org.aredis.cache

Class RedisClassDescriptorStorage

java.lang.Object

org.aredis.io.ClassDescriptorStorage

org.aredis.cache.RedisClassDescriptorStorage

public class RedisClassDescriptorStorage
extends ClassDescriptorStorage

Implementation of ClassDescriptorStorage used by aredis that stores the ClassDescriptors on a redis server. The data is serialized using java serialization and saved under the specified key. The default key is JAVA_CL_DESCRIPTORS. The key is non-volatile.

Note that aredis uses this class via PerConnectionRedisClassDescriptorStorageFactory which is the default or RedisClassDescriptorStorageFactory.

The updateClassDescriptors method uses WATCH-MULTI-EXEC commands along with checking of versionNo to avoid dirty update.

Author:

Suresh

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_DESCRIPTORS_KEY Constant for the default key in which to store the Class Descriptors.

Constructor Summary

Constructors

Constructor and Description
RedisClassDescriptorStorage(AsyncRedisConnection paredis) Creates a storage for the given Redis Connection with the defalt key "JAVA_CL_DESCRIPTORS".
RedisClassDescriptorStorage(AsyncRedisConnection paredis, String pdescriptorsKey, int pdbIndex) Creates a storage for the given Redis Connection and descriptors key.

Method Summary

Methods

Modifier and Type	Method and Description
ClassDescriptors	getMasterClassDescriptors(boolean refreshFromStore) Gets the class descriptors from the store.
boolean	updateClassDescriptors(ClassDescriptors updatedDescriptors) Updates the class descriptors based on optimistic locking (Dirty write check) similar to WATCH-MULTI-EXEC or in redis or CAS in memcached.

Methods inherited from class org.aredis.io.ClassDescriptorStorage

getCleanupAgeDays, getUseTimeUpdateInterval, setCleanupAgeDays, setUseTimeUpdateInterval, updateTimingsAndCleanup

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_DESCRIPTORS_KEY

public static final String DEFAULT_DESCRIPTORS_KEY

Constant for the default key in which to store the Class Descriptors.

See Also:

Constant Field Values

Constructor Detail

RedisClassDescriptorStorage

public RedisClassDescriptorStorage(AsyncRedisConnection paredis,
                           String pdescriptorsKey,
                           int pdbIndex)

Creates a storage for the given Redis Connection and descriptors key. The type of the connection must be STANDALONE or SHARED.

Parameters:

paredis - Async Redis Connection to Use

pdescriptorsKey - Key in which to store the Descriptors

pdbIndex - The dbIndex to use. This could be different from that in aredis

RedisClassDescriptorStorage

public RedisClassDescriptorStorage(AsyncRedisConnection paredis)

Creates a storage for the given Redis Connection with the defalt key "JAVA_CL_DESCRIPTORS". The type of the connection must be STANDALONE or SHARED. The dbIndex of the passed redis connection is the dbIndex used.

Parameters:

paredis - Async Redis Connection to Use

Method Detail

getMasterClassDescriptors

public ClassDescriptors getMasterClassDescriptors(boolean refreshFromStore)
                                           throws IOException

Description copied from class: ClassDescriptorStorage

Gets the class descriptors from the store. If refreshFromStore is false then a local copy if available is returned. If refreshFromStore is true or a local copy is not available then it is fetched from the store. If the class descriptors are not yet stored then a new instance is created and returned.

Specified by:

getMasterClassDescriptors in class ClassDescriptorStorage

Parameters:

refreshFromStore - Whether to fetch the Class Descriptors from store even if a local copy is available

Returns:

Non null ClassDescriptors

Throws:

IOException - In case of error fetching the ClassDescriptors

updateClassDescriptors

public boolean updateClassDescriptors(ClassDescriptors updatedDescriptors)
                               throws IOException

Description copied from class: ClassDescriptorStorage

Updates the class descriptors based on optimistic locking (Dirty write check) similar to WATCH-MULTI-EXEC or in redis or CAS in memcached. The passed Class Descriptors should be saved if the versionNo of the passed descriptors is 1 greater than that in the store. If the descriptors have not yet been created then the incoming versionNo should be 1. If the update fails then the local ClassDescriptors copy should be replaced with the latest copy from the store. The caller will then retry the operation by using the new ClassDescriptors.

Specified by:

updateClassDescriptors in class ClassDescriptorStorage

Parameters:

updatedDescriptors - Updated Class Descriptors

Returns:

true if the operation succeeds, false if it fails because it has already been updated since the local copy was fetched.

Throws:

IOException - In case there is an error updating the ClassDescriptors