org.trimou.handlebars

Class NumericExpressionHelper

java.lang.Object

org.trimou.engine.config.AbstractConfigurationAware

org.trimou.handlebars.AbstractHelper

org.trimou.handlebars.BasicHelper

org.trimou.handlebars.NumericExpressionHelper

All Implemented Interfaces:

ConfigurationAware, Helper

public class NumericExpressionHelper
extends BasicHelper

A simple numeric expression helper. During evaluation all the params are converted to BigDecimals. For the list of supported operators see the NumericExpressionHelper.Operator enum values, e.g.:

 {{numExpr val op="neg" out='It is a negative number!'}}
 {{#numExpr val "90" op="gt"}}
  val > 90
 {{/numExpr}}
 {{#numExpr val 10 op="eq"}}
  val == 10
 {{/numExpr}}
 {{#numExpr val1 val2 op="le"}}
  val1 <= val2
 {{/numExpr}}
 {{#numExpr val "1" 2 '3' op="in"}}
  val = 1 or val = 2 or val = 3
 {{/numExpr}}
 

It's also possible to specify the default operator (NumericExpressionHelper.Operator.EQ by default) so that the op param may be ommitted:

 {{#gt val1 10}} val1 > 10 {{/gt}}
 

Sometimes it also makes sense to register the helper with a name derived from the default operator or even register a helper instance for each operator - see forEachOperator().

Author:

Martin Kouba

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NumericExpressionHelper.Operator

Field Summary

Fields inherited from class org.trimou.handlebars.BasicHelper

HELPER_TAG_TYPES

Fields inherited from class org.trimou.engine.config.AbstractConfigurationAware

configuration

Constructor Summary

Constructors

Constructor and Description
NumericExpressionHelper()
NumericExpressionHelper(NumericExpressionHelper.Operator defaultOperator)

Method Summary

Modifier and Type	Method and Description
void	execute(Options options) Execute the helper.
static HelpersBuilder	forEachOperator() Enum.toString() is used as the helper name.
static void	forEachOperator(BiConsumer<String,Helper> consumer) Invokes the specified consumer for all operators.
static HelpersBuilder	forEachOperator(HelpersBuilder builder)
void	validate(HelperDefinition definition) Helper should validate the tag definition (e.g. number of parameters) during compilation and fail fast if necessary.

Methods inherited from class org.trimou.handlebars.BasicHelper

allowedTagTypes, getRequiredHashKeys, getSupportedHashKeys, numberOfRequiredHashEntries, numberOfRequiredParameters

Methods inherited from class org.trimou.handlebars.AbstractHelper

append, convertAndAppend, convertValue, init, isSection, isUnescapeVariable, isVariable

Methods inherited from class org.trimou.engine.config.AbstractConfigurationAware

checkNotInitialized, init

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.trimou.engine.config.ConfigurationAware

getConfigurationKeys, init

Constructor Detail

NumericExpressionHelper

public NumericExpressionHelper()

NumericExpressionHelper

public NumericExpressionHelper(NumericExpressionHelper.Operator defaultOperator)

Parameters:

defaultOperator -

Method Detail

forEachOperator

public static HelpersBuilder forEachOperator()

Enum.toString() is used as the helper name.

Returns:

a new builder instance with NumericExpressionHelper instance registered for each NumericExpressionHelper.Operator

forEachOperator

public static HelpersBuilder forEachOperator(HelpersBuilder builder)

Parameters:

builder -

Returns:

an enriched builder instance with NumericExpressionHelper instance registered for each NumericExpressionHelper.Operator

forEachOperator

public static void forEachOperator(BiConsumer<String,Helper> consumer)

Invokes the specified consumer for all operators. Enum.toString() is used as the first argument and the corresponding NumericExpressionHelper instance as the second argument.

Parameters:

consumer -

execute

public void execute(Options options)

Description copied from interface: Helper

Execute the helper.

validate

public void validate(HelperDefinition definition)

Description copied from interface: Helper

Helper should validate the tag definition (e.g. number of parameters) during compilation and fail fast if necessary. A MustacheException with code MustacheProblem.COMPILE_HELPER_VALIDATION_FAILURE should be thrown in case of validation failure occurs.

Specified by:

validate in interface Helper

Overrides:

validate in class BasicHelper