org.qbroker.node

Class FormatNode

java.lang.Object

org.qbroker.node.Node

org.qbroker.node.FormatNode

All Implemented Interfaces:

MessageNode

public class FormatNode
extends Node

FormatNode formats JMS Message body and header fields according to rulesets. Based on the rulesets, it filters messages into three outlinks: done for all the formatted messages, nohit for those messages do not belong to any rulesets, failure for the messages failed in the formatting process.

FormatNode contains a number of predefined rulesets. These rulesets categorize messages into non-overlapping groups. Therefore, each rule defines a unique message group. The ruleset also defines the formatter and its formatting rules for the group. Different groups may have different formatter or different format parameters. Due to JMS specifications, you have to clear user properties before setting user properties on a readonly message. You can specify ResetOption in a ruleset so that the message header will be reset for modifications. Its value is 0 for no reset, 1 for optional reset and 2 for guaranteed reset.

Each ruleset has an array of FormatterArgument. A FormatterArgument contains a name specifying what to be formatted and two sets of format operations. The first operation set lists format templates in the name of Template. The other is the array of substitutions with the name of Substitution. Each Template appends the previous non-empty text to the variable and sets the next initial text for its corresponding Substitutions. If the first template is null, the initial text will be the variable itself. Each Substitution modifies the text before it is appended to the variable. The associations between the Templates and Substitutions are based on their positions. Either Template or Substitution can be null for no action and a place holder. Therefore, you can insert multiple null Templates so that the associated Substitutions will be able to modify the same text in turns. FormatNode will apply all the operations of FormatterArguments on the incoming message in the order of the list. If any of the operations fails, the message will be routed to failure outlink.

If ClassName is not defined in the rule, the rule is for the default formatter. In this case, it accepts a template via URITemplate for the path to a template file which will be used to format the message body. If URITemplate is defined, the rule will load the template from the file and cache it at the first application to the message. The format result will be set back to the message body. The cache count of templates for the rule will be stored to RULE_PEND. The cache count will be updated when the session times out which is determined by SessionTimeout. A static template file can also be specified via TemplateFile.

FormatNode allows developers to plugin their own formatters by specifying the ClassName for the plugin. The requirement is minimum. The class should have a public method of format() that takes a JMS Message to be formatted as the only argument. The return object must be a String of null meaning OK, or an error message otherwise. It must have a constructor taking a Map as the only argument for configurations. Based on the map properties for the constructor, developers should define configuration parameters in the base of FormatterArgument. FormatNode will pass the data to the plugin's constructor as an opaque object during the instantiation of the plugin. In the normal operation, FormatNode will invoke the method to format the incoming messages. The method should never acknowledge any message in any case.

In case a plugin needs to connect to external resources for the dynamic format process, it should define an extra method of close() to close all the external resources gracefully. Its format method should also be able to detect the disconnections and cleanly reconnect to the resources automatically. If the container wants to stop the node, it will call the resetMetaData() in which the methods of close() of all formatters will be called in order to release all external resources.

You are free to choose any names for the three fixed outlinks. But FormatNode always assumes the first outlink for done, the second for failure and the last for nohit.

Author:

yannanlu@yahoo.com

Field Summary

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
FormatNode(java.util.Map props)

Method Summary

Modifier and Type	Method and Description
void	close() It closes all resources and cleans up all list, cache, metadata, etc.
protected void	finalize()
int	getMetaData(int type, int id, long[] data) overwrites the implementation for storing total cache in NOHIT
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.
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.
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, feedback, forcethru, getCapacity, getCapacity, getDebugMode, getDisplayMask, getDisplayProperties, getLinkName, getLinkName, getName, getNumberOfOutLinks, getNumberOfRules, getOperation, getOutLinkBoundary, getRuleName, getStatus, getXAMode, getXAMode, internalXQSupported, list, listPendings, passthru, refreshRule, renameRule, resetMetaData, 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

Constructor Detail

FormatNode

public FormatNode(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

getMetaData

public int getMetaData(int type,
                       int id,
                       long[] data)

overwrites the implementation for storing total cache in NOHIT

Specified by:

getMetaData in interface MessageNode

Overrides:

getMetaData 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