Package org.broadleafcommerce.common.rule

Class MvelHelper

java.lang.Object

org.broadleafcommerce.common.rule.MvelHelper

public class MvelHelper
extends Object

Helper class for some common rule functions that can be called from mvel as well as utility functions to make calling MVEL rules within Broadleaf easier.

An instance of this class is available to the mvel runtime under the variable name MvelHelper with the following functions:

convertField(type, fieldValue) toUpperCase(value)

Author:

Jeff Fischer

Field Summary

Fields

Modifier and Type	Field	Description
static final String	BLC_RULE_MAP_PARAM
static final String	REQUEST_DTO

Constructor Summary

Constructors

Constructor	Description
MvelHelper()

Method Summary

Modifier and Type	Method	Description
static Map<String,Object>	buildMvelParameters()	Builds parameters using time, request, customer, and cart.
static Object	convertField(String type, String fieldValue)	Converts a field to the specified type.
static String	currentTime()
static boolean	evaluateRule(String rule, Map<String,Object> ruleParameters)	Returns true if the passed in rule passes based on the passed in ruleParameters.
static boolean	evaluateRule(String rule, Map<String,Object> ruleParameters, Map<String,Serializable> expressionCache)	Evaluates the passed in rule given the passed in parameters.
static boolean	evaluateRule(String rule, Map<String,Object> ruleParameters, Map<String,Serializable> expressionCache, Map<String,Class<?>> additionalContextImports)
protected static String[]	getRuleAttributeMaps()	Returns an array of attribute map field names that we need to do replacements for in modifyExpression(String, Map, ParserContext)
protected static String	modifyExpression(String rule, Map<String,Object> ruleParameters, org.mvel2.ParserContext context)	Provides a hook point to modify the final expression before it's built.
protected static void	populateParamsFromMap(Map<String,Object> blcRuleMap, Map<String,Object> mvelParameters)
static void	setTestMode(boolean testMode)	When true, LOG.info statement will be suppressed.
static String	subtractFromCurrentTime(int days)
static Object	toUpperCase(String value)
protected static String	unescapeUnicode(String input)	Decodes unicode escapes like " into actual characters.

Methods inherited from class java.lang.Object

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

Field Details

BLC_RULE_MAP_PARAM

public static final String BLC_RULE_MAP_PARAM

See Also:

• Constant Field Values

REQUEST_DTO

public static final String REQUEST_DTO

See Also:

• Constant Field Values

Constructor Details

MvelHelper

public MvelHelper()

Method Details

convertField

public static Object convertField(String type,
 String fieldValue)

Converts a field to the specified type. Useful when

Parameters:

type -

fieldValue -

Returns:

toUpperCase

public static Object toUpperCase(String value)

currentTime

public static String currentTime()

subtractFromCurrentTime

public static String subtractFromCurrentTime(int days)

evaluateRule

public static boolean evaluateRule(String rule,
 Map<String,Object> ruleParameters)

Returns true if the passed in rule passes based on the passed in ruleParameters.

Also returns true if the rule is blank or null.

Calls the evaluateRule(String, Map, Map) method passing in the DEFAULT_EXPRESSION_CACHE. For systems that need to cache a large number of rule expressions, an alternate cache can be passed in. The default cache is able to cache up to 1,000 rule expressions which should suffice for most systems.

Parameters:

rule -

ruleParameters -

Returns:

evaluateRule

public static boolean evaluateRule(String rule,
 Map<String,Object> ruleParameters,
 Map<String,Serializable> expressionCache)

Evaluates the passed in rule given the passed in parameters.

Parameters:

rule -

ruleParameters -

Returns:

evaluateRule

public static boolean evaluateRule(String rule,
 Map<String,Object> ruleParameters,
 Map<String,Serializable> expressionCache,
 Map<String,Class<?>> additionalContextImports)

Parameters:

rule -

ruleParameters -

expressionCache -

additionalContextImports - additional imports to give to the ParserContext besides "MVEL" (MVEL and "MvelHelper" (MvelHelper) since they are automatically added

Returns:

modifyExpression

protected static String modifyExpression(String rule,
 Map<String,Object> ruleParameters,
 org.mvel2.ParserContext context)

Provides a hook point to modify the final expression before it's built. By default, this looks for attribute maps and replaces them such that it does string comparison.

For example, given an expression like getProductAttributes()['somekey'] == 'someval', getProductAttributes()['somekey'] actually returns a ProductAttribute object, not a String, so the comparison is wrong. Instead, we actually want to do this: getProductAttributes().?get('somekey').?value == 'someval'. This function performs that replacement

The modification regex will support both simple and complex expressions like: "(MvelHelper.convertField("INTEGER",orderItem.?product.?getProductAttributes()["myinteger"])>0&&MvelHelper.convertField("INTEGER",orderItem.?product.?getProductAttributes()["myinteger"])<10)"

Parameters:

rule - the rule to replace

Returns:

a modified version of rule

unescapeUnicode

protected static String unescapeUnicode(String input)

Decodes unicode escapes like " into actual characters.

getRuleAttributeMaps

protected static String[] getRuleAttributeMaps()

Returns an array of attribute map field names that we need to do replacements for in modifyExpression(String, Map, ParserContext)

setTestMode

public static void setTestMode(boolean testMode)

When true, LOG.info statement will be suppressed. Should only be set from within MvelHelperTest. Prevents an error from displaying during unit test runs.

Parameters:

testMode -

buildMvelParameters

public static Map<String,Object> buildMvelParameters()

Builds parameters using time, request, customer, and cart.

Should be called from within a valid web request.

Returns:

populateParamsFromMap

protected static void populateParamsFromMap(Map<String,Object> blcRuleMap,
 Map<String,Object> mvelParameters)