Package oracle.kv.coherence

Class NoSQLBinaryStore

java.lang.Object
com.tangosol.util.Base
oracle.kv.coherence.NoSQLBinaryStore
All Implemented Interfaces:
BinaryEntryStore, XmlConfigurable
public class NoSQLBinaryStore extends Base implements BinaryEntryStore
Oracle NoSQL Database implementation of the BinaryEntryStore interface. This implementation uses a single Oracle NoSQL Database handler to deal with single operation and bulk operations that have been requested by the Oracle Coherence layer.

Users are not generally expected to directly interact with instances of this class. It is expected that the class is managed by Oracle Coherence as the result of XML configuration supplied to Coherence at program startup. The documentation contained in this class is intended primarily to explain the XML configuration options. However, this class does define two static functions, which provide access to the key encode/decode logic, if needed.

Usage

In order to use the NoSQLBinaryStore module, you must configure an Oracle Coherence cache to use it. NoSQLBinaryStore is a BinaryEntryStore, which implies that the cache must be defined as part of a distributed-scheme.

This implementation handles requests to load data into the cache when a key is not present, to store data when changes are made to the cache, and to delete a KV entry when a remove is performed on the cache. These operations require converting the Oracle Coherence application's representation of a cache key and a cache value into a form that meets the needs of Oracle NoSQL Database.

A BinaryEntryStore relies on the Coherence application for serialization and deserialization of data. * In the default mode of operation, where no key-mapper has been specified, the cache key objects can be any object type, but the keys are handled differently, depending on the the type. For key objects of type Key, the objects are used directly as the Oracle NoSQL Database Key for the operation. For all other object types, the serialized form of the object is encoded using the encodeBinaryKey(byte[]) method, and the result is treated as a single path component relative to the components in the key-prefix option, if specified, or as the single top-level major path component if key-prefix was not specified.

If an application needs greater control over the way in which Oracle Coherence keys are mapped to Oracle NoSQL Database Key objects, the cache can be configured with a key-mapper, which can provide arbitrary translation of key types. This key-mapper must implement the CacheKeyMapper interface.

The Oracle Coherence value objects can be of any type, provided they can be serialized by Oracle Coherence. The binary data as serialized by Oracle Coherence is used to construct a Value.

The NoSQLBinaryStore also needs to access a Oracle NoSQL Database instance. In addition to the basic information needed to connect to the database, a number of additional store interaction properties are also configurable, allowing the developer to set Durability, Consistency in the cache configuration.

XML Configuration Options

The various configuration parameters to adjust the behavior to your application's specific requirements are set within the cache definition XML using <kv:XXX> style elements, where XXX are:

store-name - (Required) The Oracle NoSQL Database instance name that is used to provide persistence for your Oracle Coherence cache.

helper-hosts - (Required) A comma-separated list of helperHost:port values that serve as the gateway to the Oracle NoSQL Database instance.

key-prefix - (Optional) A prefix to apply to relative keys. Not valid in conjunction with the keyMapper option. The value specified must begin with a '/' character and indicates zero or more major key path components to prepend to any key passed to the cache store that is not of type Key. See Key.toString() for a of the format of the key strings.

key-mapper - (Optional) Names a class with a no-arg constructor and which implements the CacheKeyMapper interface. Provides application rules for mapping Coherence cache keys to Oracle NoSQL Database keys. This is not valid in conjunction with keyPrefix.

Consistency parameters

consistency - (Optional) Specifies the type of consistency to use during lookups. Valid values are:

  • ABSOLUTE
  • NONE_REQUIRED
  • NONE_REQUIRED_NO_MASTER
  • TIME - requires consistencyTimeLag and consistencyTimeout

consistency-time-lag - (Optional) Specifies the maximum time lag for valid consistency. Time durations can be specified using standard Oracle Coherence time unit suffixes (e.g. 1ns, 1us, 1ms, 1s)

consistency-timeout - (Optional) Specifies the timeout for waiting for consistency. Time durations can be specified using standard Oracle Coherence time unit suffixes (e.g. 1ns, 1us, 1ms, 1s)

Durability parameters

durability-master-sync - (Optional) Specifies the Durability completeness for writes at the master replication node. Valid values are:

  • SYNC
  • NO_SYNC
  • WRITE_NO_SYNC

durability-replica-sync - (Optional) Specifies the Durability completeness for writes at replica nodes. Valid values are as shown for the durabilityMasterSync parameter.

durability-replica-ack - (Optional) Specifies the Durability completeness for replica nodes. Valid values are:

  • ALL
  • NONE
  • SIMPLE_MAJORITY

Example

Here is an example for the configuration of an Oracle Coherence cache using the NoSQLBinaryStore module. 
 
  <distributed-scheme>
    <scheme-name>MyBinaryScheme</scheme-name>
    <service-name>MyBinaryService</service-name>
    <backing-map-scheme>
      <read-write-backing-map-scheme>
        <internal-cache-scheme>
          <local-scheme />
        </internal-cache-scheme>
        <cachestore-scheme>
          <kv:binary-cache-store>
            <kv:store-name>kvstore</kv:store-name>
            <kv:helper-hosts>myhost:5000</kv:helper-hosts>
          </kv:binary-cache-store>
        </cachestore-scheme>
      </read-write-backing-map-scheme>
    </backing-map-scheme>
    <autostart>true</autostart>
  </distributed-scheme>

Coherence 3.7.1 Support

You may use this module with Coherence version 3.7.1, however it's highly recommended for you to upgrade to the latest version of Coherence. You may visit the package summary of the oracle.kv.coherence package for how to configure a NoSQL backed cache with Coherence 3.7.1.

  • Method Details

    • encodeBinaryKey

      public static String encodeBinaryKey(byte[] bKey)
      Encode a binary key in ascii form so that it is suitable for use as a NoSQL key.
      Parameters:
      bKey - the binary key value to be encoded
      Returns:
      the binary key in string from

    • decodeBinaryKey

      public static byte[] decodeBinaryKey(String strKey)
      Decode a binary key from ascii form.
      Parameters:
      strKey - the encoded binary key value to be decoded
      Returns:
      the binary key value

    • setConfig

      public void setConfig(XmlElement config)
      Set the cache configuration based on XML configuration specified by the user.
      Specified by:
      setConfig in interface XmlConfigurable
      Throws:
      IllegalStateException - if this is not the first call to setConfig

    • getConfig

      public XmlElement getConfig()
      Returns the configuration of this Store
      Specified by:
      getConfig in interface XmlConfigurable
      Returns:
      The XML configuration specified for this module. This may be null if no call to setConfig has previously been made.

    • instantiateKeyMapper

      protected void instantiateKeyMapper(String mapperClassName)
      Given a class name, create an instance of the class and assign it to the cacheKeyMapper variable.
      Parameters:
      mapperClassName - The name of a class, which must implement the CacheKeyMapper interface, and have a no-args constructor.

    • resolveStringKey

      protected Key resolveStringKey(String keyString)
      Given a String key, turn it into a NoSQL Key object, but applying prefix if needed.

    • connectNoSQL

      protected void connectNoSQL()
      Obtain the NoSQL database handler being used to connect.