE_MANAGERS) {
     if (diskStorePath.equals(cacheManager.diskStorePath)) {
         String newDiskStorePath = diskStorePath + File.separator + DiskStore.generateUniqueDirectory();
         LOG.warn("Creating a new instance of CacheManager using the diskStorePath \"" + diskStorePath + "\" which is already used"
                 + " by an existing CacheManager.\nThe source of the configuration was "
                 + configurationHelper.getConfigurationBean().getConfigurationSource() + ".\n"
                 + "The diskStore path for this CacheManager will be set to " + newDiskStorePath + ".\nTo avoid this"
                 + " warning consider using the CacheManager factory methods to create a singleton CacheManager "
                 + "or specifying a separate ehcache configuration (ehcache.xml) for each CacheManager instance.");
         diskStorePath = newDiskStorePath;
         break;
     }
 }
```
}

private void detectAndFixCacheManagerPeerListenerConflict(ConfigurationHelper configurationHelper) {
if (cacheManagerPeerListeners == null) {
return;
}
for (CacheManagerPeerListener cacheManagerPeerListener : cacheManagerPeerListeners.values()) {
String uniqueResourceIdentifier = cacheManagerPeerListener.getUniqueResourceIdentifier();
for (CacheManager cacheManager : ALL_CACHE_MANAGERS) {
for (CacheManagerPeerListener otherCacheManagerPeerListener : cacheManager.cacheManagerPeerListeners.values()) {
if (otherCacheManagerPeerListener == null) {
continue;
}
String otherUniqueResourceIdentifier = otherCacheManagerPeerListener.getUniqueResourceIdentifier();
if (uniqueResourceIdentifier.equals(otherUniqueResourceIdentifier)) {
LOG.warn("Creating a new instance of CacheManager with a CacheManagerPeerListener which "
+ "has a conflict on a resource that must be unique.\n" + "The resource is " + uniqueResourceIdentifier
+ ".\n" + "Attempting automatic resolution. The source of the configuration was "
+ configurationHelper.getConfigurationBean().getConfigurationSource() + ".\n"
+ "To avoid this warning consider using the CacheManager factory methods to create a "
+ "singleton CacheManager "
+ "or specifying a separate ehcache configuration (ehcache.xml) for each CacheManager instance.");
cacheManagerPeerListener.attemptResolutionOfUniqueResourceConflict();
break;
}
}
```
     }
 }
```
}

private void addConfiguredCaches(ConfigurationHelper configurationHelper) {
Set unitialisedCaches = configurationHelper.createCaches();
for (Iterator iterator = unitialisedCaches.iterator(); iterator.hasNext()😉 {
Ehcache unitialisedCache = (Ehcache) iterator.next();
addCacheNoCheck(unitialisedCache, true);
```
     // add the cache decorators for the cache, if any
     List<Ehcache> cacheDecorators = configurationHelper.createCacheDecorators(unitialisedCache);
     for (Ehcache decoratedCache : cacheDecorators) {
         addOrReplaceDecoratedCache(unitialisedCache, decoratedCache);
     }
 }
```
}

private void addOrReplaceDecoratedCache(final Ehcache underlyingCache, final Ehcache decoratedCache) {
if (decoratedCache.getName().equals(underlyingCache.getName())) {
this.replaceCacheWithDecoratedCache(underlyingCache, decoratedCache);
} else {
addDecoratedCache(decoratedCache);
}
}

private void reinitialisationCheck() throws IllegalStateException {
if (diskStorePath != null || ehcaches.size() != 0 || status.equals(Status.STATUS_SHUTDOWN)) {
throw new IllegalStateException("Attempt to reinitialise the CacheManager");
}
}

/**
- A factory method to create a singleton CacheManager with default config, or return it if it exists.
- The configuration will be read, {@link Ehcache}s created and required stores initialized. When the {@link CacheManager} is no longer
- required, call shutdown to free resources.
- @return the singleton CacheManager
- @throws CacheException
- ```
        if the CacheManager cannot be created
```
*/
public static CacheManager create() throws CacheException {
if (singleton != null) {
return singleton;
}
synchronized (CacheManager.class) {
if (singleton == null) {
LOG.debug("Creating new CacheManager with default config");
singleton = new CacheManager();
} else {
LOG.debug("Attempting to create an existing singleton. Existing singleton returned.");
}
return singleton;
}
}

/**
- A factory method to create a singleton CacheManager with default config, or return it if it exists.
- This has the same effect as
- Same as
- @return the singleton CacheManager
- @throws CacheException
- ```
        if the CacheManager cannot be created
```
*/
public static CacheManager getInstance() throws CacheException {
return CacheManager.create();
}

/**
- A factory method to create a singleton CacheManager with a specified configuration.
- @param configurationFileName
- ```
       an xml file compliant with the ehcache.xsd schema
```
- ```
       <p/>
```
- ```
       The configuration will be read, {@link Ehcache}s created and required stores initialized. When the {@link CacheManager} is
```
- ```
       no longer required, call shutdown to free resources.
```
*/
public static CacheManager create(String configurationFileName) throws CacheException {
if (singleton != null) {
return singleton;
}
synchronized (CacheManager.class) {
if (singleton == null) {
LOG.debug("Creating new CacheManager with config file: {}", configurationFileName);
singleton = new CacheManager(configurationFileName);
}
return singleton;
}
}

/**
- A factory method to create a singleton CacheManager from an URL.
- This method can be used to specify a configuration resource in the classpath other than the default of "/ehcache.xml": This method
- can be used to specify a configuration resource in the classpath other than the default of "/ehcache.xml":
- URL url = this.getClass().getResource("/ehcache-2.xml");
- Note that {@link Class#getResource} will look for resources in the same package unless a leading "/" is used, in which case it will
- look in the root of the classpath.
- You can also load a resource using other class loaders. e.g.
- @param configurationFileURL
- ```
       an URL to an xml file compliant with the ehcache.xsd schema
```
- ```
       <p/>
```
- ```
       The configuration will be read, {@link Ehcache}s created and required stores initialized. When the {@link CacheManager} is
```
- ```
       no longer required, call shutdown to free resources.
```
*/
public static CacheManager create(URL configurationFileURL) throws CacheException {
if (singleton != null) {
return singleton;
}
synchronized (CacheManager.class) {
if (singleton == null) {
LOG.debug("Creating new CacheManager with config URL: {}", configurationFileURL);
singleton = new CacheManager(configurationFileURL);
}
return singleton;
}
}

/**
- A factory method to create a singleton CacheManager from a java.io.InputStream.
- This method makes it possible to use an inputstream for configuration. Note: it is the clients responsibility to close the
- inputstream.
- @param inputStream
- ```
       InputStream of xml compliant with the ehcache.xsd schema
```
- ```
       <p/>
```
- ```
       The configuration will be read, {@link Ehcache}s created and required stores initialized. When the {@link CacheManager} is
```
- ```
       no longer required, call shutdown to free resources.
```
*/
public static CacheManager create(InputStream inputStream) throws CacheException {
if (singleton != null) {
return singleton;
}
synchronized (CacheManager.class) {
if (singleton == null) {
LOG.debug("Creating new CacheManager with InputStream");
singleton = new CacheManager(inputStream);
}
return singleton;
}
}

/**
- A factory method to create a singleton CacheManager from a net.sf.ehcache.config.Configuration.
- This method makes it possible to use an inputstream for configuration. Note: it is the clients responsibility to close the
- inputstream.
- @param config
  */
  public static CacheManager create(Configuration config) throws CacheException {
  if (singleton != null) {
  return singleton;
  }
  synchronized (CacheManager.class) {
  if (singleton == null) {
  LOG.debug("Creating new CacheManager with InputStream");
  singleton = new CacheManager(config);
  }
  return singleton;
  }
  }
/**
- Returns a concrete implementation of Cache, it it is available in the CacheManager.
- Consider using getEhcache(String name) instead, which will return decorated caches that are registered.
- If a decorated ehcache is registered in CacheManager, an undecorated Cache with the same name may also exist.
- Since version ehcache-core-2.1.0, when an {@link Ehcache} decorator is present in the CacheManager, its not necessary that a
- {@link Cache} instance is also present for the same name. Decorators can have different names other than the name of the cache its
- decorating.
- @return a Cache, if an object of that type exists by that name, else null
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_ALIVE}
```
- @see #getEhcache(String)
  */
  public Cache getCache(String name) throws IllegalStateException, ClassCastException {
  checkStatus();
  return ehcaches.get(name) instanceof Cache ? (Cache) ehcaches.get(name) : null;
  }
/**
- Gets an Ehcache
- @return a Cache, if an object of type Cache exists by that name, else null
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_ALIVE}
```
*/
public Ehcache getEhcache(String name) throws IllegalStateException {
checkStatus();
return ehcaches.get(name);
}

/**
- Some caches might be persistent, so we want to add a shutdown hook if that is the
- case, so that the data and index can be written to disk.
  */
  private void addShutdownHookIfRequired() {
  
  String shutdownHookProperty = System.getProperty(ENABLE_SHUTDOWN_HOOK_PROPERTY);
  boolean enabled = PropertyUtil.parseBoolean(shutdownHookProperty);
  if (!enabled) {
  return;
  } else {
  LOG.info("The CacheManager shutdown hook is enabled because {} is set to true.", ENABLE_SHUTDOWN_HOOK_PROPERTY);
```
 Thread localShutdownHook = new Thread() {
     @Override
     public void run() {
         synchronized (this) {
             if (status.equals(Status.STATUS_ALIVE)) {
                 // clear shutdown hook reference to prevent
                 // removeShutdownHook to remove it during shutdown
                 shutdownHook = null;
                 LOG.info("VM shutting down with the CacheManager still active. Calling shutdown.");
                 shutdown();
             }
         }
     }
 };

 Runtime.getRuntime().addShutdownHook(localShutdownHook);
 shutdownHook = localShutdownHook;
```
  }
  }
/**
- Remove the shutdown hook to prevent leaving orphaned CacheManagers around. This
- is called by {@link #shutdown()} AFTER the status has been set to shutdown.
  */
  private void removeShutdownHook() {
  if (shutdownHook != null) {
  // remove shutdown hook
  try {
  Runtime.getRuntime().removeShutdownHook(shutdownHook);
  } catch (IllegalStateException e) {
  // This will be thrown if the VM is shutting down. In this case
  // we do not need to worry about leaving references to CacheManagers lying
  // around and the call is ok to fail.
  LOG.debug("IllegalStateException due to attempt to remove a shutdown" + "hook while the VM is actually shutting down.", e);
  }
  shutdownHook = null;
  }
  }
/**
- Adds a {@link Ehcache} based on the defaultCache with the given name.
- Memory and Disk stores will be configured for it and it will be added to the map of caches.
- Also notifies the CacheManagerEventListener after the cache was initialised and added.
- It will be created with the defaultCache attributes specified in ehcache.xml
- @param cacheName
- ```
       the name for the cache
```
- @throws ObjectExistsException
- ```
        if the cache already exists
```
- @throws CacheException
- ```
        if there was an error creating the cache.
```
*/
public void addCache(String cacheName) throws IllegalStateException, ObjectExistsException, CacheException {
checkStatus();
```
 // NPE guard
 if (cacheName == null || cacheName.length() == 0) {
     return;
 }

 if (ehcaches.get(cacheName) != null) {
     throw new ObjectExistsException("Cache " + cacheName + " already exists");
 }
 Ehcache clonedDefaultCache = cloneDefaultCache(cacheName);
 if (clonedDefaultCache == null) {
     throw new CacheException(NO_DEFAULT_CACHE_ERROR_MSG);
 }
 addCache(clonedDefaultCache);
 for (Ehcache ehcache : createDefaultCacheDecorators(clonedDefaultCache)) {
     addOrReplaceDecoratedCache(clonedDefaultCache, ehcache);
 }
```
}

/**
- Adds a {@link Cache} to the CacheManager.
- Memory and Disk stores will be configured for it and it will be added to the map of caches. Also notifies the
- CacheManagerEventListener after the cache was initialised and added.
- @param cache
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_UNINITIALISED} before this method is called.
```
- @throws ObjectExistsException
- ```
        if the cache already exists in the CacheManager
```
- @throws CacheException
- ```
        if there was an error adding the cache to the CacheManager
```
*/
public void addCache(Cache cache) throws IllegalStateException, ObjectExistsException, CacheException {
checkStatus();
if (cache == null) {
return;
}
addCache((Ehcache) cache);
}

/**
- Adds an {@link Ehcache} to the CacheManager.
- Memory and Disk stores will be configured for it and it will be added to the map of caches. Also notifies the
- CacheManagerEventListener after the cache was initialised and added.
- @param cache
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_UNINITIALISED} before this method is called.
```
- @throws ObjectExistsException
- ```
        if the cache already exists in the CacheManager
```
- @throws CacheException
- ```
        if there was an error adding the cache to the CacheManager
```
*/
public void addCache(Ehcache cache) throws IllegalStateException, ObjectExistsException, CacheException {
checkStatus();
if (cache == null) {
return;
}
addCacheNoCheck(cache, true);
}

/**
- Adds a decorated {@link Ehcache} to the CacheManager. This method neither creates the memory/disk store
- nor initializes the cache. It only adds the cache reference to the map of caches held by this
- cacheManager.
- It is generally required that a decorated cache, once constructed, is made available to other execution threads. The simplest way of
- doing this is to either add it to the cacheManager with a different name or substitute the original cache with the decorated one.
- This method adds the decorated cache assuming it has a different name. If another cache (decorated or not) with the same name already
- exists, it will throw {@link ObjectExistsException}. For replacing existing cache with another decorated cache having same name,
- please use
- Note that any overridden Ehcache methods by the decorator will take on new behaviours without casting. Casting is only required for
- new methods that the decorator introduces. For more information see the well known Gang of Four Decorator pattern.
- @param decoratedCache
- @throws ObjectExistsException
- ```
        if another cache with the same name already exists.
```
*/
public void addDecoratedCache(Ehcache decoratedCache) throws ObjectExistsException {
internalAddDecoratedCache(decoratedCache, true);
}

/**
- Same as {@link #addDecoratedCache(Ehcache)} but does not throw exception if another cache with same name already exists.
- @param decoratedCache
- @throws ObjectExistsException
  */
  public void addDecoratedCacheIfAbsent(Ehcache decoratedCache) throws ObjectExistsException {
  internalAddDecoratedCache(decoratedCache, false);
  }
private void internalAddDecoratedCache(final Ehcache decoratedCache, final boolean strict) {
Ehcache old = ehcaches.putIfAbsent(decoratedCache.getName(), decoratedCache);
if (strict && old != null) {
throw new ObjectExistsException("Cache " + decoratedCache.getName() + " already exists in the CacheManager");
}
}

private Ehcache addCacheNoCheck(final Ehcache cache, final boolean strict) throws IllegalStateException, ObjectExistsException,
CacheException {
```
 if (isTerracottaRejoinEnabled()) {
     validateCacheConfigs(Collections.singletonList(cache.getCacheConfiguration()));
 }

 if (cache.getStatus() != Status.STATUS_UNINITIALISED) {
     throw new CacheException("Trying to add an already initialized cache." + " If you are adding a decorated cache, "
             + "use CacheManager.addDecoratedCache" + "(Ehcache decoratedCache) instead.");
 }

 Ehcache ehcache = ehcaches.get(cache.getName());
 if (ehcache != null) {
     if (strict) {
         throw new ObjectExistsException("Cache " + cache.getName() + " already exists");
     } else {
         return ehcache;
     }
 }
 cache.setCacheManager(this);
 if (cache.getCacheConfiguration().getDiskStorePath() == null) {
     cache.setDiskStorePath(diskStorePath);
 }
 cache.setTransactionManagerLookup(transactionManagerLookup);

 Map<String, CacheConfiguration> configMap = configuration.getCacheConfigurations();
 if (!configMap.containsKey(cache.getName())) {
     CacheConfiguration cacheConfig = cache.getCacheConfiguration();
     if (cacheConfig != null) {
         configuration.addCache(cacheConfig);
     }
 }

 if (isTerracottaRejoinEnabled() && cache.getCacheConfiguration().isTerracottaClustered()) {
     final long timeoutMillis = cache.getCacheConfiguration().getTerracottaConfiguration().getNonstopConfiguration()
             .getTimeoutMillis();
     try {
         getNonstopExecutorService().execute(new Callable<Void>() {
             public Void call() throws Exception {
                 cache.initialise();
                 return null;
             }
         }, timeoutMillis);
     } catch (TimeoutException e) {
         throw new NonStopCacheException("Unable to add cache [" + cache.getCacheConfiguration().getName() + "] within "
                 + timeoutMillis + " msecs", e);
     } catch (InterruptedException e) {
         throw new CacheException(e);
     }
 } else {
     cache.initialise();
 }

 if (!allowsDynamicCacheConfig) {
     cache.disableDynamicFeatures();
 }

 try {
     cache.bootstrap();
 } catch (CacheException e) {
     LOG.warn("Cache " + cache.getName() + "requested bootstrap but a CacheException occured. " + e.getMessage(), e);
 }
 ehcache = ehcaches.putIfAbsent(cache.getName(), cache);
 if (ehcache != null) {
     if (strict) {
         throw new ObjectExistsException("Cache " + cache.getName() + " already exists");
     } else {
         return ehcache;
     }
 }

 // Don't notify initial config. The init method of each listener should take care of this.
 if (status.equals(Status.STATUS_ALIVE)) {
     cacheManagerEventListenerRegistry.notifyCacheAdded(cache.getName());
 }

 return cache;
```
}

/**
- Checks whether a cache of type ehcache exists.
- @param cacheName
- ```
       the cache name to check for
```
- @return true if it exists
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_ALIVE}
```
*/
public boolean cacheExists(String cacheName) throws IllegalStateException {
checkStatus();
return (ehcaches.get(cacheName) != null);
}

/**
- Removes all caches using {@link #removeCache} for each cache.
  */
  public void removalAll() {
  String[] cacheNames = getCacheNames();
  for (String cacheName : cacheNames) {
  removeCache(cacheName);
  }
  }
/**
- Remove a cache from the CacheManager. The cache is disposed of.
- @param cacheName
- ```
       the cache name
```
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_ALIVE}
```
*/
public void removeCache(String cacheName) throws IllegalStateException {
checkStatus();
```
 // NPE guard
 if (cacheName == null || cacheName.length() == 0) {
     return;
 }
 Ehcache cache = ehcaches.remove(cacheName);
 if (cache != null && cache.getStatus().equals(Status.STATUS_ALIVE)) {
     cache.dispose();
     configuration.getCacheConfigurations().remove(cacheName);
     cacheManagerEventListenerRegistry.notifyCacheRemoved(cache.getName());
 }
```
}

/**
- Shuts down the CacheManager.
- If the shutdown occurs on the singleton, then the singleton is removed, so that if a singleton access method is called, a new
- singleton will be created.
- By default there is no shutdown hook (ehcache-1.3-beta2 and higher).
- Set the system property net.sf.ehcache.enableShutdownHook=true to turn it on.
  */
  public void shutdown() {
  synchronized (CacheManager.class) {
  if (status.equals(Status.STATUS_SHUTDOWN)) {
  LOG.debug("CacheManager already shutdown");
  return;
  }
  for (CacheManagerPeerProvider cacheManagerPeerProvider : cacheManagerPeerProviders.values()) {
  if (cacheManagerPeerProvider != null) {
  cacheManagerPeerProvider.dispose();
  }
  }
```
 // cancel the cacheManager timer and all tasks
 if (cacheManagerTimer != null) {
     cacheManagerTimer.cancel();
     cacheManagerTimer.purge();
 }

 cacheManagerEventListenerRegistry.dispose();

 synchronized (CacheManager.class) {
     ALL_CACHE_MANAGERS.remove(this);

     for (Ehcache cache : ehcaches.values()) {
         if (cache != null) {
             cache.dispose();
         }
     }
     if (defaultCache != null) {
         defaultCache.dispose();
     }
     status = Status.STATUS_SHUTDOWN;
     XARequestProcessor.shutdown();

     // only delete singleton if the singleton is shutting down.
     if (this == singleton) {
         singleton = null;
     }
     terracottaClient.shutdown();
     transactionController = null;
     removeShutdownHook();
     nonstopExecutorServiceFactory.shutdown(this);
 }
```
  }
  }
/**
- Returns a list of the current cache names.
- @return an array of {@link String}s
- @throws IllegalStateException
- ```
        if the cache is not {@link Status#STATUS_ALIVE}
```
*/
public String[] getCacheNames() throws IllegalStateException {
checkStatus();
String[] list = new String[ehcaches.size()];
return ehcaches.keySet().toArray(list);
}

/**
- Checks the state of the CacheManager for legal operation
  */
  protected void checkStatus() {
  if (!(status.equals(Status.STATUS_ALIVE))) {
  if (status.equals(Status.STATUS_UNINITIALISED)) {
  throw new IllegalStateException("The CacheManager has not yet been initialised. It cannot be used yet.");
  } else if (status.equals(Status.STATUS_SHUTDOWN)) {
  throw new IllegalStateException("The CacheManager has been shut down. It can no longer be used.");
  }
  }
  }
/**
- Gets the status attribute of the Ehcache
- @return The status value from the Status enum class
  */
  public Status getStatus() {
  return status;
  }
/**
- Clears the contents of all caches in the CacheManager, but without
- removing any caches.
- This method is not synchronized. It only guarantees to clear those elements in a cache at the time that the
- {@link Ehcache#removeAll()} mehod on each cache is called.
  */
  public void clearAll() throws CacheException {
  String[] cacheNames = getCacheNames();
  
  LOG.debug("Clearing all caches");
  for (String cacheName : cacheNames) {
  Ehcache cache = getEhcache(cacheName);
  cache.removeAll();
  }
  }
/**
- Clears the contents of all caches in the CacheManager with a name starting with the prefix,
- but without removing them.
- This method is not synchronized. It only guarantees to clear those elements in a cache at the time that the
- {@link Ehcache#removeAll()} method on each cache is called.
- @param prefix
- ```
       The prefix the cache name should start with
```
- @throws CacheException
- @since 1.7.2
  */
  public void clearAllStartingWith(String prefix) throws CacheException {
  // NPE guard
  if (prefix == null || prefix.length() == 0) {
  return;
  }
  
  for (Object o : ehcaches.entrySet()) {
  Map.Entry entry = (Map.Entry) o;
  String cacheName = (String) entry.getKey();
  if (cacheName.startsWith(prefix)) {
  if (LOG.isDebugEnabled()) {
  LOG.debug("Clearing cache named '" + cacheName + "' (matches '" + prefix + "' prefix");
  }
  ((Ehcache) entry.getValue()).removeAll();
  }
  }
  }
/**
- Gets the CacheManagerPeerProvider, matching the given scheme
- For distributed caches, the peer provider finds other cache managers and their caches in the same cluster
- @param scheme
- ```
       the replication scheme to use. Schemes shipped with ehcache are RMI, JGROUPS, JMS
```
- @return the provider, or null if one does not exist
  */
  public CacheManagerPeerProvider getCacheManagerPeerProvider(String scheme) {
  return cacheManagerPeerProviders.get(scheme);
  }
/**
- @return Read-only map of the registered {@link CacheManagerPeerProvider}s keyed by scheme.
  */
  public Map<String, CacheManagerPeerProvider> getCacheManagerPeerProviders() {
  return Collections.unmodifiableMap(this.cacheManagerPeerProviders);
  }
/**
- When CacheManage is configured as part of a cluster, a CacheManagerPeerListener will
- be registered in it. Use this to access the individual cache listeners
- @param scheme
- ```
       the replication scheme to use. Schemes shipped with ehcache are RMI, JGROUPS, JMS
```
- @return the listener, or null if one does not exist
  */
  public CacheManagerPeerListener getCachePeerListener(String scheme) {
  return cacheManagerPeerListeners.get(scheme);
  }
/**
- Returns the composite listener. A notification sent to this listener will notify all registered
- listeners.
- @return null if none
- @see "getCacheManagerEventListenerRegistry"
  */
  public CacheManagerEventListener getCacheManagerEventListener() {
  return cacheManagerEventListenerRegistry;
  }
/**
- Same as getCacheManagerEventListenerRegistry().registerListener(cacheManagerEventListener);
- Left for backward compatiblity
- @param cacheManagerEventListener
- ```
       the listener to set.
```
- @see "getCacheManagerEventListenerRegistry"
  */
  public void setCacheManagerEventListener(CacheManagerEventListener cacheManagerEventListener) {
  getCacheManagerEventListenerRegistry().registerListener(cacheManagerEventListener);
  }
/**
- Gets the CacheManagerEventListenerRegistry. Add and remove listeners here.
  */
  public CacheManagerEventListenerRegistry getCacheManagerEventListenerRegistry() {
  return cacheManagerEventListenerRegistry;
  }
/**
- Replaces in the map of Caches managed by this CacheManager an Ehcache with a decorated version of the same
- Ehcache. CacheManager can operate fully with a decorated Ehcache.
- Ehcache Decorators can be used to obtain different behaviour from an Ehcache in a very flexible way. Some examples in ehcache are:
- 2. {@link net.sf.ehcache.constructs.blocking.BlockingCache} - A cache that blocks other threads from getting a null element until
  3. the first thread has placed a value in it.
  5. {@link net.sf.ehcache.constructs.blocking.SelfPopulatingCache} - A BlockingCache that has the additional property of knowing how
  6. to load its own entries.
- Many other kinds are possible.
- It is generally required that a decorated cache, once constructed, is made available to other execution threads. The simplest way of
- doing this is to substitute the original cache for the decorated one here.
- Note that any overwritten Ehcache methods will take on new behaviours without casting. Casting is only required for new methods that
- the decorator introduces. For more information see the well known Gang of Four Decorator pattern.
- @param ehcache
- @param decoratedCache
- ```
       An implementation of Ehcache that wraps the original cache.
```
- @throws CacheException
- ```
        if the two caches do not equal each other.
```
*/
public void replaceCacheWithDecoratedCache(Ehcache ehcache, Ehcache decoratedCache) throws CacheException {
if (!ehcache.equals(decoratedCache)) {
throw new CacheException("Cannot replace " + decoratedCache.getName() + " It does not equal the incumbent cache.");
}
```
 String cacheName = ehcache.getName();
 if (!ehcaches.replace(cacheName, ehcache, decoratedCache)) {
     if (cacheExists(cacheName)) {
         throw new CacheException("Cache '" + ehcache.getName() + "' managed with this CacheManager doesn't match!");
     } else {
         throw new CacheException("Cache '" + cacheName + "' isn't associated with this manager (anymore?)");
     }
 }
```
}

/**
- Gets the name of the CacheManager. This is useful for distinguishing multiple CacheManagers
- @return the name, or the output of toString() if it is not set.
- @see #toString() which uses either the name or Object.toString()
  */
  public String getName() {
  if (name != null) {
  return name;
  } else {
  return super.toString();
  }
  }
/**
- Indicate whether the CacheManager is named or not.
- @return True if named
  */
  public boolean isNamed() {
  return name != null;
  }
/**
- Sets the name of the CacheManager. This is useful for distinguishing multiple CacheManagers
- in a monitoring situation.
- @param name
- ```
       a name with characters legal in a JMX ObjectName
```
*/
public void setName(String name) {
this.name = name;
try {
mbeanRegistrationProvider.reinitialize(terracottaClient.getClusteredInstanceFactory());
} catch (MBeanRegistrationProviderException e) {
throw new CacheException("Problem in reinitializing MBeanRegistrationProvider - "
+ mbeanRegistrationProvider.getClass().getName(), e);
}
}

/**
- @return either the name of this CacheManager, or if unset, Object.toString()
  */
  @Override
  public String toString() {
  return getName();
  }
/**
- Returns the disk store path. This may be null if no caches need a DiskStore and none was configured.
- The path cannot be changed after creation of the CacheManager. All caches take the disk store path
- from this value.
- @return the disk store path.
  */
  public String getDiskStorePath() {
  return diskStorePath;
  }
/**
- Returns a {@link FailSafeTimer} associated with this
- @return The {@link FailSafeTimer} associated with this cache manager
- @since 1.7
  */
  public FailSafeTimer getTimer() {
  return cacheManagerTimer;
  }
/**
- Returns access to information about the cache cluster.
- @param scheme The clustering scheme to retrieve information about (such as "Terracotta")
- @return Cluster API (never null, but possibly a simple single node implementation)
- @throws ClusterSchemeNotAvailableException If the CacheCluster specified by scheme is not available.
- @see ClusterScheme
- @since 2.0
  */
  public CacheCluster getCluster(ClusterScheme scheme) throws ClusterSchemeNotAvailableException {
  switch (scheme) {
  case TERRACOTTA:
  if (null == terracottaClient.getClusteredInstanceFactory()) {
  throw new ClusterSchemeNotAvailableException(ClusterScheme.TERRACOTTA, "Terracotta cluster scheme is not available");
  }
  return terracottaClient.getCacheCluster();
  default:
  return NoopCacheCluster.INSTANCE;
  }
  }
/**
- Returns the original configuration text for this
- @return Returns the original configuration text for this {@link CacheManager}
  */
  public String getOriginalConfigurationText() {
  if (configuration.getConfigurationSource() == null) {
  return "Originally configured programmatically. No original configuration source text.";
  } else {
  Configuration originalConfiguration = configuration.getConfigurationSource().createConfiguration();
  return ConfigurationUtil.generateCacheManagerConfigurationText(originalConfiguration);
  }
  }
/**
- Returns the active configuration text for this
- @return Returns the active configuration text for this {@link CacheManager}
  */
  public String getActiveConfigurationText() {
  return ConfigurationUtil.generateCacheManagerConfigurationText(configuration);
  }
/**
- Returns the original configuration text for the input cacheName
- @param cacheName
- @return Returns the original configuration text for the input cacheName
- @throws CacheException if the cache with cacheName does not exist in the original config
  */
  public String getOriginalConfigurationText(String cacheName) throws CacheException {
  if (configuration.getConfigurationSource() == null) {
  return "Originally configured programmatically. No original configuration source text.";
  } else {
  Configuration originalConfiguration = configuration.getConfigurationSource().createConfiguration();
  CacheConfiguration cacheConfiguration = originalConfiguration.getCacheConfigurations().get(cacheName);
  if (cacheConfiguration == null) {
  throw new CacheException("Cache with name '" + cacheName + "' does not exist in the original configuration");
  }
  return ConfigurationUtil.generateCacheConfigurationText(cacheConfiguration);
  }
  }
/**
- Returns the active configuration text for the input cacheName
- @param cacheName
- @return Returns the active configuration text for the input cacheName
- @throws CacheException if the cache with cacheName does not exist
  */
  public String getActiveConfigurationText(String cacheName) throws CacheException {
  CacheConfiguration config = configuration.getCacheConfigurations().get(cacheName);
  if (config == null) {
  throw new CacheException("Cache with name '" + cacheName + "' does not exist");
  }
  return ConfigurationUtil.generateCacheConfigurationText(config);
  }
/**
- Get the CacheManager configuration
- @return the configuration
  */
  Configuration getConfiguration() {
  return configuration;
  }
/**
- {@inheritDoc}
  */
  @Override
  public int hashCode() {
  if (name != null) {
  return name.hashCode();
  } else {
  return super.hashCode();
  }
  }
/**
- Only adds the cache to the CacheManager should not one with the same name already be present
- @param cache The Ehcache to be added
- @return the instance registered with the CacheManager, the cache instance passed in if it was added; or null if Ehcache is null
  */
  public Ehcache addCacheIfAbsent(final Ehcache cache) {
  checkStatus();
  return cache == null ? null : addCacheNoCheck(cache, false);
  }
/**
- Only creates and adds the cache to the CacheManager should not one with the same name already be present
- @param cacheName the name of the Cache to be created
- @return the Ehcache instance created and registered; null if cacheName was null or of length 0
  */
  public Ehcache addCacheIfAbsent(final String cacheName) {
  checkStatus();
  
  // NPE guard
  if (cacheName == null || cacheName.length() == 0) {
  return null;
  }
  
  Ehcache ehcache = ehcaches.get(cacheName);
  if (ehcache == null) {
  Ehcache clonedDefaultCache = cloneDefaultCache(cacheName);
  if (clonedDefaultCache == null) {
  throw new CacheException(NO_DEFAULT_CACHE_ERROR_MSG);
  }
  addCacheIfAbsent(clonedDefaultCache);
  for (Ehcache createdCache : createDefaultCacheDecorators(clonedDefaultCache)) {
  addOrReplaceDecoratedCache(clonedDefaultCache, createdCache);
  }
  }
  return ehcaches.get(cacheName);
  }
private Ehcache cloneDefaultCache(final String cacheName) {
if (defaultCache == null) {
return null;
}
Ehcache cache;
try {
cache = (Ehcache) defaultCache.clone();
} catch (CloneNotSupportedException e) {
throw new CacheException("Failure cloning default cache. Initial cause was " + e.getMessage(), e);
}
if (cache != null) {
cache.setName(cacheName);
}
return cache;
}

private List createDefaultCacheDecorators(Ehcache underlyingCache) {
return ConfigurationHelper.createDefaultCacheDecorators(underlyingCache, configuration.getDefaultCacheConfiguration());
}

/**
- Get the TransactionController
- @return the TransactionController
  */
  public TransactionController getTransactionController() {
  return transactionController;
  }
/**
- Create a TransactionIDFactory
- @return a TransactionIDFactory
  */
  TransactionIDFactory createTransactionIDFactory() {
  TransactionIDFactory transactionIDFactory;
  if (terracottaClient.getClusteredInstanceFactory() != null) {
  transactionIDFactory = terracottaClient.getClusteredInstanceFactory().createTransactionIDFactory(getClusterUUID());
  } else {
  transactionIDFactory = new TransactionIDFactoryImpl();
  }
  return transactionIDFactory;
  }
/**
- Create a soft lock factory for a specific cache
- @param cache the cache to create the soft lock factory for
- @return a SoftLockFactory
  */
  SoftLockFactory createSoftLockFactory(Ehcache cache) {
  SoftLockFactory softLockFactory;
  if (cache.getCacheConfiguration().isTerracottaClustered()) {
  softLockFactory = getClusteredInstanceFactory(cache).getOrCreateSoftLockFactory(cache.getName());
  } else {
  softLockFactory = softLockFactories.get(cache.getName());
  if (softLockFactory == null) {
  softLockFactory = new ReadCommittedSoftLockFactoryImpl(cache.getName());
  SoftLockFactory old = softLockFactories.putIfAbsent(cache.getName(), softLockFactory);
  if (old != null) {
  softLockFactory = old;
  }
  }
  }
  return softLockFactory;
  }
private void clusterRejoinStarted() {
for (Ehcache cache : ehcaches.values()) {
if (cache instanceof Cache) {
if (cache.getCacheConfiguration().isTerracottaClustered()) {
((Cache) cache).clusterRejoinStarted();
}
}
}
// shutdown the current nonstop executor service
nonstopExecutorServiceFactory.shutdown(this);
}

/**
- This method is called when the Terracotta Cluster is rejoined. Reinitializes all terracotta clustered caches in this cache manager
  */
  private void clusterRejoinComplete() {
  // restart nonstop executor service
  nonstopExecutorServiceFactory.getOrCreateNonstopExecutorService(this);
  for (Ehcache cache : ehcaches.values()) {
  if (cache instanceof Cache) {
  if (cache.getCacheConfiguration().isTerracottaClustered()) {
  ((Cache) cache).clusterRejoinComplete();
  }
  }
  }
  if (mbeanRegistrationProvider.isInitialized()) {
  // re-register mbeans
  try {
  mbeanRegistrationProvider.reinitialize(terracottaClient.getClusteredInstanceFactory());
  } catch (MBeanRegistrationProviderException e) {
  throw new CacheException("Problem in reinitializing MBeanRegistrationProvider - "
  + mbeanRegistrationProvider.getClass().getName(), e);
  }
  }
  // recreate TransactionController with fresh TransactionIDFactory
  transactionController = new TransactionController(createTransactionIDFactory(), configuration
  .getDefaultTransactionTimeoutInSeconds());
  }
/**
- Return the {@link NonstopExecutorService} associated with this cacheManager
- @return the {@link NonstopExecutorService} associated with this cacheManager
  */
  protected NonstopExecutorService getNonstopExecutorService() {
  return nonstopExecutorServiceFactory.getOrCreateNonstopExecutorService(this);
  }
  }

posted @ 2021-07-07 18:05 任国强阅读(62) 评论(0) 编辑收藏举报

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rgqancy

波峰波谷，康波人生。棋在盘中走，人在波中行。波粒二象性（观察者理论）。

Java from design pattern singleton to implement that is terracotta ehcache cacheManager

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rgqancy

波峰波谷，康波人生。 棋在盘中走，人在波中行。 波粒二象性（观察者理论）。

Java from design pattern singleton to implement that is terracotta ehcache cacheManager

公告

波峰波谷，康波人生。棋在盘中走，人在波中行。波粒二象性（观察者理论）。