Package org.springframework.data.gemfire.cache

Class CallableCacheLoaderAdapter<K,V>

java.lang.Object

org.springframework.data.gemfire.cache.CallableCacheLoaderAdapter<K,V>

All Implemented Interfaces:

Callable<V>, CacheCallback, CacheLoader<K,V>, Declarable

public class CallableCacheLoaderAdapter<K,V>
extends Object
implements Callable<V>, CacheLoader<K,V>

The CallableCacheLoaderAdapter class is a Callable and GemFire CacheLoader implementation that adapts the Callable interface into an instance of the CacheLoader interface. This class is useful in situations where GemFire developers have several CacheLoader implementations that they wish to use with Spring's Cache Abstraction.

Since:

1.9.0

Author:

John Blum

See Also:

• Callable
• CacheLoader
• LoaderHelper
• Region

Constructor Summary

Constructors

Constructor	Description
CallableCacheLoaderAdapter(CacheLoader<K,V> delegate)	Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader.
CallableCacheLoaderAdapter(CacheLoader<K,V> delegate, K key, Region<K,V> region)	Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader and is initialized with the given key for which the value will be loaded along with the Region in which the entry (key/value) belongs.
CallableCacheLoaderAdapter(CacheLoader<K,V> delegate, K key, Region<K,V> region, Object argument)	Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader and is initialized with the given key for which the value will be loaded along with the Region in which the entry (key/value) belongs.

Method Summary

Modifier and Type	Method	Description
final V	call()	Invoked to load a cache value for the specified key.
void	close()	Closes any resources used by this CacheLoader.
protected Object	getArgument()	Gets the argument used by this CacheLoader to load the value for the specified key.
protected CacheLoader<K,V>	getCacheLoader()	The CacheLoader delegate used to actually load the cache value for the specified key.
protected K	getKey()	The specified key for which a value will be loaded by this CacheLoader.
protected Region<K,V>	getRegion()	Returns the Region to which the entry (key/value) belongs.
V	load(LoaderHelper<K,V> loaderHelper)	Loads a value for the specified cache (i.e.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.geode.cache.Declarable

init, initialize

Constructor Details

CallableCacheLoaderAdapter

public CallableCacheLoaderAdapter(CacheLoader<K,V> delegate)

Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader.

Parameters:

delegate - the CacheLoader delegated to by this adapter.

See Also:

• CallableCacheLoaderAdapter(CacheLoader, Object, Region, Object)
• CacheLoader

CallableCacheLoaderAdapter

public CallableCacheLoaderAdapter(CacheLoader<K,V> delegate,
 K key,
 Region<K,V> region)

Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader and is initialized with the given key for which the value will be loaded along with the Region in which the entry (key/value) belongs.

Parameters:

delegate - the CacheLoader delegated to by this adapter.

key - the key for which the value will be loaded.

region - the Region in which the entry (key/value) belongs.

See Also:

• CallableCacheLoaderAdapter(CacheLoader, Object, Region, Object)
• CacheLoader
• Region

CallableCacheLoaderAdapter

public CallableCacheLoaderAdapter(CacheLoader<K,V> delegate,
 K key,
 Region<K,V> region,
 Object argument)

Constructs an instance of the CallableCacheLoaderAdapter that delegates to the given CacheLoader and is initialized with the given key for which the value will be loaded along with the Region in which the entry (key/value) belongs. Additionally, an argument may be specified for use with the CacheLoader delegate.

Parameters:

delegate - the CacheLoader delegated to by this adapter.

key - the key for which the value will be loaded.

region - the Region in which the entry (key/value) belongs.

argument - the Object argument used with the CacheLoader delegate.

See Also:

• CallableCacheLoaderAdapter(CacheLoader, Object, Region, Object)
• CacheLoader
• Region

Method Details

getArgument

protected Object getArgument()

Gets the argument used by this CacheLoader to load the value for the specified key.

Returns:

an Object argument used by this CacheLoader when loading the value for the specified key.

getCacheLoader

protected CacheLoader<K,V> getCacheLoader()

The CacheLoader delegate used to actually load the cache value for the specified key.

Returns:

a reference to the actual CacheLoader used when loading the cache value for the specified key.

See Also:

• CacheLoader

getKey

protected K getKey()

The specified key for which a value will be loaded by this CacheLoader.

Returns:

the specified key for which the value will be loaded.

getRegion

protected Region<K,V> getRegion()

Returns the Region to which the entry (key/value) belongs.

Returns:

the Region to which the entry belongs.

See Also:

• Region

call

public final V call()
             throws Exception

Invoked to load a cache value for the specified key. Delegates to load(LoaderHelper).

Specified by:

call in interface Callable<K>

Returns:

the loaded cache value for the specified key.

Throws:

IllegalStateException - if the Region or key references are null.

Exception - if the load operation fails.

See Also:

• load(LoaderHelper)

close

public void close()

Closes any resources used by this CacheLoader. Delegates to the underlying CacheLoader.

Specified by:

close in interface CacheCallback

See Also:

• getCacheLoader()

load

public V load(LoaderHelper<K,V> loaderHelper)
       throws CacheLoaderException

Loads a value for the specified cache (i.e. Region) and key with the help of the LoaderHelper. Delegates to the underlying CacheLoader.

Specified by:

load in interface CacheLoader<K,V>

Parameters:

loaderHelper - a LoaderHelper object passed in from cache service providing access to the key, Region, argument, and netSearch.

Returns:

the value supplied for the specified key, or null if no value can be supplied. A local loader will always be invoked if one exists. Otherwise one remote loader is invoked. Returning null causes Region.get(Object, Object) to return null.

Throws:

CacheLoaderException - if an error occurs during the load operation. This exception, or any other Exception thrown by this method will be propagated back to the application from the Region.get(Object) method.

See Also:

• CacheLoader.load(LoaderHelper)
• LoaderHelper
• getCacheLoader()