CacheNode

java.lang.Object
- org.qbroker.node.Node
- - org.qbroker.node.CacheNode

All Implemented Interfaces:

MessageNode
```
public class CacheNode
extends Node
```
CacheNode picks up JMS messages as the requests and looks for cached responses according to their content and predefined rulesets. If a valid cache is available, its content will be loaded to the incoming message before it is routed to the outlink of done. If there is no cache or the cache has expired, the incoming message will be routed to the right outlink as a request. Once the response is collected, CacheNode evaluates the return code and caches the response if it is a success. The message will be routed to the outlink of done. In case of failure, the incoming messages will be routed to the outlink failure. If none of the rulesets matches the incoming messages, they will be put to the outlink of nohit. The rest of the outlinks are collectibles to fulfill requests.

CacheNode contains a number of predefined rulesets. These rulesets categorize messages into non-overlapping groups via the property filter. Therefore, each ruleset defines a unique message group. If the associated outlink is none of the fixed outlinks and KeyTemplate is also defined in a ruleset, it is a ruleset of dynamic cache. That outlink is a collectible used to fulfill requests for caching. In a dynamic cache ruleset, other cache parameters may be defined as well, such as TimeToLive, RequestType, DataField, Template and Substitution, etc. TimeToLive controls how long to cache the result. DataField, Template and Substitution are used to modify the request for cache. By default, the request is assumed already built-in. If the associated outlink is one the fixed outlinks and KeyTemplate is defined also, the ruleset is of static cache. In this case, StaticCache can be predefined in the ruleset. It is just a map with predefined key-value pairs. Each cache ruleset maintains its own dedicated cache. Hence, different message groups may have their own ways for the keys and policies. Further more, CacheNode always creates an extra ruleset, nohit. Ruleset of nohit is for all the messages not hitting any of the predefined rulesets. For a cache ruleset, the number of collected responses is stored in RULE_PEND. So it is easy to track the hit ratio of the cache.

CacheNode also supports the invalidation rulesets. The invalidation ruleset is simliar to the cache ruleset. The only difference is that the former has also defined TargetRule. TargetRule specifies the name of a cache ruleset for invaliadations. Its KeyTemplate is used to generate group keys for invalidations. Each message of an invalidation ruleset will be routed to its outlink directly. Once the response is successfully collected, CacheNode will invalidate the cache of the target ruleset based on the group keys. When you define an invalidation ruleset, make sure the ruleset referenced by the TargetRule has already been defined before the invalidation ruleset.

For static cache, CacheNode supports the update ruleset with TargetRule defined for a static cahce rule. When CacheNode invokes an update ruleset, The message payload will be saved into the cache with the given key. So the static cache will cache the data fed by the incoming messages.

If a ruleset has its preferred outlink to one of the collectibles but has no KeyTemplate defined, it is a simple rule to collect responses. In this rule, CacheNode just routs the requests to the outlink and collects the responses. There is no caching involved with this type of rules.

CacheNode maintains a dedicated cache for each of the cache rules. But it is assumed that the caching keys are unique across all caches. If you run into key conflict with CacheNode, please use a different instance of CacheNode.

CacheNode has two properties to control timing. They are Heartbeat in sec and SessionTimeout in sec. Heartbeat is the frequncy to run the sanity check on pending requests. By default, it is 120 sec. SessionTimeout controls the caching time for the templates of JDBC queries. By default, it is 3600 sec.

You are free to choose any names for the three fixed outlinks. But CacheNode always assumes the first outlink for done, the second for failure and the third for nohit. The rest of the outlinks are for workers. It is OK for those three fixed outlinks to share the same name. Please make sure the first fixed outlink has the actual capacity no less than that of the uplink.

Author:

yannanlu@yahoo.com

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`OPTION_FILE`
`static int`	`OPTION_FTP`
`static int`	`OPTION_HTTP`
`static int`	`OPTION_JDBC`
`static int`	`OPTION_JMS`
`static int`	`OPTION_JMX`
`static int`	`OPTION_MONGO`
`static int`	`OPTION_NONE`
`static int`	`OPTION_REDIS`
`static int`	`OPTION_RIAK`
`static int`	`OPTION_STATIC`
`static int`	`OPTION_TCP`
`static int`	`OPTION_UDP`

Fields inherited from class org.qbroker.node.Node
assetList, bufferSize, callbackMethod, capacity, cbw, cells, cfgList, chkptExpiration, debug, DEBUG_COLL, DEBUG_DIFF, DEBUG_FBAK, DEBUG_INIT, DEBUG_PASS, DEBUG_PROP, DEBUG_REPT, DEBUG_UPDT, displayMask, displayPropertyName, linkName, LOAD_HIGH, LOAD_LOW, LOAD_MEDIUM, msgList, name, operation, RESET_ALL, RESET_MAP, RESET_NONE, RESET_SOME, ruleList, status, TYPE_ACTION, TYPE_AGGREGATE, TYPE_BYPASS, TYPE_CACHE, TYPE_COLLECT, TYPE_DELIVER, TYPE_FORMAT, TYPE_JSONPATH, TYPE_JSONT, TYPE_MAPREDUCE, TYPE_NONE, TYPE_PARSER, TYPE_PICKUP, TYPE_PIPE, TYPE_PUBLISH, TYPE_ROUNDROBIN, TYPE_SCREEN, TYPE_SCRIPT, TYPE_SERVICE, TYPE_SORT, TYPE_SPLIT, TYPE_SPREAD, TYPE_WEIGHTED, TYPE_XPATH, TYPE_XSLT, waitTime, xaMode

Fields inherited from interface org.qbroker.node.MessageNode
ASSET_THR, ASSET_URI, ASSET_XQ, META_MAP, META_MSG, META_OUT, META_RULE, META_XQ, MSG_BID, MSG_CID, MSG_OID, MSG_RID, MSG_TID, MSG_TIME, NODE_CLOSED, NODE_DISABLED, NODE_PAUSE, NODE_READY, NODE_RETRYING, NODE_RUNNING, NODE_STANDBY, NODE_STOPPED, OUT_CAPACITY, OUT_COUNT, OUT_DEQ, OUT_EXTRA, OUT_LENGTH, OUT_MODE, OUT_NRULE, OUT_OFFSET, OUT_ORULE, OUT_QDEPTH, OUT_QIPPS, OUT_QSTATUS, OUT_QTIME, OUT_SIZE, OUT_STATUS, OUT_TIME, RULE_COUNT, RULE_DMASK, RULE_EXTRA, RULE_GID, RULE_MODE, RULE_OID, RULE_OPTION, RULE_PEND, RULE_PID, RULE_SIZE, RULE_STATUS, RULE_TIME, RULE_TTL

Constructor Summary

Constructors
Constructor and Description

CacheNode(java.util.Map props)

Constructors
Constructor and Description
`CacheNode(java.util.Map props)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` It closes all resources and cleans up all list, cache, metadata, etc.
`protected int`	`feedback(XQueue in, long milliSec)` It returns the number of done messages removed from the input XQueue.
`protected void`	`finalize()`
`int`	`getOutLinkBoundary()` returns the BOUNDARY which is the lowest id of outlinks for collectibles so that any outlink with either the same id or a higher id is for collectibles.
`protected static int`	`getRequestType(java.lang.String type)` returns the id for the request or 0 if the type is not supported
`protected java.util.Map<java.lang.String,java.lang.Object>`	`initRuleset(long tm, java.util.Map ph, long[] ruleInfo)` It initializes a new ruleset with the ruleInfo and returns the rule upon success.
`protected int`	`passthru(long currentTime, javax.jms.Message msg, XQueue in, int rid, int oid, int cid, int tid)` It passes the message from the input XQueue over to an output XQueue and returns 1 upon success or 0 otherwise.
`void`	`propagate(XQueue in, XQueue[] out)` picks up a message from input queue and evaluates its content to decide which output queue to propagate
`int`	`removeRule(java.lang.String key, XQueue in)` It removes the rule from the ruleList and returns the rule id upon success.
`int`	`replaceRule(java.lang.String key, java.util.Map ph, XQueue in)` It replaces the existing rule of the key and returns its id upon success.
`void`	`resetMetaData(XQueue in, XQueue[] out)` cleans up MetaData for all XQs and messages
`int`	`updateParameters(java.util.Map props)` It updates the parameters of the node with the given property map.

Methods inherited from class org.qbroker.node.Node
addRule, callback, checkpoint, collectAll, containsRule, containsXQ, forcethru, getCapacity, getCapacity, getDebugMode, getDisplayMask, getDisplayProperties, getLinkName, getLinkName, getMetaData, getName, getNumberOfOutLinks, getNumberOfRules, getOperation, getRuleName, getStatus, getXAMode, getXAMode, internalXQSupported, list, listPendings, refreshRule, renameRule, restore, rotateRule, setDebugMode, setDisplayMask, setDisplayProperties, setStatus, show, takeback, takebackEnabled

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - OPTION_NONE
```
public static final int OPTION_NONE
```
    See Also:
    
    Constant Field Values
  - OPTION_JDBC
```
public static final int OPTION_JDBC
```
    See Also:
    
    Constant Field Values
  - OPTION_HTTP
```
public static final int OPTION_HTTP
```
    See Also:
    
    Constant Field Values
  - OPTION_FILE
```
public static final int OPTION_FILE
```
    See Also:
    
    Constant Field Values
  - OPTION_FTP
```
public static final int OPTION_FTP
```
    See Also:
    
    Constant Field Values
  - OPTION_TCP
```
public static final int OPTION_TCP
```
    See Also:
    
    Constant Field Values
  - OPTION_UDP
```
public static final int OPTION_UDP
```
    See Also:
    
    Constant Field Values
  - OPTION_JMS
```
public static final int OPTION_JMS
```
    See Also:
    
    Constant Field Values
  - OPTION_JMX
```
public static final int OPTION_JMX
```
    See Also:
    
    Constant Field Values
  - OPTION_RIAK
```
public static final int OPTION_RIAK
```
    See Also:
    
    Constant Field Values
  - OPTION_MONGO
```
public static final int OPTION_MONGO
```
    See Also:
    
    Constant Field Values
  - OPTION_REDIS
```
public static final int OPTION_REDIS
```
    See Also:
    
    Constant Field Values
  - OPTION_STATIC
```
public static final int OPTION_STATIC
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - CacheNode
```
public CacheNode(java.util.Map props)
```
- Method Detail
  - updateParameters
```
public int updateParameters(java.util.Map props)
```
    Description copied from class: Node
    
    It updates the parameters of the node with the given property map. Upon success, it returns the number of parameters modified. It is not MT-Safe.
    
    Specified by:
    
    updateParameters in interface MessageNode
    
    Overrides:
    
    updateParameters in class Node
  - initRuleset
```
protected java.util.Map<java.lang.String,java.lang.Object> initRuleset(long tm,
                                                                       java.util.Map ph,
                                                                       long[] ruleInfo)
```
    It initializes a new ruleset with the ruleInfo and returns the rule upon success. Otherwise, it throws an exception or returns null.
    
    Specified by:
    
    initRuleset in class Node
  - removeRule
```
public int removeRule(java.lang.String key,
                      XQueue in)
```
    It removes the rule from the ruleList and returns the rule id upon success. It is not MT-Safe.
    
    Specified by:
    
    removeRule in interface MessageNode
    
    Overrides:
    
    removeRule in class Node
  - replaceRule
```
public int replaceRule(java.lang.String key,
                       java.util.Map ph,
                       XQueue in)
```
    It replaces the existing rule of the key and returns its id upon success. It is not MT-Safe.
    
    Specified by:
    
    replaceRule in interface MessageNode
    
    Overrides:
    
    replaceRule in class Node
  - propagate
```
public void propagate(XQueue in,
                      XQueue[] out)
               throws javax.jms.JMSException
```
    picks up a message from input queue and evaluates its content to decide which output queue to propagate
    
    Specified by:
    
    propagate in interface MessageNode
    
    Specified by:
    
    propagate in class Node
    
    Throws:
    
    javax.jms.JMSException
  - passthru
```
protected int passthru(long currentTime,
                       javax.jms.Message msg,
                       XQueue in,
                       int rid,
                       int oid,
                       int cid,
                       int tid)
```
    It passes the message from the input XQueue over to an output XQueue and returns 1 upon success or 0 otherwise. If tid is less than 0, msg will not be put back to uplink in case of failure.
    
    Overrides:
    
    passthru in class Node
  - feedback
```
protected int feedback(XQueue in,
                       long milliSec)
```
    It returns the number of done messages removed from the input XQueue. If milliSec is less than 0, there is no wait and it tries to collect all cells. Otherwise, it just tries to collect the first collectible cell.
    
    Overrides:
    
    feedback in class Node
  - resetMetaData
```
public void resetMetaData(XQueue in,
                          XQueue[] out)
```
    cleans up MetaData for all XQs and messages
    
    Specified by:
    
    resetMetaData in interface MessageNode
    
    Overrides:
    
    resetMetaData in class Node
  - getOutLinkBoundary
```
public int getOutLinkBoundary()
```
    returns the BOUNDARY which is the lowest id of outlinks for collectibles so that any outlink with either the same id or a higher id is for collectibles. The EXTERNAL_XA bit of all outlinks for collectibles has to be disabled by the container to stop ack propagations downsstream.
    
    Specified by:
    
    getOutLinkBoundary in interface MessageNode
    
    Overrides:
    
    getOutLinkBoundary in class Node
  - close
```
public void close()
```
    Description copied from class: Node
    
    It closes all resources and cleans up all list, cache, metadata, etc. Once it is closed, it can not be used any more.
    
    Specified by:
    
    close in interface MessageNode
    
    Overrides:
    
    close in class Node
  - finalize
```
protected void finalize()
```
    Overrides:
    
    finalize in class Node
  - getRequestType
```
protected static final int getRequestType(java.lang.String type)
```
    returns the id for the request or 0 if the type is not supported

Class CacheNode

Field Summary

Fields inherited from class org.qbroker.node.Node

Fields inherited from interface org.qbroker.node.MessageNode

Constructor Summary

Method Summary

Methods inherited from class org.qbroker.node.Node

Methods inherited from class java.lang.Object

Field Detail

OPTION_NONE

OPTION_JDBC

OPTION_HTTP

OPTION_FILE

OPTION_FTP

OPTION_TCP

OPTION_UDP

OPTION_JMS

OPTION_JMX

OPTION_RIAK

OPTION_MONGO

OPTION_REDIS

OPTION_STATIC

Constructor Detail

CacheNode

Method Detail

updateParameters

initRuleset

removeRule

replaceRule

propagate

passthru

feedback

resetMetaData

getOutLinkBoundary

close

finalize

getRequestType