org.imixs.workflow.engine.plugins

Class RulePlugin

java.lang.Object

org.imixs.workflow.engine.plugins.AbstractPlugin

org.imixs.workflow.engine.plugins.RulePlugin

All Implemented Interfaces:

Plugin

public class RulePlugin
extends AbstractPlugin

The Imixs Rule Plugin evaluates a business rule provided by the current ActiviyEntity. A business rule can be written in any script language supported by the JVM. The Script Language is defined by the property 'txtBusinessRuleEngine' from the current Event element. The script is defined by the property 'txtBusinessRule'. The Script can access all basic item values from the current workItem and also the event by the provided JSON objects 'workitem' and 'event'. // test first value of the workitem attribute 'txtname' var isValid = ('Anna'==workitem.txtname[0]); A script can add new values for the current workitem by providing the JSON object 'result'. var result={ someitem:'Hello World', somenumber:1}; Also change values of the event object can be made by the script. These changes will be reflected back for further processing. // disable mail event.keymailenabled='0'; A script can set the variables 'isValid' and 'followUp' to validate a workItem or set a new followUp activity. result={ isValid:false }; If the script set the variable 'isValid' to false then the plugin throws a PluginExcpetion. The Plugin evaluates the variables 'errorCode' and errorMessage. If these variables are set by the Script then the PluginException will be updates with the corresponding errorCode and the 'errorMessage' as params[]. If no errorCode is set then the errorCode of the PluginException will default to 'VALIDATION_ERROR'. If the script set the variable 'followUp' the follow-up behavior of the current ActivityEntity will be updated. If a script can not be evaluated by the scriptEngin a PluginExcpetion with the errorCode 'INVALID_SCRIPT' will be thrown. NOTE: all variable names are case sensitive! All JSON object elements are lower case!

Version:

3.0

Author:

Ralph Soika

Field Summary

Fields

Modifier and Type	Field and Description
static String	INVALID_SCRIPT
static String	VALIDATION_ERROR

Fields inherited from class org.imixs.workflow.engine.plugins.AbstractPlugin

INVALID_ITEMVALUE_FORMAT, INVALID_PROPERTYVALUE_FORMAT

Constructor Summary

Constructors

Constructor and Description
RulePlugin()

Method Summary

Modifier and Type	Method and Description
ScriptEngine	evaluateBusinessRule(ItemCollection documentContext, ItemCollection activity) This method evaluates the business rule defined by the provided activity.
Object[]	evaluateNativeScriptArray(ScriptEngine engine, String expression) This method evaluates a script variable as an native Script array from the script engine.
ItemCollection	run(ItemCollection adocumentContext, ItemCollection adocumentActivity) The run method evaluates a script provided by an activityEntity with the specified scriptEngine.

Methods inherited from class org.imixs.workflow.engine.plugins.AbstractPlugin

close, formatItemValues, formatItemValues, getCtx, getWorkflowService, init, mergeFieldList, mergeValueList, replaceDynamicValues, uniqueList

Methods inherited from class java.lang.Object

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

Field Detail

INVALID_SCRIPT

public static final String INVALID_SCRIPT

See Also:

Constant Field Values

VALIDATION_ERROR

public static final String VALIDATION_ERROR

See Also:

Constant Field Values

Constructor Detail

RulePlugin

public RulePlugin()

Method Detail

run

public ItemCollection run(ItemCollection adocumentContext,
                          ItemCollection adocumentActivity)
                   throws PluginException

The run method evaluates a script provided by an activityEntity with the specified scriptEngine. After successful evaluation the method verifies the object value 'isValid'. If isValid is false then the method throws a PluginException. In addition the method evaluates the object values 'errorCode' and 'errorMessage' which will be part of the PluginException. If 'isValid' is true or undefined the method evaluates the object value 'followUp'. If a followUp value is defined by the script the method update the model follow up definition. If a script changes properties of the activity entity the method will evaluate these changes and update the ItemCollection for further processing.

Throws:

PluginException

evaluateBusinessRule

public ScriptEngine evaluateBusinessRule(ItemCollection documentContext,
                                         ItemCollection activity)
                                  throws PluginException

This method evaluates the business rule defined by the provided activity. The method returns the instance of the script engine which can be used to continue evaluation. If a rule evaluation was not successful, the method returns null.

Parameters:

adocumentContext -

adocumentActivity -

Returns:

ScriptEngine instance

Throws:

PluginException

evaluateNativeScriptArray

public Object[] evaluateNativeScriptArray(ScriptEngine engine,
                                          String expression)

This method evaluates a script variable as an native Script array from the script engine. The method returns a Object array with the variable values. If the javaScript var is a String a new Array will be created. If the javaScript var is a NativeArray the method tries to create a java List object. See the following examples used by the Rhino JavaScript engine bundled with Java 6. http://www.rgagnon.com/javadetails/java-0640.html

Returns: